Like my 428 also. But I have a tube version hybrid. It is drifting a bit and one day I will get off my butt and address that. But its not bad enough to open the case actually. Using the ad588 as a current source is a good idea but semi expensive. I looked up the ad558 yesterday and digikey wants $38 each.
On Wed, Jan 13, 2010 at 11:26 AM, Michael Baker <[email protected]> wrote: > Hello, TimeNutters-- > > Oops!! I goofed-- > > I meant to say HP/Agilent 428B Sensitive Clip-On DC Milliammeter. > > Only the latest revision model with a serial number > prefix of 995-xxxxx is worth having. > In their last revision, HP retained a couple of tubes in functions > where they felt early 80's transistors would be less reliable. > However, most of the circuitry is solid state and is all on a > very nice printed circuit board. The unit went out of production > in 1984. The probes are extremely fragile and if dropped > or exposed to excessive heat for long periods of time > the ferrite cores or the Mu metal shields will be degraded. > > The manual warns against storing the probe on top of > any hot instrument top. My 428B has been an invaluable > and frequently used test instrument on my work bench. > Alignment was a little tricky but once done, my unit > has been in use for over 10 years with no problems. It is very handy for > measuring low current drains of > circuits down around the 1 to 10 milliamp range. Actually, > on the lowest scale (0 to 1mA) you can accurately measure > currents down to 0.1mA. > Mike Baker > ---------------------------- > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
