Author Topic: Keithley 2000 repair  (Read 729 times)

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Offline mauritTopic starter

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Keithley 2000 repair
« on: March 02, 2023, 06:04:48 pm »
Good morning everyone,
I have recovered this Keithley 2000 of the year 2006.
The voltages are OK but Q115 (LM339) is cooked
The PCB is also damaged along with some traces.
Which procedure do you recommend ?
I attach the photo of the damaged part.

Thanks
 

Offline Kleinstein

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Re: Keithley 2000 repair
« Reply #1 on: March 02, 2023, 06:18:24 pm »
Chances are there is more damage than the visibly burned part.  This are especially JFETs (SOT23) controled by that comparator, but also the LTC1050 and another OP amp at the input.

The good thing is that the LM339 is readily available and the chip itself not critical with leakage or fast signals.
The burned PCB remains can be somewhat conductive. So one would need to remove it and maybe patch the hole to put in a new part with more flying lead connections. Alternatively one may just isolate the area and have the replacement in dead bug style.

It may be worth forst checking the suspect parts near by, as one may want wires directly to these parts.
 

Offline mauritTopic starter

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Re: Keithley 2000 repair
« Reply #2 on: March 03, 2023, 11:46:30 am »
Hi Kleinstein,
thanks a lot for your valuable advice.
I will do what you say !

Maurizio
 


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