On 25 January 2016 at 11:12, Dr. David Kirkby (Kirkby Microwave Ltd) < drkir...@kirkbymicrowave.co.uk> wrote:
> 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 > <snip> > Thoughts? > Someone sent me a private email, saying that if by purposely removed the power from the SRAM caused the 3457A to fail its self-tests, which is may well do, then Keysight may consider the 3457A needs repair, and so offer a fixed-price repair. Hence my "trick" to get this calibrated as accurately as possible would have backfired, and I'd be out of pocket. In fact, on a 3457A, the fixed-price-repair would probably cost more than the instrument is worth, as these are not worth a lot now. Hence I would not do this before getting clarification from Keysight. It might be possible to get them to set it right, even if within spec, but I think their calibration routines are very automated, so its probably not so easy to get a special calibration, whilst paying for their cheapest calibration service. 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.
