Frank, Have you got a link to the eevblog Datron 4910 reference element decryption? I have a 4910 and am curious to see what they found, but am not finding any reference to it in their "Episode" list.
Thanks Steve On Aug 20, 2013, at 12:01 PM, Frank Stellmach <[email protected]> wrote: > Hello, > > until now, nobody has ever reenginered the 732B schematics. Perhaps the > bbs.38hot colleagues (lymex et. al.) have done that, but I do not get access > to the forum for downloading anything, either. > > But on eevblog, the Datron 4910 reference element has been decrypted > completely, as now the content of the Vishay resistor array is known. > Yep, I have to admit, that I also have made much more effort there than here > lately. See 'Ultra precision reference LTZ1000'. > > Anyhow, in the 732B manual, there is that circuit block diagram, showing the > usual reference amplifier circuitry. > Fluke added some current cancellation circuitry compared to the 732A, and has > put all temperature sensitive components inside the oven. > That includes especially the 4-5 precision wirewound resistors around the > ref. amp., which cause the most drift over temperature and time. > > I think that's all with 732Bs magic. > > The 732B had two series, one earlier with the SZA263 (Motorola) and after > termination of that part, a compatible 2nd source from LT, the LTFLU refence > amplifier. > > The mentioned Fluke / Deaver document analyses the different drift behaviour > of those two components, but in general, the 732A (based on the SZA263) was > less stable, afaik. > > Frank > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
