[volt-nuts] Fluke 332B

Bill Gold wpgold3637 at att.net
Sat Jul 8 10:03:49 EDT 2017


    The 332D and the 332B are identical except for the accuracy specs for
the stability of the output voltages.

    332B spec for 10 Volts is +/- .002% (20 ppm) for 90 days while the 332D
spec for 10 Volts is +/- .001% (10 ppm) for 60 days.  The monthly drift
specs are also slightly better on the D than the B.

    I suspect that FLUKE simply aged and selected a more stable reference
device along with matching the resistors in the sampling string for less
drift.  For all of that you paid US$2,595 for the 332B and US$2,995 for the
332D in 1973.

    I seem to remember someone replacing the chopper assembly with something
a little more modern.  Don't know where I saw that.  I have a B and a D and
both seemed to be very stable with the existing chopper assembly.

    One thing I did find is that the electrolitic caps have a high tendency
to go bad.  Not the big ones on the raw supply but those on the various plug
in assemblies.  I seem to remember that they were in a range of 1 ufd to 47
ufd or so.  So check them all or better yet just recap.  You will save
yourself a LOT of troubleshooting time in the long run.  There is also a
discussion of this subject either on VoltNuts or EEVBLOG.


----- Original Message ----- 
From: "David C. Partridge" <david.partridge at perdrix.co.uk>
To: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
Sent: Saturday, July 08, 2017 5:09 AM
Subject: [volt-nuts] Fluke 332B

> Amongst the stuff I recently acquired is a Fluke 332B (sn 4151).
> I found the manual for the 332D on the Fluke website, but can't find one
> specifically for the 332B apart from an incomplete US Army version.
> I have some questions:
> 1) Does anyone know where I can find the matching manual
> 2) If not, how useful is the 332D manual?
> 3) It was last calibrated in 2010, and appears to be consistently low in
> output (about 5mV at 100V, 25mV at 500V, 50mV at 1000V) after being on for
> an hour.  Is that the sort of error I should expect after that period?
> 4) I'm leery of the chopper amp, did anyone (Dr. Frank?) do a retrofit
> a modern chopper op-amp or similar?
> Thanks
> Dave
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