Re: [time-nuts] Experience with THS788 from TI?
On 03/22/2012 10:17 PM, Attila Kinali wrote: On Thu, 22 Mar 2012 11:12:40 -0400 Ben Gamaribgam...@physics.umass.edu wrote: If you are really going to build your own design, then i suggest you read these papers: Thank you very much for this list. While I have already stumbled upon a few of the FPGA papers, I'm largely ignorant of the other possible approaches. Given the limitations of FPGA TDCs, it will be nice to see what is possible by other means. I'm quite sure there is much more around. I only dug a little bit a weekend or so and got a couple of intersting papers. It is also a good idea, to dig trough old circuit descriptions, form the 70s and older. You will find there many forgotten gems, that get increasingly relevant when you leave the digital domain, especially when going high speed. That being said, I'm quite keen on bringing up something on the FPGA. I just got the power supplies on the PandaDAQ running last night (QFN is a pain without my shiny new hot air rework station), so it seems that soon enough I'll have a Spartan 6 at my disposal. *g* If you do QFN or any serious SMD stuff, get a Leiter HOT JET S with fine nozzles (3mm and 5mm), or anything similar. Normal hot air guns don't really work and a complete rework station is way too expensive for anything a mere mortal does. On the other hand, with such a Hot Jet S (or similar) you can even solder BGAs, reliably. Time-Interval Measurements Based on SAW Filter Excitation, by Petr Panek, 2007 Time interval measurement device based on surface acoustic wave filter excitation, providing 1ps precision and stability, by Panek and Prochazka, 2007 Random Erros in Time Interval Measurement Based on SAW Filter Excitation, by Petr Panek, 2008 A very nice idea on how to use a high frequency startable oscillator with an ADC as phase detector. Panek claims to get below 1ps with a 200MHz clock and a 525MHz filter/oscillator. His calculations indicate that the ultimate limit of resolution is given by the sampling jitter of the ADC and the frequency and bandwidth (ie the Q of the oscillator). There Oops.. There is a sentence missing... Interrupts are bad for emails. There is even a report of a similar design, using an LC tank as resonant circuit that got into the10ps RMS region. See High frequency, high time time resolution time-to-digital converter emplying passive resonant circuits, by Ripamonti, Abba and Geracy, 2010 http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,%20high%20time%20resolution%20time-to-digital%20converter%20employing%20passive%20resonating%20circuits.pdf But getting to below that will not be easy. Mainly due to all those side effect, non-idealities and other stuff you have to deal with. And be aware, that you are dealing with an high frequncy/high speed circuit. Crudly said, you are in the ballpark of a 1/10ps = 100GHz system. Everything has to be right to get you there. Sure. This is the real issue. I am a physicist by training, so the basics of high-speed design are largely a mystery to me. From application notes (in particular Jim Williams' old but very readable work) I've gleaned the following, 1) Keep traces short and well impedence matched 2) Ample bypassing 3) Ground plane is essential 4) Know where thy return path is! I recommend getting the Tietze-Schenk Halbleiter Schaltungstechnik (resp Electronic Circuits in englisch). It's like Horowitz, just with more theoretical background and more explenation how to design stuff. Ie you get the formulas to calculate what you need if you want to go to the limit. It's still very much practical (only as much theory as needed) but covers enough of the theory if you want to have more than just cookbook examples. I'm still looking for a good high speed / high frequency book. I've asked for literature in that area a few weeks ago on this list, but have not gotten the time yet to read all those books. You might want to check the answers too. For high speed digital design this is a good starter: http://www.amazon.com/High-Speed-Digital-Design-Handbook/dp/0133957241/ref=sr_1_1?ie=UTF8qid=1332491581sr=8-1 It's a very good read and accelerated my knowledge quickly in one blow many years ago. It's not heavy on the math department, but teaches what the effects are and gives lot of thumb-rules which is easy to remember. It was then followed by: http://www.amazon.com/High-Speed-Signal-Propagation-Advanced/dp/013084408X/ref=pd_bxgy_b_text_b Which goes deeper. While the focus is digital designs, much of the physics is the same for RF. Few of the RF books I've seen has come close to the practically oriented teaching of these books. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Experience with THS788 from TI?
On Fri, 23 Mar 2012 09:37:58 +0100 Magnus Danielson mag...@rubidium.dyndns.org wrote: For high speed digital design this is a good starter: http://www.amazon.com/High-Speed-Digital-Design-Handbook/dp/0133957241/ref=sr_1_1?ie=UTF8qid=1332491581sr=8-1 It's a very good read and accelerated my knowledge quickly in one blow many years ago. It's not heavy on the math department, but teaches what the effects are and gives lot of thumb-rules which is easy to remember. It was then followed by: http://www.amazon.com/High-Speed-Signal-Propagation-Advanced/dp/013084408X/ref=pd_bxgy_b_text_b Thanks for the hint. I'll have a look at those! Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LORAN C 89700 dropped carriers at 1615 EST after a solid 3 days
Hi Paul and others, Please give your QTH when posting. Any ids would be appreciated. I have been talking with one of the ETs at the Wildwood NJ site. Film at 11. 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Thursday, March 22, 2012 4:49 PM To: Time-nuts; paul swed Subject: [time-nuts] LORAN C 89700 dropped carriers at 1615 EST after a solid 3 days Best run yet, 3 solid days of operation and I was able to log various local references as compared to a HP3801 and Tbolt. Only 2 stations generally on the air. 89700 Master and X, but an unidentified one came up for a short bit in the 4th position Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Experience with THS788 from TI?
mag...@rubidium.dyndns.org said: For high speed digital design this is a good starter: http://www.amazon.com/ High-Speed-Digital-Design-Handbook/dp/0133957241/ref=sr_1_1?ie=UTF8qid=13324 91581sr=8-1 You forgot the sub-title: High Speed Digital Design: A Handbook of Black Magic I really like it. It's mostly old style, TTL, low tech, or common sense. Mostly that means not much math. But it lists at $84. There is another pair of books that I really like: Lee Richey Right the First Time http://www.speedingedge.com/rtft_book.htm At $170 for the pair, they are expensive for the hobbyist but well worth it (my opinion) if you are designing commercial boards. There is a whole branch of this area called Signal Integrity with a mailing list at: SI-LIST http://www.freelists.org/archive/si-list Beware, lots of noise (again, my opinion). I hate the top-posting culture but there are enough occasional gems that I'm still subscribed. (Someday, I'm going to compute the signal-noise ratio on that list. :) -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LORAN C 89700 dropped carriers at 1615 EST after a solid 3 days
I am in Boston Interesting that some still hear the transmission. Still quite this morning near boston. On Fri, Mar 23, 2012 at 7:10 AM, Bill Riches bill.ric...@verizon.netwrote: Hi Paul and others, Please give your QTH when posting. Any ids would be appreciated. I have been talking with one of the ETs at the Wildwood NJ site. Film at 11. 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Thursday, March 22, 2012 4:49 PM To: Time-nuts; paul swed Subject: [time-nuts] LORAN C 89700 dropped carriers at 1615 EST after a solid 3 days Best run yet, 3 solid days of operation and I was able to log various local references as compared to a HP3801 and Tbolt. Only 2 stations generally on the air. 89700 Master and X, but an unidentified one came up for a short bit in the 4th position Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble T'Bolt
Probably older. Date Code is 9932. However, I wonder if you could 'transplant' a newer TBolt into the case and use the built in 24 VDC power supply? Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stan, W1LE Sent: Friday, March 23, 2012 8:34 AM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Trimble T'Bolt Hello The Net, On Ebay: 120880795618 Is this a very old T'Bolt or the newer e T'Bolt ? I like the single power supply even though it is 24VDC Stan, W1LECape Cod ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble T'Bolt
It's the original Thunderbolt. It's the same as the gold-cased OEM units available on the bay, but it includes an internal dc-dc converter that provides the 3 voltages for the gps board. 73, geo - n4ua On Fri, Mar 23, 2012 at 9:33 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, On Ebay: 120880795618 Is this a very old T'Bolt or the newer e T'Bolt ? I like the single power supply even though it is 24VDC Stan, W1LECape Cod __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble T'Bolt
Hi Stan With a 99 date code that's looking pretty old and will more than likely have the earlier Piezo oscillator as per John's comments here _http://www.ke5fx.com/tbolt.htm_ (http://www.ke5fx.com/tbolt.htm) It's certainly not one I'd go for. Regards Nigel GM8PZR In a message dated 23/03/2012 13:34:42 GMT Standard Time, stanw...@verizon.net writes: Hello The Net, On Ebay: 120880795618 Is this a very old T'Bolt or the newer e T'Bolt ? I like the single power supply even though it is 24VDC Stan, W1LECape Cod ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble T'Bolt
Yes, you can, but you need to transplant the in-line power header in the old board to the new board and mount it on the back side of the pwb. 73, geo - n4ua On Fri, Mar 23, 2012 at 9:46 AM, J. L. Trantham jlt...@att.net wrote: Probably older. Date Code is 9932. However, I wonder if you could 'transplant' a newer TBolt into the case and use the built in 24 VDC power supply? Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stan, W1LE Sent: Friday, March 23, 2012 8:34 AM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Trimble T'Bolt Hello The Net, On Ebay: 120880795618 Is this a very old T'Bolt or the newer e T'Bolt ? I like the single power supply even though it is 24VDC Stan, W1LECape Cod ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Anyone familiar with SR-620 repair?
My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? Thanks, John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Experience with THS788 from TI?
On 03/23/2012 12:36 PM, Hal Murray wrote: mag...@rubidium.dyndns.org said: For high speed digital design this is a good starter: http://www.amazon.com/ High-Speed-Digital-Design-Handbook/dp/0133957241/ref=sr_1_1?ie=UTF8qid=13324 91581sr=8-1 You forgot the sub-title: High Speed Digital Design: A Handbook of Black Magic Oh yes, like the title... too. :) I really like it. It's mostly old style, TTL, low tech, or common sense. Mostly that means not much math. But it lists at $84. And ECL. It's not the leading edge math, but as a crash-coarse I think few if any books is as good at getting the message across. Thanks for those other tips. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Not w/ that instrument, but try the following. I assume you have the book w/ schematics. Power the unit and with a DMM or VOM check the PS rails to see which is sick. From the book, locate all bypass caps on that rail. Put your DMM across each in turn. The one with the lowest drop is likely the culprit. If there is more than one w/ low voltage, it's likely the one closest to the power supply. You might try touching all the bypass caps to see if any are runni9ng hot. This does not always work, because zero voltage or zero current dissipates nothing. -John == My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? Thanks, John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Great advice. I have the manual, but it doesn't include schematics. I think someone on the list has a PDF of the schematics, so I'll be digging around for that before I start digging into the box. John On 3/23/2012 2:36 PM, J. Forster wrote: Not w/ that instrument, but try the following. I assume you have the book w/ schematics. Power the unit and with a DMM or VOM check the PS rails to see which is sick. From the book, locate all bypass caps on that rail. Put your DMM across each in turn. The one with the lowest drop is likely the culprit. If there is more than one w/ low voltage, it's likely the one closest to the power supply. You might try touching all the bypass caps to see if any are runni9ng hot. This does not always work, because zero voltage or zero current dissipates nothing. -John == My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? Thanks, John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Very nice to see schematics. I do not have a sr620. Looks good. You have been given some great guidance on seeing what supply is loaded. Thats the first step. Then I look for those nasty tear drop tants. Sometimes there is a clue they are baking or as I think John said feel them when they have been on a bit. Its possible that one of the chips has an issue try feeling those also. I see a lot of ecl so that can get nasty to troubleshoot. Regards Paul. WB8TSL On Fri, Mar 23, 2012 at 3:04 PM, Marek Peca ma...@duch.cz wrote: Great advice. I have the manual, but it doesn't include schematics. I think someone on the list has a PDF of the schematics, so I'll be digging around for that before I start digging into the box. SR620 schematics: http://rtime.felk.cvut.cz/~**pecam1/SR620_sch.pdfhttp://rtime.felk.cvut.cz/~pecam1/SR620_sch.pdf Good luck please report your results, Marek __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
On 03/23/2012 07:32 PM, John Ackermann N8UR wrote: My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? You have several tantal caps in there. They can have short-circuit as failure mode. Use the schematic and PDF manual to follow up. Make a note of which stabs/transistors over-heat and then turn off and try to see if any of the caps is also hot. The design has no fold-back on over-current of the power lines. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
I should have added that you can get a pretty good idea of whick branch on a PCB is drawing current by probing along the trace. This is especially useful if the rail has a bunch of branch distribution lines. Also, if the three-terminal regulator is overheating, disconnect it and power just that rail from an external, current limited supply of a volt or two. That way you don't risk trace damage. Best, -John My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? Thanks, John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
On 03/23/2012 09:30 PM, J. Forster wrote: I should have added that you can get a pretty good idea of whick branch on a PCB is drawing current by probing along the trace. This is especially useful if the rail has a bunch of branch distribution lines. Also, if the three-terminal regulator is overheating, disconnect it and power just that rail from an external, current limited supply of a volt or two. That way you don't risk trace damage. I would toss the TDR on it just for the fun of it, but a miliohm measurement should also help to locate it. Otherwise if there is no direct evidence (hot cap or other chip) lifting legs of caps on speculation can be a starter. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Shame you do not have a Hall effect probe to drag down the trace. John WA4WDL -- From: Magnus Danielson mag...@rubidium.dyndns.org Sent: Friday, March 23, 2012 4:58 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Anyone familiar with SR-620 repair? On 03/23/2012 09:30 PM, J. Forster wrote: I should have added that you can get a pretty good idea of whick branch on a PCB is drawing current by probing along the trace. This is especially useful if the rail has a bunch of branch distribution lines. Also, if the three-terminal regulator is overheating, disconnect it and power just that rail from an external, current limited supply of a volt or two. That way you don't risk trace damage. I would toss the TDR on it just for the fun of it, but a miliohm measurement should also help to locate it. Otherwise if there is no direct evidence (hot cap or other chip) lifting legs of caps on speculation can be a starter. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Hi Magnus, I very much doubt you could get anything useful out of a TDR. There is no reason I can think of that a power rail should look anything like a transmission line and the rail should be an AC short every inch or so. FWIW, -John On 03/23/2012 09:30 PM, J. Forster wrote: I should have added that you can get a pretty good idea of whick branch on a PCB is drawing current by probing along the trace. This is especially useful if the rail has a bunch of branch distribution lines. Also, if the three-terminal regulator is overheating, disconnect it and power just that rail from an external, current limited supply of a volt or two. That way you don't risk trace damage. I would toss the TDR on it just for the fun of it, but a miliohm measurement should also help to locate it. Otherwise if there is no direct evidence (hot cap or other chip) lifting legs of caps on speculation can be a starter. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Are there Hall Effect probes for chasing DC faults? I'm very familiar with the HP Logic Current Tracer, but AFAIK that is only sensitive to fast pulses, from the Logic Pulser for example. The threashold is adjustable, so maybe it will sense DC currents. If it is DC sensitive it'd be even more wonderful. I'll try it after dinner. Thanks, -John Shame you do not have a Hall effect probe to drag down the trace. John WA4WDL -- From: Magnus Danielson mag...@rubidium.dyndns.org Sent: Friday, March 23, 2012 4:58 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Anyone familiar with SR-620 repair? On 03/23/2012 09:30 PM, J. Forster wrote: I should have added that you can get a pretty good idea of whick branch on a PCB is drawing current by probing along the trace. This is especially useful if the rail has a bunch of branch distribution lines. Also, if the three-terminal regulator is overheating, disconnect it and power just that rail from an external, current limited supply of a volt or two. That way you don't risk trace damage. I would toss the TDR on it just for the fun of it, but a miliohm measurement should also help to locate it. Otherwise if there is no direct evidence (hot cap or other chip) lifting legs of caps on speculation can be a starter. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
HP once made a kit with DIP logic clip, logic probe, logic pulser, and current tracer. Pulser and tracer made finding shorts pretty easy. For the SR-620 you could disconnect the regulator and inject current pulses there, follow them around with current tracer. The same basic trick works given a bench type pulse generator as the injector, following the current with a chopped down magnetic tape head feeding a scope (or spec analyzer?). Been there, done that. Made my own RF type probe with just a small coil at the tip. Have the HP logic kit as well. Bob LaJeunesse ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] CW12-TIM
Hi Group; Has anyone played with the CW12-TIM? I am hoping it is a plug and play replacement for the M12+ in my Commsync II with better performance. Is there any other product I should look at? Thanks; Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Here is a trick or two that may work: feed a very small AC voltage with say 1KHz and 10mV into the bad power rail. It won't hurt anything. Then use an old cassette players' magnetic pickup and amplifier to follow the signal to the short. No need for expensive hall effect meters. Another trick that I often use is force-feed power into the bad power rail. If it's a 5V rail, then say 5V at 2A. That can work by having the bad part get hot really quickly, by allowing you to DC probe with a millivolt setting, or it can backfire if it's a tant cap by blowing it up. I would use that only as a last resort if the first trick didn't work, as the second trick can be dangerous! So please be careful, any repair should be done only with proper equipment (using a 110V isolation transformer for example)... bye, Said In a message dated 3/23/2012 14:13:57 Pacific Daylight Time, j...@quikus.com writes: Are there Hall Effect probes for chasing DC faults? I'm very familiar with the HP Logic Current Tracer, but AFAIK that is only sensitive to fast pulses, from the Logic Pulser for example. The threashold is adjustable, so maybe it will sense DC currents. If it is DC sensitive it'd be even more wonderful. I'll try it after dinner. Thanks, -John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
One technique that works for me is to remove the bolts holding the regulator tabs against the heat sink, and ensure that the tabs are not touching same. Then, starting with the unit at ambient temperature, apply power for ten seconds or so, and then use an IR temperature sensor to determine which regulator is getting hot. Lacking an IR tool, a fingertip will suffice. This technique will quickly identify which part of the circuitry is drawing excessive power. Needless to say, the power-on time must be short to avoid damaging the regulators while operating without a heat sink. 73, Eric Lemmon WB6FLY ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] UK ANN: NOTIFICATION OF GPS JAMMING EXERCISES SALISBURY PLAIN, WILTSHIRE, 7TH MAY 2012
NOTIFICATION OF GPS JAMMING EXERCISES SALISBURY PLAIN, WILTSHIRE, 7TH MAY 2012 Dates: Between the 7th of May and the 11th of May 2012 (Inclusive). Times: : 0700 - 2000 GMT. Location of MULTIPLE jammers: Land based within 5km of N51° 12', W001° 58.5'. Frequency: A 24 MHz band centred around 1575.42MHz (GPS L1) Total Power: Up to 10 Watts EIRP. It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Here is a trick or two that may work: feed a very small AC voltage with say 1KHz and 10mV into the bad power rail. It won't hurt anything. Then use an old cassette players' magnetic pickup and amplifier to follow the signal to the short. No need for expensive hall effect meters. Good bypass caps are near AC shorts. I've not tried it, but am not optomistic. It would work on stuck signals lines, but not well on power, IMO. Another trick that I often use is force-feed power into the bad power rail. If it's a 5V rail, then say 5V at 2A. That can work by having the bad part get hot really quickly, by allowing you to DC probe with a millivolt setting, or it can backfire if it's a tant cap by blowing it up. I would use that only as a last resort if the first trick didn't work, as the second trick can be dangerous! Be aware, you can overheat and burn out PCB traces or vias. Small capacitors don't make a real mess when they poip, but I would most certainly wear glasses. -John == So please be careful, any repair should be done only with proper equipment (using a 110V isolation transformer for example)... bye, Said In a message dated 3/23/2012 14:13:57 Pacific Daylight Time, j...@quikus.com writes: Are there Hall Effect probes for chasing DC faults? I'm very familiar with the HP Logic Current Tracer, but AFAIK that is only sensitive to fast pulses, from the Logic Pulser for example. The threashold is adjustable, so maybe it will sense DC currents. If it is DC sensitive it'd be even more wonderful. I'll try it after dinner. Thanks, -John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
The HP 547A Current Tracer is an AC only instrument, as I thought. It uses a coil as a pickup, not a Hall device. See: http://cp.literature.agilent.com/litweb/pdf/00547-90006.pdf Page 11 Too bad. :(( -John == In a message dated 3/23/2012 14:13:57 Pacific Daylight Time, j...@quikus.com writes: Are there Hall Effect probes for chasing DC faults? I'm very familiar with the HP Logic Current Tracer, but AFAIK that is only sensitive to fast pulses, from the Logic Pulser for example. The threashold is adjustable, so maybe it will sense DC currents. If it is DC sensitive it'd be even more wonderful. I'll try it after dinner. Thanks, -John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Shouldn't be too bad, a 10uF cap would have 15 Ohms impedance at 1KHz, 150 Ohms at 100Hz, and one could inject at different places on the trace... away from the big bypass caps. Doing the same with DC and a simple multimeter should work too. bye, Said In a message dated 3/23/2012 14:31:42 Pacific Daylight Time, j...@quikus.com writes: Here is a trick or two that may work: feed a very small AC voltage with say 1KHz and 10mV into the bad power rail. It won't hurt anything. Then use an old cassette players' magnetic pickup and amplifier to follow the signal to the short. No need for expensive hall effect meters. Good bypass caps are near AC shorts. I've not tried it, but am not optomistic. It would work on stuck signals lines, but not well on power, IMO. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Most instrument PCBs have scores of bypass caps... all in parallel. -John = Shouldn't be too bad, a 10uF cap would have 15 Ohms impedance at 1KHz, 150 Ohms at 100Hz, and one could inject at different places on the trace... away from the big bypass caps. Doing the same with DC and a simple multimeter should work too. bye, Said In a message dated 3/23/2012 14:31:42 Pacific Daylight Time, j...@quikus.com writes: Here is a trick or two that may work: feed a very small AC voltage with say 1KHz and 10mV into the bad power rail. It won't hurt anything. Then use an old cassette players' magnetic pickup and amplifier to follow the signal to the short. No need for expensive hall effect meters. Good bypass caps are near AC shorts. I've not tried it, but am not optomistic. It would work on stuck signals lines, but not well on power, IMO. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Anyone familiar with SR-620 repair?
On our side of the pond there is/was a device called the Polar Toneohm. It used a hall effect device to translate the current flowing in a track to a tone - rising pitch, higher current. These could be very effective in finding shorts in power rails etc, also in multi-layer boards. Google Toneohm and you will see. Geoff -- # Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UK ge...@palaemon.co.uk or melecert...@gmail.com Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparc and even on the NAS. Avoiding Micro$oft like the plague. # ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CW12-TIM
Yes, the CW12-TIM was designed as a drop-in replacement for the M12+. Search the archives and you'll find out more about it. One thing to note is that the CW12-TIM doesn't support sawtooth correction so the 1 PPS may or may not be an improvement over the M12+. Ed On 3/23/2012 3:16 PM, Tom Knox wrote: Hi Group; Has anyone played with the CW12-TIM? I am hoping it is a plug and play replacement for the M12+ in my Commsync II with better performance. Is there any other product I should look at? Thanks; Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
In my opinion, if you are hunting for a short, there is a little to do with the current: it is always the same, better use a voltmeter/millivoltmeter and hunt for the least voltage across capacitors or the greatest voltage drop on traces... On Fri, Mar 23, 2012 at 11:36 PM, Geoff Blake melecert...@gmail.com wrote: On our side of the pond there is/was a device called the Polar Toneohm. It used a hall effect device to translate the current flowing in a track to a tone - rising pitch, higher current. These could be very effective in finding shorts in power rails etc, also in multi-layer boards. Google Toneohm and you will see. Geoff -- # Geoff Blake, G8GNZJO01fq: Chelmsford, Essex, UK ge...@palaemon.co.ukor melecert...@gmail.com Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparc and even on the NAS. Avoiding Micro$oft like the plague. # ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
SRS620 schematics are on ko4bb.com Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: John Ackermann N8UR j...@febo.com Sender: time-nuts-boun...@febo.com Date: Fri, 23 Mar 2012 14:46:07 To: j...@quikus.com; Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Anyone familiar with SR-620 repair? Great advice. I have the manual, but it doesn't include schematics. I think someone on the list has a PDF of the schematics, so I'll be digging around for that before I start digging into the box. John On 3/23/2012 2:36 PM, J. Forster wrote: Not w/ that instrument, but try the following. I assume you have the book w/ schematics. Power the unit and with a DMM or VOM check the PS rails to see which is sick. From the book, locate all bypass caps on that rail. Put your DMM across each in turn. The one with the lowest drop is likely the culprit. If there is more than one w/ low voltage, it's likely the one closest to the power supply. You might try touching all the bypass caps to see if any are runni9ng hot. This does not always work, because zero voltage or zero current dissipates nothing. -John == My SRS SR-620 counter died last weekend. After superficial troubleshooting, it looks like there's probably a short on one of the power supply rails. Symptom is that nothing lights up when power is turned on, but one or more of the three terminal regulators gets very, very hot (can't tell which one since they're all bolted to the side rail as heat sink). The unit had been running continuously for several weeks when the failure occurred. I just learned from SRS that they charge a flat rate 25% of the current list price for repairs! (To be fair, if you're the original purchaser, it's only 20%.) The SR620 currently lists for about $5K, so we're talking about a mighty expensive shorted cap (if that's what it is)! Anyway, has anyone here troubleshot an SR-620 with a problem like this, or have any general insights about working on one of these beasts? Thanks, John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CW12-TIM
Thanks Ed, My Commsync has the LPN clean up oscillator option do you think that will clean up the sawtooth? Thomas Knox Date: Fri, 23 Mar 2012 16:56:50 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM Yes, the CW12-TIM was designed as a drop-in replacement for the M12+. Search the archives and you'll find out more about it. One thing to note is that the CW12-TIM doesn't support sawtooth correction so the 1 PPS may or may not be an improvement over the M12+. Ed On 3/23/2012 3:16 PM, Tom Knox wrote: Hi Group; Has anyone played with the CW12-TIM? I am hoping it is a plug and play replacement for the M12+ in my Commsync II with better performance. Is there any other product I should look at? Thanks; Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CW12-TIM
act...@hotmail.com said: Thanks Ed, My Commsync has the LPN clean up oscillator option do you think that will clean up the sawtooth? I doubt it. What's the time constant on the PLL? Do you know about hanging bridges? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP117A manual
It's on the Agilent site. Not a great copy, but readable. www.agilent.com -John === Just located an antique HP117A in the basement. Can someone direct me to a free source for the manual? I collect boatanchors and this is sort of one. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP117A manual
Try KO4bbs website Pretty sure thats how I picked my manual up. Can forward if need be. Further I have 2 working so if I can help let me know. They had definitely lived in a basement for way to many years. But they sure don't look or act like that now. Regards Paul WB8TSL On Fri, Mar 23, 2012 at 8:21 PM, Bill Fuqua wlfuq...@uky.edu wrote: Just located an antique HP117A in the basement. Can someone direct me to a free source for the manual? I collect boatanchors and this is sort of one. 73 Bill wa4lav __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP117A manual
Believe it or not you can get it from Agilent http://www.home.agilent.com/agilent/techSupport.jspx?pid=117A%3Aepsg%3ApropageMode=PLt=79841.g.1cc=USlc=eng if the above does not work just put 117A in their search its a pretty crappy scan but usable -pete has two of them On Fri, Mar 23, 2012 at 5:21 PM, Bill Fuqua wlfuq...@uky.edu wrote: Just located an antique HP117A in the basement. Can someone direct me to a free source for the manual? I collect boatanchors and this is sort of one. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB BPSK Receiver Project?
OK, John Forster and I have been kicking around a few things off line, and he suggested I should bring part of it back on line. Maybe I have a few details wrong, or maybe I have them right and some folks are unaware of them. My concern about the BPSK, and breaking my Spectracom oscillator, is really centered on loosing my NIST traceable reference oscillator. I don't care one bit what time of day it is. I wrote: I did poke around a bit, and it appears that WWVB is still an approved frequency standard, so any oscillator which is phased locked to WWVB qualifies as an NIST traceable standard reference oscillator, which is my only concern. John wrote: Good news! Thanks. I wrote: A GPS disciplined oscillator, regardless of how stable/accurate it may be, is not an NIST traceable standard unless NIST decides to certify the Naval Observatory as a standard. Or I suppose NIST could take over the GPS correction uploads.but I don't see that happening any time soon. That's really outside their mission boundary. Maybe a few things have changed in the metrology world in past few years, but the GPS based oscillators are controlled by the Naval Observatory clocks, not the NIST clocks. So while an HP-117 or a Spectracon 8160 oscillator phase locked to WWVB is by definition an NIST traceable standard so long as it is in lock and you have a valid lock history, a GPS unit, even though it may be just as stable an oscillator, isn't an NIST traceable standard without a whole lot of equipment to validate that NIST and the GPS system are in sync. (There is/was actually a commercial solution to verify this, but it isn't/wasn't cheap.) For all you metrology guys out there, has any of this recently changed? So my interest in keep my Spectracom going isn't just to keep a stable 10 MHz oscillator in the lab. The GPS will give me a stable signal. My interest is in keeping a stable and traceable 10 MHz signal going. After all, all our old gray-hair tax dollars paid for this government service over the past 5 decades. Why should we get kicked off the bus now? It isn't like we want anything new. Just don't break what we've already paid for. Michael ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CW12-TIM
Sorry Thomas. I don't know a thing about the Commsync II. See what you can dig out of the manuals. Ultimately, you might have to bite the bullet and buy a CW12 to try it. Sometimes that's the only way to find out. Ed On 3/23/2012 6:10 PM, Tom Knox wrote: Thanks Ed, My Commsync has the LPN clean up oscillator option do you think that will clean up the sawtooth? Thomas Knox Date: Fri, 23 Mar 2012 16:56:50 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM Yes, the CW12-TIM was designed as a drop-in replacement for the M12+. Search the archives and you'll find out more about it. One thing to note is that the CW12-TIM doesn't support sawtooth correction so the 1 PPS may or may not be an improvement over the M12+. Ed On 3/23/2012 3:16 PM, Tom Knox wrote: Hi Group; Has anyone played with the CW12-TIM? I am hoping it is a plug and play replacement for the M12+ in my Commsync II with better performance. Is there any other product I should look at? Thanks; Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CW12-TIM
I have already bite the bullet, After reading the manual I thought it was worth a try. It should arrive Tuesday. So next week I will post what I find. Thanks; Thomas Knox Date: Fri, 23 Mar 2012 19:17:06 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM Sorry Thomas. I don't know a thing about the Commsync II. See what you can dig out of the manuals. Ultimately, you might have to bite the bullet and buy a CW12 to try it. Sometimes that's the only way to find out. Ed On 3/23/2012 6:10 PM, Tom Knox wrote: Thanks Ed, My Commsync has the LPN clean up oscillator option do you think that will clean up the sawtooth? Thomas Knox Date: Fri, 23 Mar 2012 16:56:50 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM Yes, the CW12-TIM was designed as a drop-in replacement for the M12+. Search the archives and you'll find out more about it. One thing to note is that the CW12-TIM doesn't support sawtooth correction so the 1 PPS may or may not be an improvement over the M12+. Ed On 3/23/2012 3:16 PM, Tom Knox wrote: Hi Group; Has anyone played with the CW12-TIM? I am hoping it is a plug and play replacement for the M12+ in my Commsync II with better performance. Is there any other product I should look at? Thanks; Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Anyone familiar with SR-620 repair?
You don't need expensive test equipment to find this kind of problem. What I use is a sheet of liquid crystal film with a transition temperature just slightly above your room temperature. Just lay it on the circuit board and you can find where the power is being dissipated (even if pretty small) by watching the colors change. I think Omega Engineering sells a 8.5 x 11 sheet for about $18 if memory serves me. I have used this trick many times and it works great to find shorted (bypass) caps. No disconnecting anything, no milliohm meters, no 4 or 5 digit voltmeters. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
Prior to emission or IR microscope technology, liquid crystals was how you found hotspots on ICs. I've done this with a goop that you dispense with a syringe. One trick to make this more sensitive is you bring a soldering iron close to the liquid crystals. Not so close as to cause a change, but you get them closer to the phase change point. -Original Message- From: Skip Withrow skip.with...@gmail.com Sender: time-nuts-boun...@febo.com Date: Fri, 23 Mar 2012 21:07:45 To: time-nuts@febo.com Reply-To: swith...@alum.mit.edu, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Anyone familiar with SR-620 repair? You don't need expensive test equipment to find this kind of problem. What I use is a sheet of liquid crystal film with a transition temperature just slightly above your room temperature. Just lay it on the circuit board and you can find where the power is being dissipated (even if pretty small) by watching the colors change. I think Omega Engineering sells a 8.5 x 11 sheet for about $18 if memory serves me. I have used this trick many times and it works great to find shorted (bypass) caps. No disconnecting anything, no milliohm meters, no 4 or 5 digit voltmeters. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
I had a HP 3326 which had a power supply in foldback. All the modules are inaccessible unless you have a rather rare set of extenders anyway. The voltmeter method quickly led me to the board and a bench supply and meter again to the shorted cap. Very easy. Other times I've borrowed the FLIR camera from work, also taught the new EEs that trick as well. It is a true lifesaver on dense surface mount boards. I haven't tried the liquid crystal sheet but it seems like an interesting idea so long as everything is about the same height. Peter On Mar 23, 2012, at 11:53 PM, li...@lazygranch.com wrote: Prior to emission or IR microscope technology, liquid crystals was how you found hotspots on ICs. I've done this with a goop that you dispense with a syringe. One trick to make this more sensitive is you bring a soldering iron close to the liquid crystals. Not so close as to cause a change, but you get them closer to the phase change point. -Original Message- From: Skip Withrow skip.with...@gmail.com Sender: time-nuts-boun...@febo.com Date: Fri, 23 Mar 2012 21:07:45 To: time-nuts@febo.com Reply-To: swith...@alum.mit.edu, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Anyone familiar with SR-620 repair? You don't need expensive test equipment to find this kind of problem. What I use is a sheet of liquid crystal film with a transition temperature just slightly above your room temperature. Just lay it on the circuit board and you can find where the power is being dissipated (even if pretty small) by watching the colors change. I think Omega Engineering sells a 8.5 x 11 sheet for about $18 if memory serves me. I have used this trick many times and it works great to find shorted (bypass) caps. No disconnecting anything, no milliohm meters, no 4 or 5 digit voltmeters. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Anyone familiar with SR-620 repair?
I just tracked down a shorted tantalum in a Tektronix DM501 multimeter. It was on the output of the floating -12 volt supply bridge rectifier before the regulator. The current level was so low that it never heated up although I burned two fingers on the push-pull output transistors for the floating supply. The regulator is on a separate module but the supply was still shorted when I pulled it and the bad tantalum was the only part left. I have not seen a shorted tantalum before where it could not be surge current related until now. On Sat, 24 Mar 2012 00:08:12 -0400, Peter Gottlieb n...@verizon.net wrote: I had a HP 3326 which had a power supply in foldback. All the modules are inaccessible unless you have a rather rare set of extenders anyway. The voltmeter method quickly led me to the board and a bench supply and meter again to the shorted cap. Very easy. Other times I've borrowed the FLIR camera from work, also taught the new EEs that trick as well. It is a true lifesaver on dense surface mount boards. I haven't tried the liquid crystal sheet but it seems like an interesting idea so long as everything is about the same height. Peter On Mar 23, 2012, at 11:53 PM, li...@lazygranch.com wrote: Prior to emission or IR microscope technology, liquid crystals was how you found hotspots on ICs. I've done this with a goop that you dispense with a syringe. One trick to make this more sensitive is you bring a soldering iron close to the liquid crystals. Not so close as to cause a change, but you get them closer to the phase change point. -Original Message- From: Skip Withrow skip.with...@gmail.com Sender: time-nuts-boun...@febo.com Date: Fri, 23 Mar 2012 21:07:45 To: time-nuts@febo.com Reply-To: swith...@alum.mit.edu, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Anyone familiar with SR-620 repair? You don't need expensive test equipment to find this kind of problem. What I use is a sheet of liquid crystal film with a transition temperature just slightly above your room temperature. Just lay it on the circuit board and you can find where the power is being dissipated (even if pretty small) by watching the colors change. I think Omega Engineering sells a 8.5 x 11 sheet for about $18 if memory serves me. I have used this trick many times and it works great to find shorted (bypass) caps. No disconnecting anything, no milliohm meters, no 4 or 5 digit voltmeters. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] ANN UK: MSF 60KHz interruption - Mon Mar 26 - Fri Apr 06
Folks, I have received notice that the MSF 60 KHz signal from Anthorn, Cumbria, UK will be off-air 08:00 UTC Mon 2012-Mar-26 to 20:00 2012-Apr-06. The service may be off-air continuously during the period, but will be restored overnight and at the weekend whenever possible. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
