Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter
On Mon, Jan 25, 2016 at 04:52:56PM +, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > It is the same general type, but the pinout is wrong. Mine has two radial > pins, not 3. That will not fit. Sorry, I understand now it's a 2/3A, much bigger. The original LX1634 (LX16/34) is a Li-SO2, 850mAh, 2.8V nominal, 3V open circuit. Current SAFT model is "G 32/3". Here is the datasheet http://www.saftbatteries.com/force_download/G_323.pdf I saw the code "G 32/3.4" should point to the version with PCB pins, but I wasn't able to find the original datasheet and any EU source. If you can accept to change the chemistry to a Li-MnO2, you can use the Varta 06237501301 from the supplier I suggested. This is a 2/3AA, same height, thinner, with radial leads like a capacitor, so you should find the way to fit it. Another idea could be use a holder and put a (very easy to find everywhere) CR123A. Best regards, Andrea Baldoni ___ 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] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter
On 25 January 2016 at 15:23, Andrea Baldoni wrote: > On Sun, Jan 24, 2016 at 07:54:34PM +, Dr. David Kirkby (Kirkby > Microwave Ltd) wrote: > > > I've got a HP 3457A 6.5 digit multimeter - S/N 2703A04579. It's working > > fine, but I'm aware the battery must be at least 11 years old, as I first > > bought the meter 11 years ago. I suspect its due for a change. I'm > trying > > to find a *reputable* source for a replacement. I want to avoid eBay, due > > to the number of fakes on there. > > Hello David. > If the Panasonic replacement is good, you can buy the equivalent Varta > 06127201301 from RS (their code is 240-9437). > > http://uk.rs-online.com/web/ > > Best regards, > Andrea Baldoni > It is the same general type, but the pinout is wrong. Mine has two radial pins, not 3. That will not fit. Dave ___ 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] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?
In message , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: >I've not looked myself, but I did see a note on the web there was no >documented command to do read out the cal data on a 3457A. Apart from the HP8568 I have not seen them documented on any instrument. But a good first shot: Try sending the command "MREAD 0" and see what happens... And it's not like disassembling the firmware of instruments of this vintage is a big deal anyway... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?
On 25 January 2016 at 15:40, Poul-Henning Kamp wrote: > > In message < > canx10halwjxt+8ev8lywdqy9eez+anawihgqeyrzntsy80v...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >I'm wondering if I would be better purposely removing the battery, and > >putting a short across the SRAM so I ensure the contents are definitely > >lost. My logic is that > > I would save the content before doing that, so that I could compare it > to whatever I got back from calibration. > > My experience so far says that there probably is a GPIB command which > can read out the memory, but of course you still need to know the > address-space layout. > I've not looked myself, but I did see a note on the web there was no documented command to do read out the cal data on a 3457A. But in any case, unless I know how to interpret those values, a bunch of meaningless 0's and 1's is not going to be a lot of use. Of course, if I could save them I would, then in the event someone ever figures out what the numbers mean, I could do a comparison. It would be nice to know if the meter is in/out of spec, but to me, I think having it put as close as possible to correct is more worthwhile, even though a metrologist who gets their meter calibrated regularly would no doubt see it different. Dave ___ 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] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?
In message , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: >I'm wondering if I would be better purposely removing the battery, and >putting a short across the SRAM so I ensure the contents are definitely >lost. My logic is that I would save the content before doing that, so that I could compare it to whatever I got back from calibration. My experience so far says that there probably is a GPIB command which can read out the memory, but of course you still need to know the address-space layout. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Fall of SRAM voltage in a 3457A without external power
On Mon, Jan 25, 2016 at 11:46:19AM +, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > V). and well above the 2.0 V needed to hold the SRAM contents. Assuming the > SRAM takes a constant current one would expect the voltage to fall linearly > with time. If so, it would take 46 minutes to fall to 2.0 V even without > battery power. Hello David. I think you can probably assume the SRAM idle current be proportional to e(k*v) (an experimental k for some microcontrollers with SRAM I used was 0.44), so it should decay even more slowly. Best regards, Andrea Baldoni ___ 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] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter
On Sun, Jan 24, 2016 at 07:54:34PM +, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > I've got a HP 3457A 6.5 digit multimeter - S/N 2703A04579. It's working > fine, but I'm aware the battery must be at least 11 years old, as I first > bought the meter 11 years ago. I suspect its due for a change. I'm trying > to find a *reputable* source for a replacement. I want to avoid eBay, due > to the number of fakes on there. Hello David. If the Panasonic replacement is good, you can buy the equivalent Varta 06127201301 from RS (their code is 240-9437). http://uk.rs-online.com/web/ Best regards, Andrea Baldoni ___ 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] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?
As noted in another thread, I want to replace a battery in a 3457A that has not been replaced in at least 11 years. The instrument has not been calibrated in that time either. At the time it was purchased from a dealer, I was told it was within specification, but if I wanted it calibrated I would need to pay. I never did have it calibrated, so have no historical data about this. I've no idea when it was calibrated, and have no cal certificate, so have no idea of the errors at the time of calibration. I now want to change the battery, *and* send it to Keysight for calibration - I have a healthy skepticism of 3rd party labs, so would rather pay more and get the job done by Keysight. I'm wondering if I would be better purposely removing the battery, and putting a short across the SRAM so I ensure the contents are definitely lost. My logic is that 1) If I send it to Keysight and the cal data is corrupt, they will set the meter correct. 2) If sent to Keysight, with the cal data in tact, then if its within specification they will not adjust it. So if the limit on some parameter is 1%, and the error is 0.5%, then it will not be adjusted. But if the SRAM is corrupted, the error will be huge (if it will read at all), so it would force Keysight to adjust it to the correct value. At that point the error should be effectively zero given its a 6.5 digit multimeter, which means the uncertainly in Keysight's measurements should be much lower than the uncertainty of my meter. So by corrupting the SRAM, I should get a meter returned to me that is more accurately calibrated than if I take the trouble to preserve the SRAM contents. 3) The adjustments are I believe software, so there's no risk that adjusting potentiometers will cause drift to increase. 4) I don't have any historical data from cal certificates, so even if I a range is in error by 0.5%, I can't make any attempt to estimate the drift over time. Clearly if I had cal certificates over a period of years, I maybe able to get some idea of how the instrument is drifting, so possibly correct for that, if it is drifting in one direction. Thoughts? Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK. Registered in England and Wales, company number 08914892. http://www.kirkbymicrowave.co.uk/ Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please) ___ 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] Fall of SRAM voltage in a 3457A without external power
On 25 January 2016 at 11:50, Poul-Henning Kamp wrote: > > In message < > canx10hcamahhhxqiao9bdzu03c2bbt787mr10rmnywk3oa8...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >ESD and leakage of the human body would probably make screw this up, so > I'm > >not suggesting replacing the battery that way if you want to preserve the > >contents of the SRAM, but there's a fairly good chance the contents would > >remain in RAM if one was reasonably quick, especially if you topped the > >voltage up from the mains just before removing it from the chassis. > > I usually hook up a separate battery while doing such surgery. > Yes, it is the logical thing to do, but there's a reasonable chance one could get away with it, but obviously if its important to keep the data, one would use an external supply. I'm tempted to purposely let the data become corrupted for the reasons I gave in another thread. Dave ___ 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] Fall of SRAM voltage in a 3457A without external power
In message , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: >ESD and leakage of the human body would probably make screw this up, so I'm >not suggesting replacing the battery that way if you want to preserve the >contents of the SRAM, but there's a fairly good chance the contents would >remain in RAM if one was reasonably quick, especially if you topped the >voltage up from the mains just before removing it from the chassis. I usually hook up a separate battery while doing such surgery. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Fall of SRAM voltage in a 3457A without external power
I decided to try a little experiment on my 3457A, When on mains the SRAM gets 4.8 ~ 5 V. This does not seem to be well regulated, so I assume depends on mains voltage. Once power is removed, the voltage on the SRAM stays well above the battery voltage for some considerable time, which I assume is due to a decoupling capacitor. My 10 M Ohm input Z multimeter is loading the circuit too much to continuously monitor the voltage, but a few checks indicated the voltage across the SRAM is falling quite slowly. Starting at 4.8 V from mains power, after 23 minutes of no mains power, the voltage on the SRAM was at 3.4V, which is above the battery voltage (3.03 V). and well above the 2.0 V needed to hold the SRAM contents. Assuming the SRAM takes a constant current one would expect the voltage to fall linearly with time. If so, it would take 46 minutes to fall to 2.0 V even without battery power. ESD and leakage of the human body would probably make screw this up, so I'm not suggesting replacing the battery that way if you want to preserve the contents of the SRAM, but there's a fairly good chance the contents would remain in RAM if one was reasonably quick, especially if you topped the voltage up from the mains just before removing it from the chassis. Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK. Registered in England and Wales, company number 08914892. http://www.kirkbymicrowave.co.uk/ Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please) ___ 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] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter
On 25 Jan 2016 03:51, "Tom Miller" wrote: > > Looking through the service manual I don't see a connection from the battery to the NVRAM. I am sure I measured battery voltage on pin28 so I suspect a schematic error. Can someone that has one open verify that? My 3457 is in cal and I prefer not to break the seals. NVRAM (non-volatile random access memory), an example of which is flash ram, doesn't need any power source to hold the data. The 3457A has SRAM (static random access memory), which does. Using my old Tektronix 4.5 digit multimeter I definitely measured a voltage on positive voltage on pin 28 which was around 200 mV less than the battery. I believe it must be via a high impedance path as my meter, which I assume is 10 M Ohm input impedance, is loading the circuit and so one sees the voltage drop slowly although the battery voltage doesn't change. When I put the mains power on, the voltage on the SRAM rose to about 4.8 V. When the mains power is removed the voltage stays well over 4 V but gradually drops in voltage. I assume that a decoupling capacitor has been charged to 4.8 V, so the voltages across the SRAM doesn't immediately fall back to 2.8 V. Without having acess to an electrometer or other very high input Z multimeter I could not say for sure, but I suspect that if one was fairly quick (of the order of minute or two) one could probably just cut the old battery out, solder a new one in, without loosing the contents of the SRAM. But one would not want to take that chance if one considered it was important to keep the data. I am actually thinking whether it is better for *me* to actually purposely let the SRAM contents be lost, but my reasons for this world form another thread. Dave. ___ 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.
