Fluke 931B RMS differential voltmeter

[tatel]

Hi, I got this Fluke 931B from Ebay. I just converted it to operate on 220 230V. Using a 200 mA fast fuse until I receive the correct 125 mA one.

It looks pretty near specification at first glance but:

1) Push to cal seems to do nothing? You can see a fast video here https://youtu.be/1rnkch9M4vw

2) It came without any battery cells, does somebody know what could be used? I would probably like to use Ni-Cd cells since I want the trickle charge to work. However manual does not say which cells should be used

I'm using this manual, which seems to be for 931A(B) and 931P(B): https://archive.org/details/manualsplus_01105

Artek Manuals does list a manual for 931B, I ordered it but I haven't received the download link yet (there's some health issue there, so I'll have to wait)

What worries me the most at this moment is that Push to cal thing. Any hints would be greatly appreciated

[The Soulman]

1) Push to cal seems to do nothing? You can see a fast video here https://youtu.be/1rnkch9M4vw

Try to push instead of pull?

[tatel]

 

It can't be pushed, perhaps 20 thou... about half a milimeter, or even less, and it does nothing, either.

https://youtu.be/_0i7FePU0yw

[Runco990]

I'll give you a hint.  Have you considered that this is a mechanical issue of some sort?  You may have to actually remove the cover to actually LOOK at the switches and how they work.  I'd bet it's something stupid simple.

[tatel]

Yep. I'll probably do exactly that as last resort. However I hope there's some people here experienced with these devices, that could perhaps know what's going on.

[tatel]

I'll give you a hint.  Have you considered that this is a mechanical issue of some sort?  You may have to actually remove the cover to actually LOOK at the switches and how they work.  I'd bet it's something stupid simple.

You were right, of course. It turned out, contact spring was put out of place. Just to undo the grub screws on that clutch mechanism, adjusting position of the two rings, and placing the spring between the two rings, has been enough.

https://youtu.be/V7V2p3v0VjM

[ken goodhew]

Hi Tatel,
Did You get the Fluke 931b service manual from Artek?
Does it include all the circuit diagrams as the Manual plus online version appears to be missing one of the circuit diagrams.
They only show 2 whereas i think there should be 3.

[tatel]

Hi Tatel,
Did You get the Fluke 931b service manual from Artek?
Does it include all the circuit diagrams as the Manual plus online version appears to be missing one of the circuit diagrams.
They only show 2 whereas i think there should be 3.

Unfortunately not. Actually I have emailed them quite a few times, but didn't got any answer since September, 18th. Still waiting. Other people is saying they got the manuals he ordered in about one hour, but two of us were not so lucky.

Please see this thread: https://www.eevblog.com/forum/repair/anyone-heard-from-artek-manuals/

[lowimpedance]

Hi Tatel,
Did You get the Fluke 931b service manual from Artek?
Does it include all the circuit diagrams as the Manual plus online version appears to be missing one of the circuit diagrams.
They only show 2 whereas i think there should be 3.

Hi, I got this Fluke 931B from Ebay. I just converted it to operate on 220 230V. Using a 200 mA fast fuse until I receive the correct 125 mA one.

It looks pretty near specification at first glance but:

1) Push to cal seems to do nothing? You can see a fast video here https://youtu.be/1rnkch9M4vw

2) It came without any battery cells, does somebody know what could be used? I would probably like to use Ni-Cd cells since I want the trickle charge to work. However manual does not say which cells should be used

I'm using this manual, which seems to be for 931A(B) and 931P(B): https://archive.org/details/manualsplus_01105

Artek Manuals does list a manual for 931B, I ordered it but I haven't received the download link yet (there's some health issue there, so I'll have to wait)

What worries me the most at this moment is that Push to cal thing. Any hints would be greatly appreciated

Scans of the Fluke 931B schematics attached.
(From my own original manual)

[tatel]

Well, I finally got it. Turns out, it was sent to me on November, 19 the day I opened a PayPal dispute, which was resolved that very same day. I just found it on my spam folder half an hour ago. So I sent back the refunded amount, but even now, Artek contact webform doesn´t work. I'm a little bit fed up with all those contact problems by now, and since the money is sent, I'm not going to try and contact again.

About the schematics in that manual, I can confirm they are exactly what @lowimpedance kindly uploaded.