Bill, With six 732B's, you certainly qualify as a volt nut.
Joe Gray W5JG On Aug 20, 2013 10:37 AM, "Bill Gold" <wpgold3...@att.net> wrote: > Joe: > > The 731A and 731B were run at room temp and therefore were subject to > room variations. They both use the same "Reference Amplifier" as the 732A > & B use. I have one 731B and it is amazingly stable for the room temp > variations I experience at home. When I was working we had a 731B that was > also very good. I had sent it for calibration over a 10 year period and > the drift was equal to, or better than the 732 series. At the end of the > 10 years it was absolutely stable at less than 1 ppm. This was all being > done at a Fluke Service Center that was located in Milpitas California, and > their 732As were being routinely sent to Fluke in Everett WA. > > The difference between the 731 & 732 is that starting with the 732A > all of the temperature sensitive components were enclosed in a oven > assembly that had heaters surrounding the oven enclosure which is running > at 45 degrees C. This includes all of the resistors and adjustment pots. > I have torn down a 732A to the oven assembly and gone inside the assembly > to replace a component. It is a real trick to do this, but by being > careful it can be done. > > The fact that the 732As have been in operation for a much longer > period of time probably explains the lower drift rates than the 732Bs. The > 732As have been "aged" much longer. I know people who prefer the 732A over > the 732B because of this. The only problem with the 732A is that the > heaters use more power than the 732Bs. Early manuals spec 24 hour battery > operation, but later manuals have changed that to 12 hours. All of the > 732As I have observed will only run for about 12 to 15 hours before the "in > cal" light goes out meaning that the batteries have dropped below about 22 > volts. The 732B is speced at 72 hours battery operation but I have no > experience if this is true. > > I guess I am a real "Volt-Nut" in that I have 6 732As at home right > now. I inter-compare them once a week. The last time I was able to verify > what the official "volt" is was in 2005. Right now I need to find a good > Cal Lab in the South SF Bay Area where I can have one of them "certified" > against their traceable standards. The Fluke service center was closed > years ago. > > Bill > _______________________________________________ > 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.