[volt-nuts] Fluke 732A schematic re-drawn?

David C. Partridge david.partridge at perdrix.co.uk
Sat Jan 20 15:55:03 EST 2018


Actually I wasn't speculating on the absence of Q14, though the manual you emailed me explained why that happened (A8 board added).

I was more concerned about the way the A5 reference schematic was drawn makes it harder to understand.

Thanks
Dave

-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces at febo.com] On Behalf Of Bill Gold
Sent: 20 January 2018 19:06
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 732A schematic re-drawn?

David:

    I will be guessing that you are discussing the lack of Q14 that is chassis mounted on some versions of A4, driven by Q13.

    I have sent you by PM a pdf of a 732A manual that I probably got from FLUKE.
If you look at the schematic for A4 this one has the chassis mounted Q14 shown and listed in the parts list for A4.

    The interesting thing here is that a manual I sent you is P/N
645051 dated May 1983, while another manual P/N 788414 dated May 1986 does NOT show Q14.
So for some reason known only to the people at FLUKE Q14 must have been dropped by May 1986.  Go figure.

    I don't have any other manuals except those two P/Ns.  The best I can figure out at this time is that Q14 was dropped between A4 Rev A and A4 Rev D.  According to the parts list in the May 1986 manual Q13 is a 2N3906.  The Ic maximum is 200 ma.  I know that the overall current draw from the batteries when no AC power applied is about 250ma, but I don't know how much of that is for the heaters.

Bill


----- Original Message -----
From: "David C. Partridge" <david.partridge at perdrix.co.uk>
To: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
Sent: Friday, January 19, 2018 4:16 AM
Subject: [volt-nuts] Fluke 732A schematic re-drawn?


> The schematic for the A5 Reference and Oven Controller Board has to be one
> of the worst schematics I've seen in a while, breaking pretty much all the
> rules on making a schematic understandable.  I suspect this was done
> deliberately.
>
> Has anyone ever re-drafted this (to include the A4 pass transistor
> components) to make sense of it?
>
> May your volt always be stable
> Dave
>
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