Author Topic: Fluke 382A Reference Board  (Read 496 times)

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Offline rajeshvsTopic starter

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Fluke 382A Reference Board
« on: November 03, 2024, 03:17:52 pm »
Hello Everyone,

I’m looking for a manual or parts information for the Fluke 382A. The reference board (382A-401) in my unit is different from what is described in the available online manuals. I have checked various sources, but most of them only cover the older reference board version(313A-418).

I have two burned resistors on my board:

    R123 – Burned
    R114 – Half baked, perhaps 470Ω?
    This issue is likely caused by CR106 Zener (?) too.
2423927-0

If anyone could share a photo of a good reference board, or share the component values, or provide a schematic/manual for this revision, I would greatly appreciate it.

Thank much in advance!
 

Offline wn1fju

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Re: Fluke 382A Reference Board
« Reply #1 on: November 04, 2024, 12:34:42 pm »
Here is a picture of the reference board.

R123 looks to be brown-orange-red and measured 1.3K in circuit.

R114 looks to be yellow-violet-red and measured 4.5K in circuit.

CR106 looks to be a 6V Zener, measured by putting 5ma across it from a current source and measuring the voltage drop (not precise).

I hope this helps.  This piece was buried under 10 pieces of heavy test equipment and a pain in the back to get to!!!

 
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Offline rajeshvsTopic starter

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Re: Fluke 382A Reference Board
« Reply #2 on: November 04, 2024, 08:36:41 pm »
Wow, this is great—you made my day!

Thank you so much, wn1fju, for your time and effort. I really appreciate it.
 

Offline rajeshvsTopic starter

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Re: Fluke 382A Reference Board
« Reply #3 on: November 04, 2024, 11:10:57 pm »
Since I'm at it, here’s an internal pic. The reference diodes are buried deep inside. The failed resistors are part of the oven temperature sensing circuit.
 

Offline DG5NGK

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Re: Fluke 382A Reference Board
« Reply #4 on: November 14, 2024, 03:30:27 pm »
I can confirm this, see picture below taken from my 382A with SN 82906

Could measure slightly different values:
R114: 4.7kOhm+-10% according to the color code, measured 4.26kOhm in circuit. (4.40kOhm with Q106 removed)
R123: 1.3kOhm +-10% according to the color code, measured 1.29kOhm in the circuit.

I assume the board from wn1fju was previously repaired? I can see some differences at R109, Q106, C102 and C103.
My PCB looks untouched. The protective varnish is present on all solder joints.

It would be nice if someone could provide the schematic and parts list for the 382A-401 master ref module.
Or a more recent user manual for the 382A. My last one is dated November 1, 1964 and is from SN 240.
It shows updates up to SN 300 (code W) and SN 325 (code U)

Interestingly, there is an auction with SN 326 (www.ebay.com/itm/355750647388)
It already appears to have no R8 calibration trimmer on the back. But it still has the labeling for it. So it should already have the 382A-401 inside. But maybe it was replaced later.
And there's one with SN714 (www.ebay.com/itm/266783594476)
This one looks pretty shiny, and also has the 382A-401 in it.

Maybe someone can take a look at the 383B user manual? It might contain the same reference module, as it is very similar to the 382A.
 
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