Author Topic: Keithley 2100: How does one identify a burnt SMD resistor without service manual  (Read 18371 times)

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Offline bendzo

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Hi,
thank you! It's actually mostly your merit  :-+ , thanks again Kleinstein!
I bought this faulty meter to look inside and learn something by hands-on experience, and it was a big success!
And as a bonus meter seems to work fine after repair, I will try to roughly test it's precision, but I don't really have any suitable references at this moment.

There is only one last annoying/suspicious thing, meter has a big(?) offset from zero, it's reading 0.18mV with leads shorted, the same for amps, 0.18mA for 1A and 3A range, 0.035mA for lower amps ranges (gain 0.2?), is it a fault? Is there any way how to "fix" this offset (beside "NULL" button of course ;) ) ?
Thank you!
 

Online Kleinstein

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The meter likely has a software function to compensate for input amplifier offset. So a kind of null function, but more permanent.

If this function was used by the previous owner with the bad higher bias current this would likely also result in extra offset.

So checking the offset calibration should be the first step.
 

Offline Chris56000

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Hi!

No schematics included unfortunately, but the Keithley is the same as the Picotest/Array M3500A and a Service Manual with at (least!) A Full Component-Level Board Parts List (down to individual Rs and Cs!) with PCB layout drawings is provided so you can check what you've fitted is here:-

https://www.picotest.com/downloads/M3500/M3500A%20Service%20Manual%2020111031.pdf

Chris Williams
It's an enigma that's what it is!! This thing's not fixed because it doesn't want to be fixed!!
 
The following users thanked this post: coromonadalix, technogreek

Offline FlyingHacker

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Thanks! This is worth raising this thread from the dead. Very helpful. Thank you.
--73
 


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