It wasn’t the hybrid! In this update, we repair the HP 3438A ohms range thanks to the helpful comments from our viewer community.
My HP 3438A Service Manual Scan: https://archive.org/details/hp-3438-a-digital-multimeter-operating-and-service-manual/mode/2up
HP 3478A Multislope II DVM repair: https://youtu.be/p1r5ze8Xcfw
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00:00 Recap of the previous episode
01:12 Commenters think the hybrid may not be dead
02:06 Ohms measurement principle
04:09 Our symptoms do not match a hybrid failure
04:32 Possible alternate failure scenarios
07:32 Re-testing the front switches
08:03 Front/rear switch seems to be the culprit!
09:30 Repairing the corroded front/rear switch
11:13 Calibration
12:45 The ohms range works again!