[time-nuts] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
I once got in around 20 Tek DM5?? GPIB DVM modules for the TM5000 series mainframes. They have a rechargeable nicad pack soldered to the circuit board. All the meters still had good cal data but the cells were on their way out. The meters are a pain to re-calibrate... I used a DIP clip to provide voltage to the SRAM chip while changing the battery. Only lost cal dataon one meter.I replaced the nicads with a CR123 lithium cell with a series diode to block the charging current. On each meter I checked the standby current to the SRAM first. A couple had rather high values that would drain the CR123 after a year or so, so I kept nicads in those. After 5+ years the meters are still working on the CR123 cells. ___ 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] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
Not only battery backed up SRAM but EEPROM config data has problems. I'm a bit of a mass nut and have seen lots of old precision balances (i.e. Sartorious and Mettler) that used first gen serial EEPROMs to save their cal/config data. Lots of these are going senile. I had to build programmers for the SDA2006 and MCM2801 (?) chips since no commercial programmers support them. They require 3 or 4 different voltages to program. Whenever I get in a scale I dump the old eeprom and rewrite it. If the old eeprom already croaked, I use a backup dump from a different scale. Sometimes that causes issues if the scale has an internal cal weight that was calibrated at the factory... then one gets to try and adjust the internal cal weight to match the weight specified in backup device data. ___ 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] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
Hi The coin cell / backup battery swap out is something we probably will become more familiar with on a *lot* of gear. The battery backed up RAM idea is now old enough that there is a large population of test gear / radios / telecom gear out there with this “feature”. In some cases the loss of the battery is a temporary issue. In a lot of others it’s a significant problem. If you are buying a piece of gear that has important stuff in RAM, the big question is — has the data been lost already? I have bought gear that had a good battery in it, but bad data. If the gear comes up with “data lost” on the screen, that’s easy to spot. In most cases …not so easy at all. Some gear might be configurable by normal means. Almost everything I’ve seen needs a “factory only” shoot from a test set that probably no longer exists. Yes, there’s nothing magic in that test set. The RAM just has bits in it. Figuring out what all the bits need to be without any documentation is not easy. One might hope that as the gear becomes obsolete, the information about what’s what would be released to the public. Based on … errr …. on the job experience - not so likely. The data rarely is documented in a “public compatible” fashion. One guy’s notes tell you what the test setup looks like. Another set of notes go into the code. Both are buried in log books from who knows when. Beyond this, someone actively has to agree to release “corporate IP”. The complex part of that is the fact that the calibration techniques probably live on in a modern piece of gear. Not at all easy …. Bob ___ 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] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
Not necessarily, if you follow the service manual's procedure, you can replace the backup 3V cell safely, keeping the calibration data: the problem is checking periodically the backup cell or replacing it regularly (say, every 5 years). On Tue, Nov 17, 2015 at 12:33 PM, davidh wrote: > > > Hi Angus, > > I have three 6681s operating concurrently under a single instance of timelab > beta. It operates perfectly, even live n-cornered measurements. Kudos to > John! > > The only downside (and I understand why it's this way) is that each counter > needs a unique GPIB interface, but this is a timelab requirement and nothing > to do with the counters. > > My only fear regarding the counters is that I'll lose the cal one day, so > I'm keen to discover how we can calibrate them ourselves. > > Cheers, > > david > > > On 17/11/2015 7:32 AM, Angus wrote: >> >> Hi, >> >> PM6681's turn up at quite a good price too, and you get a lot of >> extras over the 6680 - does anyone know if Timelab will work with a >> 6681? >> >> Angus. >> >> >> >> On Sun, 15 Nov 2015 15:10:42 -0800, you wrote: >> > > > > ___ > 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] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
Not necessarily, if you follow the service manual's procedure, you can replace the backup 3V cell safely, keeping the calibration data: the problem is checking periodically the backup cell or replacing it regularly (say, every 5 years). On Tue, Nov 17, 2015 at 12:33 PM, davidh wrote: > > > Hi Angus, > > I have three 6681s operating concurrently under a single instance of timelab > beta. It operates perfectly, even live n-cornered measurements. Kudos to > John! > > The only downside (and I understand why it's this way) is that each counter > needs a unique GPIB interface, but this is a timelab requirement and nothing > to do with the counters. > > My only fear regarding the counters is that I'll lose the cal one day, so > I'm keen to discover how we can calibrate them ourselves. > > Cheers, > > david > > > On 17/11/2015 7:32 AM, Angus wrote: >> >> Hi, >> >> PM6681's turn up at quite a good price too, and you get a lot of >> extras over the 6680 - does anyone know if Timelab will work with a >> 6681? >> >> Angus. >> >> >> >> On Sun, 15 Nov 2015 15:10:42 -0800, you wrote: >> > > > > ___ > 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] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)
Hi Angus, I have three 6681s operating concurrently under a single instance of timelab beta. It operates perfectly, even live n-cornered measurements. Kudos to John! The only downside (and I understand why it's this way) is that each counter needs a unique GPIB interface, but this is a timelab requirement and nothing to do with the counters. My only fear regarding the counters is that I'll lose the cal one day, so I'm keen to discover how we can calibrate them ourselves. Cheers, david On 17/11/2015 7:32 AM, Angus wrote: Hi, PM6681's turn up at quite a good price too, and you get a lot of extras over the 6680 - does anyone know if Timelab will work with a 6681? Angus. On Sun, 15 Nov 2015 15:10:42 -0800, you wrote: ___ 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.
