[volt-nuts]
Hi, Be sure to have "END" set to "ALWAYS" before using GPIB. It needs to be reset after a 3458A reset. Charlie ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Banana jack shorting straps
Hi Mark, On my 3458a calibration short I use a short piece of #12 copper house wire bent into a "C" shape that just drops into the banana jack holes. It has the advantage low resistance with low thermal mass and the oxide layer is broken when you tighten the nuts. HP recommended this in their calibration manual. Charlie ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 3458A question
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Re: [volt-nuts] Oldaker is no more...
You might give the Fluke extendable sharp point leads a try. They are hardened enough to not bend with use like the knock offs. They are dear at about $44 US so I am still regretting the untimely loss of the last ones. Charlie On 2/2/2016 8:10 PM, Mark Sims wrote: I stopped by my favorite electronics store to buy some more Oldaker meter probes. Alas, I was told that Oldaker had a fire and is no longer in business. They were a small (7 person), family owned business that made really nice and affordable test leads. Apparently they don't plan on restarting the business. I've used their leads/probes for years and have never had one fail. And the tips are damn sharp... ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Fluke 720a self calibration repair
Hi David, My 720A's trimpots were original. I have them somewhere but they are a bit scarce right now. Anyway they were 20 turn wire wound trimpots. I suggest that you use wire wound ones and if 20 turn pots are not within your budget then 10 turn will not be too much of an issue. On one or two of my trimpots were very sensitive to adjustment so 20 turn is best. Wire wound trimpots are far more reliable than the others. If they do have a problem with the contact resistance going up it is usually fixed by just giving the adjustment screw a little turn. Properly fixed my 720A tracks my 3458A very closely. The circuit board was cleaned and clear coated after manufacture. Be careful about creating leakage paths. Never spray anything on the circuitry. I used to use Krylon to paint repaired circuit boards but decided to just clean each connection with alcohol swab and call it a day. I forgot to mention that all the decades need many revolutions to condition the contacts before calibration and before each important use. Charlie On 9/29/2015 12:08 AM, Bill Gold wrote: David: I just looked inside my 720A at the 20 turn 5K trimpots. They are Bourns 3005P-502 printed on them, cermets, standard 3/4", tempco 50 ppm. So the replacement is available directly from stock and nothing fancy. Mine are date code 8412 so my unit was built somewhere in the mid '80s. Not too sure where the idea of a wirewound pot came from here. They are more than a little pricey at $13.98 ea from Allied. Looks like you need 24 to replace them all in the "A" and "B" decades. So that would be $335.52 unless you buy 25 or more at which time the price drops to $12.51 which totals $312.75. They come in tubes of 25 each which accounts for the price drop. Digikey is $14.35 and Mouser is $14.35. Wow! Expensive little devils. On the other hand (left) Digikey shows a unit from "TT Electronics/BI Technologies" for $1.40 ea. Interesting. Why such a massive difference in price? These are 100 ppm but as I have noted in another posting the tempco isn't very important. It's the resistors in the oil filled can that set the overall stability. Bill - Original Message - From: "David Garrido" To: Sent: Saturday, September 26, 2015 5:05 AM Subject: Re: [volt-nuts] Fluke 720a self calibration repair Thank you for all of the input on this folks. Does anyone have a copy of the datasheet for the original Ramo-Eltra P/N 3800P-502? The reason I ask is that the price of these parts is driven in part by the tempco and I found info that indicated 20ppm/C on one website, but that was not a DS, just a listing of the info. If they can be 50ppm/C or even 100ppm/C, then the price drops exponentially. I will do whatever is necessary to maintain or (LOL) improve the 720’s legendary performance. Cheers, David ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Fluke 720a self calibration repair
Hi David, I had to look it up. The company was Arrow (800 833 3557). The pots were manufactured by Bournes with a manufacturer part number of 300SP-1-502. Unit cost $7.73 in 2011. I bought 26 so my cost was about $200. I wanted a "Manufactured in America" part but can't remember if that was too pricey or not. Charlie On 9/25/2015 9:45 AM, David Garrido wrote: I like that Idea. Do you recall the part number of the resistors you found? Cheers, David ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Fluke 720a self calibration repair
Hi David, I had the same problem with my Fluke 720A, among other problems. The problem was the plastic for the adjustment pots had disintegrated with age and a couple of them had quit working. I ended up fixing the unit but removal of the bad pots made it obvious that the other "working" pots were just hanging on. As I removed the bad pots they kind of fell apart. I have been there before so I found a good price on 30 new pots and replaced them all at once. It really made a new instrument out of my 720A. I was amazed how well it agreed with my Agilent 3458A, to better than the spec! It was nice to have confirmation of the linearity my 3458A since it has not been out for calibration since it was almost new. Charlie On 9/24/2015 9:38 AM, David Garrido wrote: Hello All, I am trying to track down what I think is a small issue in the calibration of my new to me 720a. I am dreadfully paranoid of jacking something up in the process and need a little hand holding. I was going through the Self Calibration steps and every thing was going well up to the adjustment of the "A 1.0" decade switch position. All of the variable resistors up to that point needed to be turned CW in order to null the appropriate switch position. The “A 1.0” adjustment pot does not null the switch position and is not getting any closer than about 2.5uV. I verified the meter balance between every other step. I have checked, in circuit, R302 and R303 and I am getting a VERY SOLID reading of 9.896 on all of those. Of course, checking R1006 and R1010 give me significantly different readings than the stipulated 8.45k. I cannot seem to be able to find a CCW or CW limit to this resistor and I think I read somewhere that there are supposed to be run from end to end several times if an issue arises. Do these var resistors have limits? I need a little help moving forward. Cheers, David ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Wavetek 4912 For Sale
Hi Bob, I would like to buy your 4812 DC Standard if it is not too expensive to ship. I live in the US at zip 98261 (far N.W. in U.S.). Where is the Standard located? Charlie On 8/21/2015 12:44 PM, Four Designs Company wrote: I have an inoperative 4912 DC Standard for sale. The batteries are completely dead, and will need to be replaced. I have powered it up with the battery pack disconnected, but cannot get an output from the front panel jacks. I am not sure if it would normally output without good batteries. Decent condition, pictures on request. So, this is offered AS-IS. $300 plus shipping, CONUS only due to the size and weight. Thanks, Bob ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Precision resistor testing
I use a digital temperature controlled bath for my keeping my standard resistors at 25C. It's versatile since it can do precision temperature/time scans and can easily scan the range your interested in. Right now I have it set to 25.00C with one of my ancient 10K ohm standards. When I first bought my Leeds and Northrup resistors I wanted temperature info on all of them to see if there was an especially good one. I was scanning from 20C to 30C and writing down the resistance values at every 0.1C point. Like Frank mentioned, I went through the temperature range too fast and the data was useless do to hysteresis. Next time I went much slower and the data was OK. My bath has a change in temperature over time function so it will be much easier just to let the 3458A measure continuously and plot the output after the run. I can use Labview to plot the data in real time if I get the urge to "program". Use NPLC = 1000 and OHMSF for best results. Because of my old Leeds an Nothrup reistors I have to use a DELAY of 10S. Most standards don't need this but it's best to compare the resistors value at a Delay of 10S and the default Delay. They should be identical. I use the GPIB data port all the time and can't live without it. Charlie On 11/15/2014 1:48 PM, Richard Moore wrote: Thanks for the replies — I have all I need except an environmental test chamber to control temp. Of course, right now, I could stick the box outside and drop its temp by 20C — but I really only need a range of 20C +/- 5C. But as it turns out, I have a little portable insulated cooler/heater box for holding drinks and food in the car that has a big reversible Peltier block in it, so maybe I can finesse this temp testing… ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Solartron 7081 With Bad WR057 Diode
It's D110 on PCB6. After removing D110 the 7081 read about +2.5 microvolt with the input shorted with an external jumper. When I shorted the HI amp input with the MYTCHETT test point the 7081 read about -1.0 microvolt with low noise. I expect that the D101 (DPAD1) is the culprit. Presently: Compared to my ancient HP3458a (last calibrated in 1990 and still on CAL 1) the 7081 reads about 10 microvolts higher. The 7081 reads about 25 microvolts higher than my not quite as ancient Ag3458a. The Datron 4910 was calibrated by Fluke in March of 2012. I'm going to change out temperature sensitive parts and leaky parts and remeasure. Charlie At 10V input the 7081 reads about On 10/31/2014 12:30 PM, John May wrote: As a matter of interest which particular diode is causing these symptoms? On 31 October 2014 15:18, Todd Micallef wrote: Charlie, Calogic appears to sell directly, they may even send you a sample. I guess it wouldn't hurt to ask. Todd ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Solartron 7081 With Bad WR057 Diode
Littlediode is no more. The only other ebay seller has been caught re-branding and selling used as new. I have been looking at pico amp reverse cxurrent diodes that are still being sold and have not founds any that favorably compare with the DPAD1. The DPAD1 is only being sold by one source as far as my research has gone today. It is Linear Systems/micross. They are a bit dear at $4.35US each but could be used to upgrade the 7081's performance a small amount. I was ordering them last night and all was going well until they overcharged ($20US) for UPS ground. It's hard to trust a company that does that! David, I want to thank you for your 7081 information on your web site. I used the troubles you had with your 7081 repair as a starting point for my first repair and it saved me a lot of time. Nigel, thanks for letting me know aboutlittlediode and your experience with them. Charlie On 10/31/2014 4:30 AM, Nigel Clarke via volt-nuts wrote: I bought from Little Diode around 10 years ago, a variety of RF transistors similar to and including 2N3866 with the specific intention of comparing them for suitability in LF/HF active antennas. However all the devices they supplied looked to have been rebranded from the same generic stock, I'd had some experience of this in the past but it still took a LOT of effort before I finally got past the evasive responses and they admitted this was true, which of course made any comparison pretty pointless. They didn't refer to them as "generic", can't remember what expression they did use now in their initial responses but remember it wasn't something I'd come across before, but there were certainly no indications at the point of sale that these weren't original manufacturer's branded stock. Such rebranding and subterfuge was common amongst some at least of the aftermarket electronic valve suppliers in the late 1960s, a bog standard device going in one door could come out another as the ruggedised version, for example, and much more expensive, and it would seem similar practices lived on. I wouldn't touch them again with the proverbial barge pole, although I have to accept others may have had better experience. Regards Nigel GM8PZR In a message dated 31/10/2014 10:49:12 GMT Standard Time, david.partri...@perdrix.co.uk writes: I might be worth asking eBay vendor LittleDiode, they are the eBay shop for LittleDiode Components ... Regards, David Partridge -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Black Sent: 31 October 2014 00:09 To: volt-nuts@febo.com Subject: [volt-nuts] Solartron 7081 With Bad WR057 Diode My Solartron 7081 has a bad WR057 diode that needs to be replaced. It's a three terminal device that looks like two silicon diodes in parallel. It was making the meter read about 10.1V with a 10V input. Luckily it was temperature sensitive and was easy to find with freeze mist. Removal caused a shorted input to be about 2.5 microvolts high and a little noisy. I've not been able to find this device on the internet but thought that someone here might have seen this thing before. Charlie ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Solartron 7081 With Bad WR057 Diode
My Solartron 7081 has a bad WR057 diode that needs to be replaced. It's a three terminal device that looks like two silicon diodes in parallel. It was making the meter read about 10.1V with a 10V input. Luckily it was temperature sensitive and was easy to find with freeze mist. Removal caused a shorted input to be about 2.5 microvolts high and a little noisy. I've not been able to find this device on the internet but thought that someone here might have seen this thing before. Charlie ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
Hi Adrian, I had some trouble testing my EL 1400's with my precsion attenuator (1.2Ghz B/W) not having a small enough minimum step for easy setting. It was fairly stable though. I checked everything with my scope and it was fairly flat to 20mhz with a gentle falloff to 30mhz if I remember correctly. The EL 1400's are "useable" to 300mhz with corrections that I don't have. I will keep an eye out for a low priced 4920. It will have to be broken bad enough to be low priced though. Charlie On 9/1/2014 3:29 PM, acb...@gmx.de wrote: charlie, you can expand these tvcs by range resistors to work as higher voltage tvcs. if you do it right (rf-type setup) you can work up to a couple hundred khz with just minor additional error beyond its error in its orgininal voltage range. need to calibrate them however. using an attenuator is not a good idea, too unprecise. still tvcs are the most precise way to measure, if done right. pretty tme consuming though. but you need them e.g. to calibrate a 4920. adrian Gesendet: Sonntag, 31. August 2014 um 21:41 Uhr Von: "Charles Black" An: "Discussion of precise voltage measurement" Betreff: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Hi Stephen, Thanks for the info on the 4920M. It might be that I should pass on this but it is nice to know that it is probably working. If I don't have the necessary items needed for calibration it might still be a good source uncalibrated. I was hoping that the 4920 had better minimum voltage out steps than my present Rigol 4062 for 3458a AC calibration. I have two EL 1400 0.25V voltage thermal converters that I was trying to use in a test setup but they had such a low voltage range that I was forced to use my ATV-60 attenuator. It all kind of worked but a 0.1 db minimum step is a little course for easy use. The Rigol also suffers from this malady. Charlie On 8/31/2014 1:06 PM, Stephen Grady wrote: Charlie, The "Error Ur" is an under-range error; you have to apply an input above 10% of the range before it will display a reading. The 4920's are a very nice instrument. Their only problem is that they are all so old that they are reaching the stage where some components are drifting excessively or failing. I have come across 4920's that are drifting a little (more than there spec) between cals (and yes they need to be cal'd annually), another 4920 I came across had an intermittent failure in one of its power supplies. Kind Regards, Stephen Grady Sydney Australia -Original Message----- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Black Sent: Monday, 1 September 2014 3:19 AM To: b...@veritechmeasurements.com.au; Discussion of precise voltage measurement Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Hi Ben, I am going to check this out today to find if it might be helpfull around here for my AC calibration. It has an error message: "Error Ur" so some fixing is going to be needed. On the back it says it's got Option 80, whatever that is. Charlie On 8/31/2014 5:37 AM, ben wrote: Hello all, Just a heads up. I noted there is a lonely Datron / Wavetek 4920M AC voltmeter for sale on ebay, starting at US$650 (ending in 1 day !). I have little idea of its true working state or not (picture shows it powered on). If fully working it would be a good buy for an AC voltmeter that is, I reckon, better than an HP 3458A. Only drawback with these models is the voltage input shell is always earthed, not floating. I have two of these 4920M's already, not really tempted by a third. I have a paper copies of operator, calibration, and service manual if anyone interested. regards, ben. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
Hi, The auction winning bid was $1432. I was outbid by two people and never had an effect on the auction at all! Charlie On 9/1/2014 1:51 AM, ben wrote: Hello Stephen, I agree that the 4920's will often drift more than their spec after 1 year. I find it more convenient to derate them slightly - and use them wisely. Note the manual states their absolute specs are valid for 6 months, but I still maintain them on a 1 year cycle. Even when de-rated they still have very good short term stability over 10 minutes and for weeks after. On the discussion of inputs at low points in ranges, I find this is where the 4920M's will most often cause calibration failures against their specs. Perhaps optimistically, Datron has specified their absolute reading spec at, say, 3V range, to be +-30ppm of reading (40 to 20kHz) for any input from 30% to 100% of range. No floor or percentage of range limiting spec is stated. When the sad day finally arrives and I need to repair units I would resort to cannibilising parts from these 4920M's just to keep my more capable 4920 going. regards, ben. From: "Stephen Grady" Sent: Monday, September 01, 2014 5:37 AM To: "Discussion of precise voltage measurement" Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Charlie, The "Error Ur" is an under-range error; you have to apply an input above 10% of the range before it will display a reading. The 4920's are a very nice instrument. Their only problem is that they are all so old that they are reaching the stage where some components are drifting excessively or failing. I have come across 4920's that are drifting a little (more than there spec) between cals (and yes they need to be cal'd annually), another 4920 I came across had an intermittent failure in one of its power supplies. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Black Sent: Monday, 1 September 2014 3:19 AM To: b...@veritechmeasurements.com.au; Discussion of precise voltage measurement Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Hi Ben, I am going to check this out today to find if it might be helpfull around here for my AC calibration. It has an error message: "Error Ur" so some fixing is going to be needed. On the back it says it's got Option 80, whatever that is. Charlie On 8/31/2014 5:37 AM, ben wrote: Hello all, Just a heads up. I noted there is a lonely Datron / Wavetek 4920M AC voltmeter for sale on ebay, starting at US$650 (ending in 1 day !). I have little idea of its true working state or not (picture shows it powered on). If fully working it would be a good buy for an AC voltmeter that is, I reckon, better than an HP 3458A. Only drawback with these models is the voltage input shell is always earthed, not floating. I have two of these 4920M's already, not really tempted by a third. I have a paper copies of operator, calibration, and service manual if anyone interested. regards, ben. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
Hi Stephen, Thanks for the info on the 4920M. It might be that I should pass on this but it is nice to know that it is probably working. If I don't have the necessary items needed for calibration it might still be a good source uncalibrated. I was hoping that the 4920 had better minimum voltage out steps than my present Rigol 4062 for 3458a AC calibration. I have two EL 1400 0.25V voltage thermal converters that I was trying to use in a test setup but they had such a low voltage range that I was forced to use my ATV-60 attenuator. It all kind of worked but a 0.1 db minimum step is a little course for easy use. The Rigol also suffers from this malady. Charlie On 8/31/2014 1:06 PM, Stephen Grady wrote: Charlie, The "Error Ur" is an under-range error; you have to apply an input above 10% of the range before it will display a reading. The 4920's are a very nice instrument. Their only problem is that they are all so old that they are reaching the stage where some components are drifting excessively or failing. I have come across 4920's that are drifting a little (more than there spec) between cals (and yes they need to be cal'd annually), another 4920 I came across had an intermittent failure in one of its power supplies. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Black Sent: Monday, 1 September 2014 3:19 AM To: b...@veritechmeasurements.com.au; Discussion of precise voltage measurement Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Hi Ben, I am going to check this out today to find if it might be helpfull around here for my AC calibration. It has an error message: "Error Ur" so some fixing is going to be needed. On the back it says it's got Option 80, whatever that is. Charlie On 8/31/2014 5:37 AM, ben wrote: Hello all, Just a heads up. I noted there is a lonely Datron / Wavetek 4920M AC voltmeter for sale on ebay, starting at US$650 (ending in 1 day !). I have little idea of its true working state or not (picture shows it powered on). If fully working it would be a good buy for an AC voltmeter that is, I reckon, better than an HP 3458A. Only drawback with these models is the voltage input shell is always earthed, not floating. I have two of these 4920M's already, not really tempted by a third. I have a paper copies of operator, calibration, and service manual if anyone interested. regards, ben. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
Hi Ben, I am going to check this out today to find if it might be helpfull around here for my AC calibration. It has an error message: "Error Ur" so some fixing is going to be needed. On the back it says it's got Option 80, whatever that is. Charlie On 8/31/2014 5:37 AM, ben wrote: Hello all, Just a heads up. I noted there is a lonely Datron / Wavetek 4920M AC voltmeter for sale on ebay, starting at US$650 (ending in 1 day !). I have little idea of its true working state or not (picture shows it powered on). If fully working it would be a good buy for an AC voltmeter that is, I reckon, better than an HP 3458A. Only drawback with these models is the voltage input shell is always earthed, not floating. I have two of these 4920M's already, not really tempted by a third. I have a paper copies of operator, calibration, and service manual if anyone interested. regards, ben. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 732A and Prologix received
Hi Don, Your post and link are fine but I need to get some time today to look at it more carefully. I had two posts recently that were blank but since then all seems back to normal. Charlie On 8/31/2014 7:47 AM, Don@True-Cal wrote: Charlie, Did my reply to your question along with my lab temperature graph link come through? Just checking as there has been some issues with the posts. I don't like the "feature" where you don't see your own posts. Don -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Black Sent: Friday, August 29, 2014 3:44 PM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] 732A and Prologix received Hi Don, I'm a bit of trouble sending you this message for some reason. Maybe the third ti me is the charm. Thanks for sharing the graph a few days ago. My 3458A graphs look about the same except I only do voltage so far. I use NPLC 1000 which looks smoother but doesn't really have any additional useful info. I have been meaning to have my TEMP? servoed some time in the near future. My TEMP? runs about 37C at a room temp of 23C. Is your room temp a bit higher? Charlie On 8/29/2014 1:36 PM, Charles Black wrote: ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 732A and Prologix received
Hi Don, I'm a bit of trouble sending you this message for some reason. Maybe the third ti me is the charm. Thanks for sharing the graph a few days ago. My 3458A graphs look about the same except I only do voltage so far. I use NPLC 1000 which looks smoother but doesn't really have any additional useful info. I have been meaning to have my TEMP? servoed some time in the near future. My TEMP? runs about 37C at a room temp of 23C. Is your room temp a bit higher? Charlie On 8/29/2014 1:36 PM, Charles Black wrote: ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 732A and Prologix received
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Re: [volt-nuts] 732A and Prologix received
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Re: [volt-nuts] Fluke 5200A extender board.
Hi Ken, Nigel is setting you on the right track with Vectorbord. I have used them for the edge connectors over the years with good results. I don't know if you are able to use Digikey of not but they list a 3690-26 ($80) that will be easy to modify to work for your project. I probably shouldn't have said that since I dont know how long you need the card extendor to be. If it is long enough it is not hard to saw (or mill) it twice to get the proper number of pins. I have a small mill available so I would use it. If i had to use my table saw it would be more of a challenge but it can be done. I usuallydon't need to glue the connector since it is largely self supporting. If it is a bit too loose for you it is easy to glue a plastic strip or two on the connector face. If you really screw up the connector you can replace it with the one Nigel found. Just use heavy wire wrap wire for any "Adjustments". There are a few Vectorbord choices that would work for you. By the way, although Vectorbord is the correct spelling it is commonly spelled Vectorboard on the net. Charlie On 8/28/2014 3:22 AM, gandal...@aol.com wrote: Hi Ken, I don't know if it helps but there's a 43/86 edge connector offered here for 14USD, (12USD for 5+).. https://www.surplussales.com/ComputerAccess/con_edge.html Single and double sided PCBs with 0.1 inch spaced strips were quite common at one time as part of the Veroboard range, some with gold plated edge connectors and some quite large, and it's possible these too might turn up as surplus. Not ideal for taking the double sided connectors but easy enough to bodge, albeit a bit time consuming. I thought I had some of the larger boards amongst my old prototyping stock but can only find 32 way single sided at the moment so the others seem to have gone already. Regards Nigel GM8PZR In a message dated 28/08/2014 07:47:53 GMT Daylight Time, kgood...@iinet.net.au writes: Hi, The pin spacing on the card edge connectors is 0.1" (2.54 mm) and is a 43/86 dual row socket. I know what the extender looks like as I found one on ebay several months ago that had already sold for $50 (damm it!!) and I have been looking ever since, but it had a picture of it. It is a double sided pcb board that plugs into the female connector that is mounted vertically in the instrument and then rises up above the top of the instrument case where there is a female socket mounted horizontally so in effect the board now sits horizontally above the instrument whereas normally it sits vertically in the instrument. That way you have access to the board to take measurements, something you cannot do when the boards are in the instrument due to the close spacing of the various boards. As the 43/86 pin card edge connectors appear unobtainable I have sourced a 50/100 pin female connector that I can make do with, but I need either a 43/86 pin male card edge connector (which are also unobtainable) to make up an extender using cables as you have done, so the only option appears to be to make up a double sided pcb board with pads spaced at 0.1" centres on both sides and then either use it to terminate the cables to the female socket , or probably better make the pcb the same as the original extender and just use my 100 pin socket on that. That is why I was hoping someone may be able to photo copy the pcb board if they have an extender they do not want to sell. Thanks, Ken Goodhew. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 732A and Prologix received
My post on this thread earlier today seems to be lost (maybe the system change) so I am re-posting some of it (corrected) since it's apropos to the discussion. Anyone who has calibrated (CAL 0 anyway) a 3458A has enough information to deduce that lowest input short voltage is going to be a copper wire since the meter is set to zero volts during calibration using a heavy gauge (14 to 16) copper wire. This is very convenient since it is so easy to duplicate in the field and makes simple inexpensive test leads best for high precision measurements. In order for the 3458A to make full accuracy measurements (8 digit) NPLC must be set to 1000 (according to the User's Guide). If you use a lower NPLC value there is a table in the User's Guide that can be used to determine how accurate your measurements are going to be. Just for fun I ran several shorts for NPLC 1000 on my 3458A. It has been about a year since I clid my last CAL 0 so it was going to be interesting at least for me. The first shunt was my test "U' shaped shunt that I used for my last CAL 0. Note: STP = Shielded Twisted Pair. Calibration shunt-0.00021mv ± 10nV Equilibration time 5 minutes. 14 gauge per Calibration Manual. "U" heavy wire -0.00021mv ± 10nV Equil. time 5 minutes. Used the through holes in the Input banana posts only. Copper wire -0.00019mv ± 10nV NAPA PVC covered automobile wire at same contact points as CAL shunt Standard Ground Plate -0.00040mv ± 10nV Equil. time 5 minutes. Gold plated ground plate from my Datron 4910 Copper wire -0.00019mv ± 10nv Equil. time 2 seconds. Used the banana through holes. STP 2 meter test lead -0.00021mv ± 10nV Equil. time 2 seconds. M27500 24 gauge STP Tefzel insulation. Banana plugs -0.00021mv ± 30nV Equil. time 20 minutes. My best "Perfect" gold plated plugs with copper wire. Note that all my test shorts equilibrate to virtualy zero volts. There is almost no Seebeck voltage for any of my test shorts as long as the system is allowed to equilibrate. Equilibation times varied between less than 2 seconds up 20 minutes with longer times due to excessive thermal mass. Excessive thermal mass also caused some voltage instability. Charlie On 8/25/2014 6:54 PM, Don@True-Cal wrote: Why? Let me count the ways. You can never count on any Seebeck voltage to be immediately offset, there are far too many variables. Best example I can think of...why is there an Ohms Offset Compensation feature on any good high resolution DMM. 1) Try measuring a 1 or 10 Ohm resistor with your 3458A in 4-wire mode using inexpensive nickel-plated leads and even allow plenty of time for everything to thermally stabilize. Using Ohms Offset Compensation, enable and disable it and observe the difference. If the Seebeck voltages were all immediately offset, as you say, there would be no difference. But there most certainly is. Or simply, why is there a need for ohms offset compensation feature if all Seebeck voltages cancel each other out. Sure, nickel-plated is a horrible choice but if it all canceled, what difference would it make how bad is. 2) The cal lab workhorse calibrator is the 5700A/5720A. In between trips back to Fluke for full calibration, there is an interim external calibration procedure using the 732B, 742A-1 & 742A-10k. If someone used a set of gold-plated interconnects for this procedure, they would be laughed out of the lab and the calibrator would be useless until recalibrated properly. A set of 5440A-7002 (banana plug) cables comes with this calibrator (5440A-7003 spade lugs for 5720A) and recommended for the calibration procedure but other Beryllium Copper or pure Copper cables are also acceptable. 3) Lab air drafts will never allow true thermal symmetry around the DMM or DUT terminals. To convince yourself, place an oscillating fan several feet back from the DMM and DUT terminals and using the 1 or 10 Ohm setup from above, again with the nickel-plated leads, watch the variations. Sure the fan and the nickel-plated exaggerates the issue but it quickly dispels the notion that all the Seebeck voltages are canceled out. BTW, the plating layer temperature on a plated terminal will be somewhere between the temperature of the base metal and mating terminal it's connected to. This is not just theory, my 40+ years in the cal lab is driving my arguments but it never hurts to have physical-science on your side. Don Johnson -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Mike S Sent: Monday, August 25, 2014 11:03 AM To: volt-nuts@febo.com Subject: Re: [volt-nuts] 732A and Prologix received On 8/25/2014 11:02 AM, Don@True-Cal wrote: Silver or Gold plating on the terminal or wire will introduce the undesirable dissimilar metal properties, both at the plating junction and at the plating metal to DUT terminal. Why? Any Seebec
Re: [volt-nuts] 732A and Prologix received
I just realized that all my measurement tolerances are nV not pV. Sorry about not checking units first. Charlie On 8/25/2014 9:50 AM, Charles Black wrote: Hi Adrian, Although I have not used the Pomona spade lugs or a nano-voltmeter, my experience is consistent with yours otherwise. Anyone who has calibrated (CAL 0 anyway) a 3458A has enough information to deduce that lowest input short voltage is going to be a copper wire since the meter is set to zero volts during calibration using a heavy gauge (14 to 16) copper wire to short the top four input terminals. This is very convenient since it is so easy to duplicate in the field and makes simple inexpensive test leads best for high precision measurements. In order for the 3458A to make full accuracy measurements (8 digit) NPLC must be set to 1000 (according to the User's Guide). If you use a lower NPLC value there is a table in the User's Guide that can be used to determine how accurate your measurements are going to be. Just for fun I ran several shorts for NPLC 1000 on my 3458A. It has been about a year since I clid my last CAL 0 so it was going to be interesting at least for me. The first shunt was my test "U' shaped shunt that I used for my last CAL 0. Note: STP = Shielded Twisted Pair. Calibration shunt-0.00021mv +/- 10 pV Equilibration time 5 minutes. 14 gauge per Calibration Manual. "U" heavy wire-0.00021mv +/- 10pV Equil. time 5 minutes. Used the through holes in the Input banana posts only. Copper wire -0.00019mv +/- 10pV NAPA PVC covered automobile wire at same contact points as CAL shunt Standard Ground Plate -0.00040mv +/- 10pV Equil. time 5 minutes. Gold plated ground plate from my Datron 4910 Copper wire -0.00019mv +/- 10Pv Equil. time 2 seconds. Used the banana through holes. STP 2 meter test lead -0.00021mv +/- 10pV Equil. time 2 seconds. M27500 24 gauge STP Tefzel insulation. Banana plugs -0.00021mv +/- 30pV Equil. time 20 minutes. My best "Perfect" gold plated plugs with copper wire. Charlie On 8/25/2014 3:36 AM, acb...@gmx.de wrote: I have used the pomona spades, mainly to interface the low emf pomona banana cables to binding posts. I have stopped this, reasons being, they are large and worse, that the pomona spring loaded insulation tube that covers the banana plug conductor uses such a strong spring that slowly the plug works its way out of the spade. this btw also happend to me when I used the pomona low emf binding posts together with the pomona low emf banana cables. overall I m not happy with these. so, due to lack of options, I changed to self-made twisted shielded pair of high grade teflon/kapton silver plated copper cable with gold plated copper spades (crimped). I use them not only with the 3458a but also with nanovolt meters. these have higher resolution and accuracy in low level measurements than the 3458a. emf voltages were never an issue with these cables if properly used. I have posted some results doing 34420a stabilty measurements on the pmel forum, and the results are convincing (purpose was actually not to test the cables but the stability of the 34420a, but the emf issue is a part of this of course. we use the 34420a to do low voltage precision measurements on thermal converters where the full scale signal sometimes is 1mV). that btw also relates to don's statements below, I do not concurr with his comments about copper telurium as cable and spade material and so on. this material, as stated here many times, is used because it is machinable, for copper spades one would not use it. the 34420a factory cable uses copper cable and copper spades, not telurium-copper. if there was a problem, it would be worse with the 34420a than with the 3458a because of its low level ranges. and again, I have not seen any problems in a chain of (output to input): 1.copper-tellurium post from e.g. 8 digit calibrator 2.crimped copper spade, gold plated 3.silver plated tsp copper cable 4a.crimped copper spade to copper-tellurium post or 4b.soldered copper connector(34420) my consistent results over more than a year using them. Gesendet: Montag, 25. August 2014 um 06:33 Uhr Von: "Orin Eman" An: "Discussion of precise voltage measurement" Betreff: Re: [volt-nuts] 732A and Prologix received On Sun, Aug 24, 2014 at 1:46 PM, Don@True-Cal wrote: Randy & all, You have correctly concluded that some (maybe not all) of your measurement problem is thermal EMF being added or subtracted in series within your measurement interconnect. This thermal EMF is generated at the junction of dissimilar metals when accompanied with thermal gradients between the test lea
Re: [volt-nuts] 732A and Prologix received
Hi Adrian, Although I have not used the Pomona spade lugs or a nano-voltmeter, my experience is consistent with yours otherwise. Anyone who has calibrated (CAL 0 anyway) a 3458A has enough information to deduce that lowest input short voltage is going to be a copper wire since the meter is set to zero volts during calibration using a heavy gauge (14 to 16) copper wire to short the top four input terminals. This is very convenient since it is so easy to duplicate in the field and makes simple inexpensive test leads best for high precision measurements. In order for the 3458A to make full accuracy measurements (8 digit) NPLC must be set to 1000 (according to the User's Guide). If you use a lower NPLC value there is a table in the User's Guide that can be used to determine how accurate your measurements are going to be. Just for fun I ran several shorts for NPLC 1000 on my 3458A. It has been about a year since I clid my last CAL 0 so it was going to be interesting at least for me. The first shunt was my test "U' shaped shunt that I used for my last CAL 0. Note: STP = Shielded Twisted Pair. Calibration shunt-0.00021mv +/- 10 pV Equilibration time 5 minutes. 14 gauge per Calibration Manual. "U" heavy wire-0.00021mv +/- 10pV Equil. time 5 minutes. Used the through holes in the Input banana posts only. Copper wire -0.00019mv +/- 10pV NAPA PVC covered automobile wire at same contact points as CAL shunt Standard Ground Plate -0.00040mv +/- 10pV Equil. time 5 minutes. Gold plated ground plate from my Datron 4910 Copper wire -0.00019mv +/- 10Pv Equil. time 2 seconds. Used the banana through holes. STP 2 meter test lead -0.00021mv +/- 10pV Equil. time 2 seconds. M27500 24 gauge STP Tefzel insulation. Banana plugs -0.00021mv +/- 30pV Equil. time 20 minutes. My best "Perfect" gold plated plugs with copper wire. Charlie On 8/25/2014 3:36 AM, acb...@gmx.de wrote: I have used the pomona spades, mainly to interface the low emf pomona banana cables to binding posts. I have stopped this, reasons being, they are large and worse, that the pomona spring loaded insulation tube that covers the banana plug conductor uses such a strong spring that slowly the plug works its way out of the spade. this btw also happend to me when I used the pomona low emf binding posts together with the pomona low emf banana cables. overall I m not happy with these. so, due to lack of options, I changed to self-made twisted shielded pair of high grade teflon/kapton silver plated copper cable with gold plated copper spades (crimped). I use them not only with the 3458a but also with nanovolt meters. these have higher resolution and accuracy in low level measurements than the 3458a. emf voltages were never an issue with these cables if properly used. I have posted some results doing 34420a stabilty measurements on the pmel forum, and the results are convincing (purpose was actually not to test the cables but the stability of the 34420a, but the emf issue is a part of this of course. we use the 34420a to do low voltage precision measurements on thermal converters where the full scale signal sometimes is 1mV). that btw also relates to don's statements below, I do not concurr with his comments about copper telurium as cable and spade material and so on. this material, as stated here many times, is used because it is machinable, for copper spades one would not use it. the 34420a factory cable uses copper cable and copper spades, not telurium-copper. if there was a problem, it would be worse with the 34420a than with the 3458a because of its low level ranges. and again, I have not seen any problems in a chain of (output to input): 1.copper-tellurium post from e.g. 8 digit calibrator 2.crimped copper spade, gold plated 3.silver plated tsp copper cable 4a.crimped copper spade to copper-tellurium post or 4b.soldered copper connector(34420) my consistent results over more than a year using them. Gesendet: Montag, 25. August 2014 um 06:33 Uhr Von: "Orin Eman" An: "Discussion of precise voltage measurement" Betreff: Re: [volt-nuts] 732A and Prologix received On Sun, Aug 24, 2014 at 1:46 PM, Don@True-Cal wrote: Randy & all, You have correctly concluded that some (maybe not all) of your measurement problem is thermal EMF being added or subtracted in series within your measurement interconnect. This thermal EMF is generated at the junction of dissimilar metals when accompanied with thermal gradients between the test lead and device terminals. You have to eliminate both the dissimilarity of the metal junctions as well as minimize the thermal differences. The terminals of the 3458A as well as the 732A are Beryllium Copper so you want to use the same test l
Re: [volt-nuts] 732A and Prologix received
Hi Randy, You can use the NPLC command to change the A/D converter's'integration time. Set it to 1000 if you want full resolution. It sets the hp3458a's NMR. Charlie On 8/24/2014 6:04 PM, Randy Evans wrote: Bill, I am trying to figure out the MATH function without much success. I input the sequence you said (I looked up the instructions to understand what you did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS 40;TRIG 4;TRIG; and it shows up on the display when I input BLUE F1. I hit ENTER and it takes the 40 measurements and the MATH symbol shows on the display during the measurements. After the SMPL symbol no longer blinks I hit MATH 2 and I get a MATH ERR symbol on the display. I tried it a couple of times and the same result so I am doing something wrong. Is there a better source for explaining how to do front panel masurements than the User Guide, which seems oriented at programming automatic rather than manual measurements. Randy On Sun, Aug 24, 2014 at 4:46 PM, Bill Gold wrote: Randy: The MATH function is accessible from the keypad. I don't have an IEEE interface right now that works. You can also program the numeric keypad keys to have preprogrammed functions. DEFKEY I have made my own "low thermal" measurement leads from Pomona #4892 banana plugs and Belden #9272 wire. Why 9272, because it was handy at the time. It is tin plated copper, shielded twisted pair 20 ga. I have plans to do custom cables with 16 ga. bare copper wire that I will twist and then put a braided shield over it. I simply cannot find what I want so I will build my own cable. I have done something like this before and it worked fine. When I get a "round toit". I have 6 ea. Pomona 1756-48 spade lug low thermal leads that I have used in the past to verify my homemade "low thermal" leads as described above. Frankly I cannot see any difference between using the 1756 cables and my homemade cables once I give them a few minutes for the thermals to go away. As far as I can tell and measure the differences, if any, are below 0.1 ppm at 10 volts. Since the 10 volt, 1.0 volt and 1.018 volt outputs on the 732A are all adjustable you may be seeing a misadjusted 1 volt from the 732A. As far as the instability of the readings it is hard to determine which is causing the problem. I have programed (DEFKEY) a numeric keypad key #1 with the following code. "MATH 14;NRDGS 40;TRIG 4;TRIG ;" So what this does is set the MATH to "Statistics" (store high reading/low reading/ and mean of the readings) in the registers, the number of readings to "40", the trigger to "hold" (which keeps the meter from triggering until I press "ENTER" and then trigger the sequence of 40 readings when I push the "ENTER" button. You can do all of this manually from the keypads but since I use this sequence a lot I have preprogrammed it. This is after I set digits to "8" and PLC to 100. Once those 40 readings are finished then you can access the various MATH statistic registers, using the menu, by entering "MATH" and then a 2 for low, a 4 for mean, and 13 for high. Of course you could do all of this through the IEEE also. The 3458A has a very rich set of measurement commands. I am still learning all of them. It depends upon what I am trying to accomplish. Since the 1.018 and 1.0 volt outputs are passive and derived from resistive dividers from the 10 volt, I don't see how they could contribute to the varying readings you are measuring. I think I would put a short on the input of the 3458A and manually set the range to 1 volt and then observe the variations that way without the 732A involved. When I do this I see a variation from low reading to high reading of 0.125 uVolts and then another 40 I get 0.155 uVolts. This is without the GUARD connected to the low side of the measurment terminals, GUARD connected doesn't seem to affect the readings. So that is the base noise of the 3458A without the 732A, somewhere below .2uVolts. When hooked up to the 732A 1.0 volt output I got a variation of 0.159 uVolts using the same 40 reading method above. I would use this to determine where your problem might exist. Just having the meter input shorted will point you in the right direction. Meter, cables or 732A. Sorry for the long dissertation. Friends get mad at me for being so detailed sometimes. Bill - Original Message - From: "Randy Evans" To: "Discussion of precise voltage measurement" Sent: Sunday, August 24, 2014 7:22 AM Subject: Re: [volt-nuts] 732A and Prologix received Bill, I have convinced myself that the problem I an seeing is due to thermals. If I move the cables (with gold-plated banana plugs) using a small towel rather than letting my hand touch the plugs, it is much more stable. If I then hold the banana plug with my hand after the reading has stabilized, the reading drifts rapidly upward. I am trying to check the stability of the reading but I haven't figured out t
Re: [volt-nuts] 732A and Prologix received
Bill, I have never been able to use banana plugs of any kind, with my 3458A, due to their excessive thermal mass. I use 24 gauge wires to make a twisted pair by hand with no connectors for precision voltage work. As brought out in an earlier post by acbern, it doesn't matter about plating or solder at least as long as your twisted pairs are made from the same wire so the thermocouples balance out. I am a big fan of M27500 shielded twisted pair wire for everyday use. It is durable, heat resistant and capable of very low voltage use. The insulator is Tefzel and the plating used to be silver but may be something else now. It take a few minutes work for proper termination but it can be done for free. I tend to use a lot of the 24 gauge M27500 STP wire since it is fast to come to temperature, flexible and durable enough to last quite awhile. eBay always has quite a few small lengths available and Sierra Nevada Products has a bunch of it. Sierra Nevada Products says that it is Teflon but I think it may be Tefzel. I can help with termination instructions if wanted. Charlie On 8/24/2014 7:22 AM, Randy Evans wrote: Bill, I have convinced myself that the problem I an seeing is due to thermals. If I move the cables (with gold-plated banana plugs) using a small towel rather than letting my hand touch the plugs, it is much more stable. If I then hold the banana plug with my hand after the reading has stabilized, the reading drifts rapidly upward. I am trying to check the stability of the reading but I haven't figured out the MATH function yet. I assume this is a programmed function using GPIB only? The stability I am seeing by manually recording readings (using NLPC of 100 and 1000) is much greater than what you are measuring on your system. Not sure how to ascertain if it's the 3458A or the 732. The value of the readings are very different between the two - the 3458 reads about 50 uV high on the 10 V output and about 12 uV low on the 1V output. Rather large differences (this is after an ACAL). I need to find some better cables to make sure the errors are not due to thermals again. Randy On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold wrote: Randy: I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and they will fit perfect. Power Sonic PS-640, Genesis NP4-6, Panasonic LC-R064R5C and others that are in this size and package. Order from one of the usual electronics distributors like Allied, Mouser, Digikey. This is a very common battery as it is used in a lot of "EXIT" signs so they are lighted when the power goes out. I don't see how the 12V 7AH will fit as they are too large. I guess you could use a 12V 5AH (PS1250) as it is the same size as 2 x 6 volt 4 AH but the terminals are in the wrong place so you will have to "nibble" out the aluminum plate that holds them in the 732A battery pack. You have to be careful if you use the 12v 5AH as you will have 4 extra battery connection leads to deal with and connect correctly. I would stick with the 6V 4AH. New batteries will last around 12 to 14 hours before the "CAL" light goes out when AC power is not applied. So shipping to Cal Lab can be a problem if it is a distance away, or you have to use a shipper like UPS or FEDEX and you ship the night before and then use their "Morning delivery" and the Cal Lab is expecting your 732A. Same on the way back to you. Of course you could always strap another battery on the 732A and hook it up to the "ext power" plug to last longer. I have seen it done. The issue is to get the Cal Lab to charge the extra battery before they ship the 732A back to you. When you remove and work on the battery pack always have the AC power plugged in. The "CAL" led will stay on because the 18.6 v regulated supply is working. The "CAL" light is to indicate that power has not been lost to the Reference Amp or other associated circuits. When the raw supply (battery) voltage drops below about 21 volts the "CAL" light will go out. Below that voltage the heater circuits will not work correctly and the 18.6 volt regulated supply will not regulate. The requirement is that the Reference Amp be kept "alive" at all times to maintain the output voltage that was measured at the time of the most recent Calibration or Certification. When the semiconductor junctions are unbiased and cool off when power is lost, and then power is restored the result will be a different 10 volts than before the power failure. My experience is that after all of the years that these units have been powered up, this won't happen and when power is lost and then restored, even months later, the 732A will come back to almost exactly the same 10 volts as when they lost power, usually with in 0.2 PPM after 24 hours of "warm up". What type of hookup leads are you using when measuring the 1 volt output? What is the PLC set to? I always use 100 PLC to measure this. If you don't have "low thermal" connection leads you can expe
Re: [volt-nuts] HP3458A CAL ram data dumper program
Hi Mark, I had success using your HP3458.exe on my HP3458A! I just backed up my CAL data a few minutes ago. I have been interested in doing a backup for several years but kept putting off buying the GPIB to USB adapter. I have been using a NI GPIB-ENET/100 for some years now and so your program was a way for me to backup CAL ram at no cost. The only preparatory steps I needed was to test my GPIB connectivity with NI Measurement & Automation Explorer's Communicate with Instrument function. Then I Reset the 34358A and set END to Always. I had NI's I/O Trace on the whole time just to keep track of everything. I think the NI 488 software is a free download. Thanks for all the work you did! Charlie On 8/21/2014 9:42 PM, Mark Sims wrote: The program outputs a 2kB (or 2 x 32kB) binary ROM image files files along with a couple of ASCII format files of the data. 2kb for CAL ram and 32kb for DATA ram (probably not needed, but it can dump the data RAM chips). The binary files have the extension .hi and .lo (CAL ram data is only in the high byte of the memory space). ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] RE "new" 3458A
It faster to use alphabetical menu system. Also I forgot to mention that
if you want to recall a recent command just hit the grey button and then
the enter button ("Recall"). This can be done over and over to bring
back older commands.
Charlie
On 8/18/2014 1:46 PM, Randy Evans wrote:
I finally found it after I realized I had to select the LONG MENU first.
Thanks,
Randy
On Mon, Aug 18, 2014 at 7:27 AM, Charles Black
wrote:
Hit the grey key in the "FUNCTION/RANGE" key block. Then hit "T" (light
grey marking) in the "MENU" key block Then hit down arrow twice in the
"FUNCTION/RANGE" key block. You will now have TEMP? on the display. Then
hit the "Enter" key in the "NUMERIC/USER" key block. Now you should see the
TEMP? value in degrees Celsius.
Charlie
On 8/17/2014 8:48 PM, Randy Evans wrote:
Can someone explain to me how to read the internal temperature using the
front panel TEMP? command. I have played around but I am doing something
wrong.
thanks,
Randy
On Sun, Aug 17, 2014 at 5:13 PM, Randy Evans
wrote:
That worked! Now it reads 000.00030mV. So far it looks good except for
the display.
Thanks,
Randy
On Sun, Aug 17, 2014 at 12:54 PM, Bill Gold wrote:
You need a comma "," between the "0" and the "3458". So blu C"CAL
0,3458" "Enter".
See pg. # 64 of the CAL Manual for the syntax.
Bill
- Original Message -
From: "Randy Evans"
To: "Discussion of precise voltage measurement"
Sent: Sunday, August 17, 2014 12:25 PM
Subject: Re: [volt-nuts] RE "new" 3458A
Bill,
You are very helpful and I really appreciate it.
I entered BLUE-C-03458 and I still get the ERR message (106, "OUT OF
RANGE
-- CAL secured"). That would be consistent with what you are saying.
I
guess its no reason to panic yet.
I'm not sure how to use the SECURE command. I guess it's time to open
it
up but I will probably have to get some PosiDrive screwdrivers.
Thanks,
Randy
On Sun, Aug 17, 2014 at 11:39 AM, Bill Gold
wrote:
Randy:
You are doing a ZERO calibration on the meter rather than a ACAL.
You
have to give it a password after the "0" and then it will do the ZERO
calibration. Usually the password is "3458" and comes from the
factory
that
way. But someone could have changed it in the past. You can do this
from
the front panel menu using the SECURE command. But there is a jumper
inside
the 3458A which disables the request for a password so that you can do
any
CAL or reset the password to what you want. So everything is working
as
expected. The jumper is JM600 on the outguard processor board 66505
or
66515 on the left of the meter inside. Try "3458" first as most are
set
to
this password. Read the Calibration Manual pg. #8 for how to get
inside
of
the meter. You will need two sizes of a PosiDrive type screwdrivers
to
accomplish this. Again in the Cal Manual.
Bill
- Original Message -
From: "Randy Evans"
To: "Discussion of precise voltage measurement"
Sent: Sunday, August 17, 2014 11:22 AM
Subject: Re: [volt-nuts] RE "new" 3458A
Bill,
I installed the U-short and executed the BLUE-C-0 front panel
command
and
I
get an ERR on the display. I assume this is not good. Did I do
this
correctly?
Thanks,
Randy
On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold
wrote:
Randy:
Look at page #23 of the 3458A Calibration Manual. Make
yourself
a
"4
Terminal Short" as shown and put it in as shown.
Before I did an ACAL I had around -000.00025 mVDC. After
ACAL I
now
read +000.2 mVDC. I did the "CAL 0" myself so I would expect
that
the
meter should return to a low value, and it does. I do get a
variation
of
+/- 30 nVDC using 100 PLC and just observing the variations. As I
remember
I have never seen a spec on the ZERO stability over temperature.
If I turn on the MATH function and then do 40 measurements
with
100
PLC
the statistics show:
Low reading-70 nVDC
Mean reading -28 nVDC
High reading+3.5 nVDC
Total Variation73 nVDC
So that correlates with my visual observation of 60 nVDC.
After
an
hour
the room had gone up around 1 degree C. Then I observed
-000.00023
mVDC.
After another ACAL the reading was again +000.2 mVDC. This
particular
meter has a negative tempco as the room temp goes up.
Obviously do an ACAL before any precision measurements
requiring
low
nanovolts.
Go to the Keysight website and go to "Technical Support" and
choose
"Parts". Then enter in the "Part Number" "03458-66517" which is
the
replacement "03458-66507" assembly and you will see the
replacement
part
number on the right hand side. Click on th
Re: [volt-nuts] RE "new" 3458A
Hit the grey key in the "FUNCTION/RANGE" key block. Then hit "T" (light grey marking) in the "MENU" key block Then hit down arrow twice in the "FUNCTION/RANGE" key block. You will now have TEMP? on the display. Then hit the "Enter" key in the "NUMERIC/USER" key block. Now you should see the TEMP? value in degrees Celsius. Charlie On 8/17/2014 8:48 PM, Randy Evans wrote: Can someone explain to me how to read the internal temperature using the front panel TEMP? command. I have played around but I am doing something wrong. thanks, Randy On Sun, Aug 17, 2014 at 5:13 PM, Randy Evans wrote: That worked! Now it reads 000.00030mV. So far it looks good except for the display. Thanks, Randy On Sun, Aug 17, 2014 at 12:54 PM, Bill Gold wrote: You need a comma "," between the "0" and the "3458". So blu C"CAL 0,3458" "Enter". See pg. # 64 of the CAL Manual for the syntax. Bill - Original Message - From: "Randy Evans" To: "Discussion of precise voltage measurement" Sent: Sunday, August 17, 2014 12:25 PM Subject: Re: [volt-nuts] RE "new" 3458A Bill, You are very helpful and I really appreciate it. I entered BLUE-C-03458 and I still get the ERR message (106, "OUT OF RANGE -- CAL secured"). That would be consistent with what you are saying. I guess its no reason to panic yet. I'm not sure how to use the SECURE command. I guess it's time to open it up but I will probably have to get some PosiDrive screwdrivers. Thanks, Randy On Sun, Aug 17, 2014 at 11:39 AM, Bill Gold wrote: Randy: You are doing a ZERO calibration on the meter rather than a ACAL. You have to give it a password after the "0" and then it will do the ZERO calibration. Usually the password is "3458" and comes from the factory that way. But someone could have changed it in the past. You can do this from the front panel menu using the SECURE command. But there is a jumper inside the 3458A which disables the request for a password so that you can do any CAL or reset the password to what you want. So everything is working as expected. The jumper is JM600 on the outguard processor board 66505 or 66515 on the left of the meter inside. Try "3458" first as most are set to this password. Read the Calibration Manual pg. #8 for how to get inside of the meter. You will need two sizes of a PosiDrive type screwdrivers to accomplish this. Again in the Cal Manual. Bill - Original Message - From: "Randy Evans" To: "Discussion of precise voltage measurement" Sent: Sunday, August 17, 2014 11:22 AM Subject: Re: [volt-nuts] RE "new" 3458A Bill, I installed the U-short and executed the BLUE-C-0 front panel command and I get an ERR on the display. I assume this is not good. Did I do this correctly? Thanks, Randy On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold wrote: Randy: Look at page #23 of the 3458A Calibration Manual. Make yourself a "4 Terminal Short" as shown and put it in as shown. Before I did an ACAL I had around -000.00025 mVDC. After ACAL I now read +000.2 mVDC. I did the "CAL 0" myself so I would expect that the meter should return to a low value, and it does. I do get a variation of +/- 30 nVDC using 100 PLC and just observing the variations. As I remember I have never seen a spec on the ZERO stability over temperature. If I turn on the MATH function and then do 40 measurements with 100 PLC the statistics show: Low reading-70 nVDC Mean reading -28 nVDC High reading+3.5 nVDC Total Variation73 nVDC So that correlates with my visual observation of 60 nVDC. After an hour the room had gone up around 1 degree C. Then I observed -000.00023 mVDC. After another ACAL the reading was again +000.2 mVDC. This particular meter has a negative tempco as the room temp goes up. Obviously do an ACAL before any precision measurements requiring low nanovolts. Go to the Keysight website and go to "Technical Support" and choose "Parts". Then enter in the "Part Number" "03458-66517" which is the replacement "03458-66507" assembly and you will see the replacement part number on the right hand side. Click on that and you will get the information about the exchange program and so on. Looks like you can just order this part online and pay for it with a credit card, but you have to create or use an existing login account. I needed a new display a few years ago. At that time you could order just the display for around $80. Being extremely good at removing and then inserting and soldering I ordered the part. The problem was that the spacing from top to bottom of the pins had changed. It went from around 1.3 inches to around 1.5 inches. So I had to bend the pins to fit my display board and then get something like 72 pins into the holes on the PC Board. It took hours. This change is probably why HP/Agilent/Keysight doesn't let you jus
Re: [volt-nuts] New HP3458A
Randy, I have not been able to do accurate work with banana plugs. Too much thermal mass. For best results use copper wires into the cross holes of the banana jacks or small gold plated copper spade lugs crimped on the ends of the test leads. Cheap at Radio Shack. Both work fine. Remember to do an ACAL every time you want accuracy. I think my 3458A is about +5 PPM/C for four wire resistance (10K ohm) on differences of Temp?. Also clean your air filter and record the Temp? after so you know when to clean it again. If you try to use high impedance resistance standards (L&N Cheap ones) they will not measure correctly unless DELAY = 10 seconds on my system. Charlie On 8/15/2014 6:39 PM, Randy Evans wrote: I would like to thank everyone that replied to my query on what to look for in my "new" HP-3458. I did find that the AUTO ZERO button does work fine, thanks to Bill's comments. I had looked in the manual, just not far enough. The display is still perfectly readable but i would like it to be "perfect". I am particularly interested in the exchange display for $272 (better than $700 for a new one, as Todd suggested). Does someone have a contact number at Keysight that I could call (my experience is that one can spend a lot of time calling around until the right person is finally found). I certainly need to figure out how to copy and replace the NVRAM - I lost the calibration on my Datron 1082 by not realizing the memory backup battery died and now I need to calibrate it myself (the HP3458A should make that doable, I hope). Any suggestions would be greatly appreciated. I believe it has been covered before on Volt-Nuts and I need to go through the past discussions to find it. One question I have for the group is what should the display typically show with the input shorted? I see a reading of about -.0025 mV. That seems rather high. I tried several different banana cables (gold plated, tin plated) used to short the input terminals to see if thermocouple effects might be responsible but there was no change in the reading. Still learning. Thanks, Randy On Fri, Aug 15, 2014 at 8:06 AM, Jason Watson wrote: I've also seen excessive Guard to Low leakage when varistor RV501 has gone bad (it's located on the front/rear switch pcb and it's possible to replace it while leaving the circuit board in place if you are careful). HP/Agilent/Keysight Part number is 0837-0196, cross referenced to a Harris Corp. V430MA3A. On Fri, Aug 15, 2014 at 10:46 AM, Stephen Grady wrote: Randy, I have come across a few 3458A's that had leakage between Guard and Low when te guard is in external guard position. This was due to a leaky external guard switch and/or leaky front rear switch. This can be quickly determined by measuring resistance between guard and low with guard external. This normally in not an issue except when you are using 3458A to measure voltage with low above earth potential say in a bridge the guard low leakage will be loading other arm of the bridge. Kind Regards, Steve Grady Sydney, Australia -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Randy Evans Sent: Friday, 15 August 2014 1:22 PM To: volt-nuts@febo.com Subject: [volt-nuts] New HP3458A I picked up a used HP3458A today, which I needed for some precision DC measurements i need to make. It passes all the self tests and the Auto Cal but is there any thing else I can check ( I have a 14 day RR). It reads a 10V standard I made within a few tens of ppm, but it's not a 732A but that is at least comforting. It also reads an ESI 10Kohm standard resistor dead on. The only problem is that the display has some faint pixels in some locations, with three in the second row for every digit location dead. Likely a pixel driver I would think. I am not too familiar with it yet but I noticed when I push the auto zero button, the display has a blinking square until I hit a measurement mode button; e.g., DCV, ACV, OHM, etc. Is this normal? Regards, Randy Evans ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nu
Re: [volt-nuts] A Fluke 732A: Return it or keep it?
Hi Roy, I would like to second Todd's advice about leaving the Fluke 732A's output voltage adjustment alone. You already have stable outputs and 24 microvolts high is very acceptable. My Datron 4910 (four output supply) has predictable digital output level settings that doesn't have any luck involved so it is a better candidate for resetting the standards than the Fluke 732A. I had Fluke reset them last calibration because I had just repaired the Datron 4910 and my voltages were all over the place but stable. Also I would expect your Fluke 732A to about as temperature stable as my Datron 4910. In my experience my 3458A needs to be at 23C to calibrate. Also it should have the fan filter freshly cleaned and record the 3458A's internal temperature. I have recorded (over several days) each Datron 4910 output with my 3458A and a switch and can say that the Datrons are temperature stable but not my 3458A. Charlie On 6/12/2014 7:54 AM, Bill Gold wrote: Roy: I use a ( General Cement ) GC 8276 adjustment tool to make the pot adjustments in the 732A. I use the end that has the recessed metal blade. The pots are about 3.5 inches back from the front panel. It sometimes is very difficult to engage the tool slot in the pot. It helps to look through the front panel hole with a small flashlight and observe the position of the slot in the pot ( i.e. 9, 10, 11 o'clock for example ). Then when you insert the adjustment tool you can get close to the point when you can engage the adjustment pot. Sometimes it will seem impossible to engage the tool into the slot, but with patience it can be done. Once you do engage the pot do whatever adjustment you want, don't pull the tool out, just leave the tool engaged with the pot so that if you want to make another small change you won't have to go through the same problem of trying again and again to engage. I have found that turning the pots may cause a drift which will show up days later due to the pot being "dirty" or whatever. So what I usually do is to turn the pot back and forth over several revolutions so that I can "clean" the contact wiper. I usually make an initial adjustment and then turn the pot about 1/32 of a turn in the opposite direction just to relieve any "stress" that might be there and cause a small change in the output voltage. I usually have very good results with these methods. But I will agree with Joe that sometimes it is better just to leave things alone and just use the known offset from 10 volts when checking or doing cals. Bill - Original Message - From: "Todd Micallef" To: "Discussion of precise voltage measurement" Sent: Thursday, June 12, 2014 7:20 AM Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it? Roy, The 732A uses the 3059Y-1-101 type cermet pot for the 10V adjustment. You can use a simple plastic tweaking tool for adjustment. I believe you will need a fairly long tool. You can shine a light into one of the other holes to see the orientation of the pot. However, many people may prefer to leave the pot as is and just record the readings. It is going to drift anyway and won't stay adjusted for long. The drift may worsen once the pot position has changed too. I have adjusted mine, but only after the broken pots were replaced. Todd On Thu, Jun 12, 2014 at 9:57 AM, R.Phillips wrote: Hi Joe Sorry if I am retracing steps, but I have recently had my 3458A restored/recal'd by Agilent - its good to have it back. I also have a Fluke 732A which I can now check. Currently it is 10.24 volts, I now feel confident to trim it to the 3458A. I have tried to see the trimmers in each of the three holes - they appear to be some way within, and I am wondering if you could confirm the type of pot. that is used and just how long a trimming device is required. Is this a special tool only available from Fluke ? Regards Roy Phillips. -Original Message- From: J. L. Trantham Sent: Saturday, March 08, 2014 10:09 PM To: 'Discussion of precise voltage measurement' Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it? Charles, What size batteries did you use for your external pack and where are you located? In other words, how long can your external battery pack 'survive' keeping the 732A 'hot'? Is the external pack recharged at Fluke or does it have to make a round trip on the initial charge? Once I am convinced my unit is stable (which will probably be another six months or so, after I get my 3458A's re-calibrated by Agilent), I hope to be able to send it to Fluke for calibration. Fluke made a transit case (732A-7002) and a Battery Charger and Auxiliary Battery Case (732A-7003). However, I have never seen a picture of either of these. Does anyone have any information on these? How did you make your case? Did you include a charger? Combination of battery pack and shipping container or separate battery pack and shipping container? I was thinking of bui
Re: [volt-nuts] Fluke 845AB / 845AR neon bulb xref
Hi Christopher, I used some look alike NE-2's from ebay and they worked fine. Just search for ne2. Good luck! Charlie On 11/6/2013 2:34 AM, Christopher Brown wrote: So, working on a couple of 845s. The AR is a franken unit assembled from the parts of 2 damaged units. Works well, but intermittently, both neons are very weak. The AB was working well after cleaning up the leaking battery mess, and recapping but one of the bulbs failed. Looking at the original manual and a 1990 update I get NE-2U AND Lamp, NEON, 105-125V, 0.7MA, Wire Leads A9A-1 Cannot seem to find direct or xref Mouser show a Chicago Miniature A9A but no A9A-1 and A9A is 65VAC/90VDC NE-2U seems to cross to A3C, but cannot find A3C and A3C specs seem to indicate 1.9ma Can anyone help with the correct spec, xref to current part and supplier? ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] vSolartron7081 rom reading
MK, All you need to do is unplug the jones plug where the key wiring goes to the circuit board. No need to do any wiring! Charlie On 1/15/2013 5:00 PM, J. L. Trantham wrote: MK, Where are you? If you can't get a key made, I can probably send you one. IIRC, you can 'activate' the key by removing a wire from the key switch. That places it in 'CAL' mode. The schematic easily demonstrates this. I don't think it was 'shorting' the two switch wires. Of course that requires you to remove the top of the meter. Joe -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of m k Sent: Tuesday, January 15, 2013 4:30 PM To: volt-nuts@febo.com Subject: Re: [volt-nuts] vSolartron7081 rom reading I just noticed a gotcha, I need to set the key to calibrate before I may issue those commands, I guess I need a key. I have printed off the photo and measurements someone on this board did, now to get to a key shop... M K From: david.partri...@perdrix.co.uk To: volt-nuts@febo.com Date: Sun, 13 Jan 2013 17:14:07 + Subject: Re: [volt-nuts] vSolartron7081 rom reading If all you want is to save the calibration factors, just issue CALIBRATE,DUMP command To refresh the EAROM calibration factors, issue CALIBRATE,REFRESH - barring component failure that should be good for another ten years or so. You can also display the NVM contents with the MONITOR command, but NOT re-write them. The only way that I am aware of that will write the caibration constants if they have been lost is to run a full calibration. Again all this in chapter 8. I don't know which ROM programmers that can read or write the ER3400 (just ignorance - there may be loads). Regards, David Partridge -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of m k Sent: 13 January 2013 16:57 To: volt-nuts@febo.com Subject: Re: [volt-nuts] vSolartron7081 rom reading Hi David, well it is currently working and close to calibrated as far as I can tell. But I want to get those calibration factors saved before it dies on me. Last calibrated 2008, and well down on drift by now. I get a diurnal 0.14 microvolt drift with a shorting plug that stays on when not in use. a drift of about 0.1 microvolts in about 3 weeks. Nothing else to confirm anything else as I have only just got it chatting out through the rs232. I will have to buy something to read them with. M K ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Fwd: Public Health Update: novel Corona virus update
Original Message
Subject: Public Health Update: novel Corona virus update
Date: Fri, 05 Oct 2012 06:37:53 -0700
From: Frank James MD [1]
To: San Juan Medical Providers [2]
Much is still unknown and this virus does not appear to be easily
transmitted from person to person. I found this summary of what we know
so far and will pass it along incase your patients ask about it or in
the unlikely event that this becomes a more important issue. Millions
of people travel to Mecca this time of year and if it were more easily
transmissible there would be potential for further spread.
Frank
Frank James MD
Health Office
San Juan County
Novel Coronavirus in UK and Saudi Arabia
By Amesh A. Adalja, MD, FACP
Since the deadly outbreak of SARS and the discovery of its etiological
agent, the SARS Coronavirus (SARS-CoV), there has been a heightened
awareness that coronaviruses cause severe transmissible disease, a far
cry from the common cold they were exclusively linked to in the past.
From 2003 to 2011, 2 new human coronaviruses have been discovered, both
of which caused mild illness.^1 However, in 2012, a third new human
coronavirus (HCoV) was discovered and was sequenced at Erasmus Medical
Center (EMC) in the Netherlands. The new virus, designated HCoV-EMC, is
responsible for 2 severe cases in England and Saudi Arabia, 1 of which
was fatal.^2
Genus Coronaviruses That Infect Humans
The Coronavirus genus contains several viruses that are known to infect
humans. The first human coronavirus, HCoV-229E, was isolated in 1965,
followed soon after by the isolation of HCoV-OC43. The eventual
discovery of other coronaviruses that infect other animal species led
to the division of the animal and human coronavirus into 3 groups
(1-3). These groups have subsequently been split into
subgroups.^1 HCoV-EMC is in the 2c group, where it clusters with 2
coronaviruses of bats. The classification of human coronaviruses is
summarized below.^1,2
Group Viral strains
1b HCoV-NL63
2a HCoV-OC43, HCoV-HKU1
2b SARS-CoV
2c HCoV-EMC
HCoV-EMC Cases
Thus far, 2 cases of HCoV-EMC infection have been confirmed. The first
case, which was fatal, occurred in June in a 60-year-old man in Saudi
Arabia; the second case occurred in a 49-year-old Qatari man who
traveled to Saudi Arabia and is currently being treated in England.
From early case descriptions, it appears pneumonia is the primary
manifestation of the disease. The WHO has published a case definition
(Figure 1). It appears that the disease has an incubation period of up
to 10 days and that it is not easily transmitted between humans,
although full airborne isolation is recommended. As with all
coronaviruses, no specific treatment is available.^2
Figure 1: WHO Case Definition for People to Be Investigated for
Infection^3
* A person with an acute respiratory infection, which may include
fever (a 0/00YEN 38ADEGC, 100.4ADEGF) and cough; AND
* suspicion of pulmonary parenchymal disease (eg, pneumonia or Acute
Respiratory Distress Syndrome [ARDS]) based on clinical or
radiological evidence of consolidation; AND
* travel to or residence in an area where infection with novel
coronavirus has recently been reported or where transmission could
have occurred; AND
* not already explained by any other infection or aetiology,
including all clinically indicated tests for community-acquired
pneumonia according to local management guidelines.
Diagnostic Tests
Confirmatory testing is via nucleic acid amplification, which is
available at reference labs; standard coronavirus primers may be able
to detect the virus. Samples are to be handled in a BSL-3 setting.
Many Questions Remain
The detection of the new coronavirus raises many questions that will
likely be answered in the months to come, including:
* Are there asymptomatic cases? Will serosurveys be performed?
* Given that human-to-human transmission appears difficult for the
virus, what is the common exposure between the 2 cases? Is it
animal related?
* As with SARS, does the possibility exist of superspreaders who are
able to transmit the virus between humans?
* Are there prior unexplained cases that can be attributed to this
virus?
References
1. McIntosh K, Perlman S. Coronaviruses, including Severe Acute
Respiratory Syndrome (SARS)-associated coronavirus. In: Mandell GL,
Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's
Principles and Practice of Infectious Diseases. 7th ed.
Philadelphia, PA: Churchill Livingstone; 2010.
2. UK Health Protec
