Back on this project, sorry for the late post I was on vacation and work was driving me crazy!
Have they tested the 2W 100 Ohm range on the rear jacks, as proposed?
Yes, and the value is drifting as well, see my previous post.
Since the "Cal Error 707" is fixed I opened a new post in the repair section for the drifting 100 Ohm range only in the 2W R mode:
https://www.eevblog.com/forum/repair/hp-34401a-drift-in-the-2w-r-mode-in-the-100-ohm-range/Here now the surprise bomb, check this last mail email from the cal lab:
We recently received another 34401A in that has the same issue with the ohms function as your did. Would you be insterested in trying to fix it for us. If you do we can work out some kind of deal with the calibration. Let me know if this is something you'd be interested in? If not, I understand, I will just send your unit back.
So now I got two units to repair! Yes, I love to repair stuff! After a quick check on this unit, it seems there is a lot to do here, see below the self test results:
-> SYST:ERR?
<- +612,"Ohms 500 nA source failed"
-> SYST:ERR?
<- +613,"Ohms 5 uA source failed"
-> SYST:ERR?
<- +615,"Ohms 10 uA source failed"
-> SYST:ERR?
<- +617,"Ohms 100 uA source failed"
-> SYST:ERR?
<- +618,"DC high voltage attenuator failed"
-> SYST:ERR?
<- +619,"Ohms 1 mA source failed"
-> SYST:ERR?
<- +621,"AC rms full scale failed"
Jeeeeee...
this unit is almost fried! I started a new post
https://www.eevblog.com/forum/repair/hp-34401a-error-612-613-615-617-618-619-621/on the repair section as well.
Stay tuned,
Z
EDIT: Title switched to solved.