Products > Test Equipment

[SOLVED] 34401a - Cal Error 707

<< < (5/6) > >>

Dr. Frank:
It's a guess only, from remote.  But  it would explain the gain error.

Well, I like Italian beer, so I would like to accept your offer, if my guess turns out to be correct.
????????????????

Frank

Zucca:
Here the reponse from the Lab:


--- Quote ---Sorry for the delay. The lab has been slammed. Unfortunately, the rear terminals could not be calibrated either. The 100 ohm test is still the one failing and cannot be pulled into tolerance.
--- End quote ---

They will now send me the unit back as it is and I will investigate what´s going on.

It is becoming interesting now... stay tuned!

free_electron:
that string ofd resistors is troublesome. i've had a number that came loose over time.
sometimes resoldering doesnt help. you need to replace em.
The electrode plating cracks off the body. resoldering bridges the crack but they crack in another spot later...

mimmus78:
Yes replace those resistors, I had the similar problem on a K2000 ... just reflow did not worked. I'm starting thinking Keithley and HP used the same resistors parts and they just go wrong after few years.

Dr. Frank:
Have they tested the 2W 100 Ohm range on the rear jacks, as proposed?

For the rear channel, there is also a different set of protection resistors involved, therefore if the problem lies there, it could also vanish on the rear.

Otherwise, the lab people are not very clever..

Frank

Btw:
Those 3x24k  resistors (R170-172, R180-182) are not at all involved in 2W Ohm mode, but in 4W Ohm only.
Follow the H, L marked lines in the schematic, p. 155 and 156:

The parts in serial with the DUT and therefore possibly affecting 100Ohm range 2W Ohm are:
- Input Jacks and its soldering
- Switch S1A, S1G (FRONT/REAR), most probable, => Label HI
- Label HI => K101 (switches OHMS_CURRENT)

The node between K101,3 and L101 is the high Kelvin Point for the Ohm function, as over L102, K103 to DCLO the DUT voltage is measured. Therefore, only the 3 mentioned parts may influence the 2W function.

If the 2W current source is not ok, (not very probable), this could be measured by monitoring the ohm current by another DMM.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod