[volt-nuts] Fluke 732A Questions

J. L. Trantham jltran at att.net
Sun Dec 29 13:12:14 EST 2013


Thanks for the info.

Looking at the Hypertronics catalog, it would appear that the panel mounted
socket (with male, solder cup, pins) is:


And the mating plug would be:


However, the dimensions are a bit off and the appearance of the panel
mounted socket is not the same as what is on my 732A, J10, on the back of
the 732A-7005 battery module.  My connector is exactly as shown in the
change sheets with a dimension of 0.475 inches side to side and 0.500 inches
top to bottom (as viewed from the back of the unit) rather than 0.512 x
0.512 as suggested in the catalog.

However, the diameter of the mounting hole and the presence of a 'notch'
appears to be as shown in the catalog, thus suggesting that it, indeed, is a
series D01 part.  The diameter of the threaded part of J10 is 0.410 inches
and the catalog calls for a hole diameter of 0.441 inches.

One other observation is the presence of a 'symbol' on the bottom edge of
the socket (as viewed from below) that looks like a stylized 'FRE',  The 'F'
perhaps could be an 'A' and the 'E' perhaps could be a 'B'.  The symbol
starts low and ends low with a 'peak' of the symbol in the middle of the
'R', sort of a 'roof' shape to the top of the symbol and flat on the bottom
of the symbol.

Not sure what that means but I have a picture of it if anyone thinks it
would help.  It does not look like the stylized 'H' symbol shown in the
Hpertronic catalog.  Perhaps the company was something else before they
became Hypertronics.

I looked through the change sheets for the 732A and could find no mention of
the value of the thermistor resistance at temperature, only comments about
what its stability should be.  Knowing that you have a value in the mid 4K
range is reassuring.  My S/N starts with 3.

Right now, it indicates 10.0000005 VDC on the 3458A and 4230 ohms on the
Fluke 8050A.

Thanks for your help.


-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of R.Phillips
Sent: Sunday, December 29, 2013 8:40 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 732A Questions

Hi Joe
I also obtained a Fluke 732A back in October last, and I have fitted a new
set of SLA batteries and it is working just fine - I am still very impressed
by its accuracy and stability, and its build quality.
First, the external 3-pin power socket is a HYPERTRONICS 'D' type connector
(female) type 100-166 - but I have not found one to date !
I also expected the temperature monitoring thermistor to give a 3 to 4 K
ohms, as indicated in the manual P/N 645051 dated May 1983 - but I guess
that you have a later model as I do, mine being serial # 4845***, some
modifications were made,and I understand that this included a change of
thermistor, so the standard reading is in keeping with your result. My unit
gives a very stable 4.520 K ohms, being between 4.52080 and 4.52090 K ohms. 
Judging by your findings, you are also using the 1983 copy of the User
Manual - we could both use a more up to date issue.
I am awaiting the repair of my 3458A - so I am having to rely upon a
recently calibrated Keithley 2015 and my good old 3456A - but they both give
very impressive results - The Keithley giving 1.000007 volts for the 1 volt
output, and 10.00000 volts for the 10 volt output (how I miss that final
Looking forward to your further results and any other owners comments.
Best regards


-----Original Message-----
From: J. L. Trantham
Sent: Saturday, December 28, 2013 10:51 PM
To: volt-nuts at febo.com
Subject: [volt-nuts] Fluke 732A Questions

I have reviewed the prior postings on Volt-nuts (a very rewarding review,
BTW)) regarding the 732A and have two questions:

1.        Has anyone determined the part number, or a source, for the mating
plug to J10, the external power connector for the 732A-7005 battery pack?  I
noted some postings recently about this but did not find a definitive
response regarding the identity of this plug.  The alternative would appear
to be a complete replacement of J10 and its plug, as long is it all fits in
the opening in the panel.  I hate to 'bore holes' in vintage equipment.

2.       The oven thermistor in my 'new to me' unit measures 4229 ohms (+/-
an ohm or two) after the unit has warmed up for a week or so.  I note the
manual refers to 3K to 4K for the value of this thermistor when the unit is
'stable' as well as other's posting values in the mid 3500's ohms for their
units.  Should I be concerned?  The unit seems to be stable to within about
2 uV over about a week (as measured by my 3458A - see below).  Should I open
the unit and try to measure the oven temperature or just be satisfied that
the unit seems to be working?

I had to replace the four 6V 4AH SLA batteries and they charged up
appropriately as judged by the front panel LED's.  I had to remove the
'jumper' for the '40' option on the A7 board and connect the jumper to the
'20' and '10' options (total of '30') in order to get the unit to adjust to
10.0000000 VDC on my 'Agilent In Cal'd' 3458A.

The need to change the jumpers, perhaps, could be just an ageing issue or,
on the other hand, a 'temperature' issue with the oven.

Should I open the unit and directly measure the temperature (supposedly
about 48 degrees C) or just be satisfied with what I have?

My recently added 735C also needed moving some 'jumpers' in order to get it
'on scale', as determined by my 3458A, although it's thermistor measures
about 3330 ohms (after being on for several weeks).

Thanks for everyone's help.


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