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Products => Test Equipment => Topic started by: iXod on July 29, 2020, 01:12:22 am

Title: Recommendation for someone to repair HP 34401A DMM?
Post by: iXod on July 29, 2020, 01:12:22 am
Displayed voltage is a floating value not related to the input value.

Recommendations for a repair service?

Thanks.
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: Kean on July 29, 2020, 01:31:40 am
It might help if you state your location, or set it in your profile.
You could of course try Keysight, while it is a discontinued model they do still provide service for it.
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: iXod on July 29, 2020, 02:30:06 am
Profile update: Done.

Thanks, I'll ping Keysight.
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: bdunham7 on July 29, 2020, 02:37:19 am
Quote from: iXod on July 29, 2020, 01:12:22 am
Displayed voltage is a floating value not related to the input value.

Recommendations for a repair service?

Thanks.

Can you elaborate on that?  If you connect a 9 volt battery to the leads it just reads whatever?  Is this a new-to-you unit?
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: hugo on July 29, 2020, 02:45:14 am
If you feel adventurous ...  ;)

https://xdevs.com/fix/hp34401a
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: coromonadalix on July 29, 2020, 09:44:32 pm
Do a self test and report

https://www.youtube.com/watch?v=cPUt9p-pdZQ (https://www.youtube.com/watch?v=cPUt9p-pdZQ)
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: Dr. Frank on July 30, 2020, 01:08:51 pm
Quote from: iXod on July 29, 2020, 01:12:22 am
Displayed voltage is a floating value not related to the input value.

Recommendations for a repair service?

Thanks.

We (the eevblog community) have repaired many 34401A remotely. For this failure picture, there might be already a few possible and known root causes: front/rear switch, input relay, protection resistors.
You need to test more precisely, which modes, ranges and configurations do fail.
Please go through the other modes, as DCV ratio, 2W/4W Ohm, Ampere, ACV and test if that's floating also.
Also check, if the rear jacks are operational.
What about 10V reading in 100V range?


Quote from: iXod on July 29, 2020, 02:30:06 am
....

Thanks, I'll ping Keysight.

This solution is BER.


Frank
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: coromonadalix on July 30, 2020, 02:21:02 pm
The front rear switch may play tricks, and you have an internal fuse socket near the rear terminals ...   thats why as written above,  you have to test all the modes

The self test may point to some problems
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: Jwalling on July 30, 2020, 02:59:38 pm
Quote from: iXod on July 29, 2020, 02:30:06 am
Profile update: Done.

Thanks, I'll ping Keysight.

I'll bet it's more than a used one would cost. I wouldn't bother...
An exchange is $822.
https://service.keysight.com/infoline/public/product-service.aspx?laf=mya&pn=34401A&lc=eng&cc=US (https://service.keysight.com/infoline/public/product-service.aspx?laf=mya&pn=34401A&lc=eng&cc=US)
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: coromonadalix on July 31, 2020, 12:34:07 am
822$    wtf ????  wow     just buy an used working one ???     :palm:
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: WattsThat on July 31, 2020, 12:42:21 am
Quote from: coromonadalix on July 31, 2020, 12:34:07 am
822$    wtf ????  wow     just buy an used working one ???     :palm:

Or just pony up another $200 and buy a new 34460/1A.
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: MathWizard on July 31, 2020, 12:49:41 am
So on average, if 1 of these break, how repairable are they, if you don't have a 2nd for parts ?

I'm sure I'd love 1, but add on the calibration cost, tx/sh, and it looks a lot worse, than a newer model.
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: alotvac on July 31, 2020, 01:36:39 am
Quote from: WattsThat on July 31, 2020, 12:42:21 am
Quote from: coromonadalix on July 31, 2020, 12:34:07 am
822$    wtf ????  wow     just buy an used working one ???     :palm:

Or just pony up another $200 and buy a new 34460/1A.

Or, a used 34465A directly from Keysight? $1,080.80 (with make offer, possibly another 10% - 15%)

Keysight Used 34465A Digital multimeter, 6 1/2 digit, Truevolt DMM https://www.ebay.com/itm/Keysight-Used-34465A-Digital-multimeter-6-1-2-digit-Truevolt-DMM/174367518510?hash=item28991d2f2e:g:DvwAAOSwgJpfICWR (https://www.ebay.com/itm/Keysight-Used-34465A-Digital-multimeter-6-1-2-digit-Truevolt-DMM/174367518510?hash=item28991d2f2e:g:DvwAAOSwgJpfICWR)
Title: Re: Recommendation for someone to repair HP 34401A DMM?
Post by: Jwalling on July 31, 2020, 08:52:38 am
Quote from: coromonadalix on July 31, 2020, 12:34:07 am
822$    wtf ????  wow     just buy an used working one ???     :palm:

Yep. And keep the old one for parts, if the OP can't fix it.