Greetings people. I am having a problem with a dual channel Keithley 2612 SourceMeter. Moments after I power the unit on, I am greeted with an error : "5046 - SMU B: SMU too hot". Now, I can see that this error is considered SERIOUS (
https://www.manualslib.com/manual/1228418/Keithley-2600a-Series.html?page=645). I have disassembled the device and I have swapped the SMU cards, I am then greeted with "5046 - SMU A: SMU too hot". At least I know that the problem is somewhere on that particular SMU board and not on the motherboard.
Has anyone any similar experience with recovering from such error code? I foolishly thought that I would locate some sort of thermistor or temperature sensor on-board but NAH, that thing is pretty crowded and complex for my experience.
I am willing to post a step-by-step tear down and repair if I can have some feedback on where the F*** to look for the temperature detection/sensing. I appreciate any input.
*EDIT* I am also linking the awesome post that helped me with the teardown:
https://www.eevblog.com/forum/metrology/keythley-2612-teardown-and-repair/ which unfortunately does not have information for my problem. I am sure that someone more experienced might just spot the appropriate subcircuit from the high-res images.
Additionally, I attach an IR image which shows (under no load) that the thermal profiles are quite similar for both PCBs, but the error occurs.