Voltlog #34 - Fluke 77 Teardown & Repair, Varistor Replacement

In this video I’m opening the Fluke 77 I scored at a recent auction to show and repair a small issue it has. One of the spark gaps used in the input protection circuit had suffered damage probably while protecting the rest of the circuit when a HV signal was applied to it’s input. For the repair the sparkgap was very hard to find so I replaced it with an MOV. For reference, future Fluke 70 series did switch to MOV protection instead of the sparkgaps so it should be fine and continue to function as intended.

The original spark gap part number is Fluke 655134 1500V surge protector.
The replacement MOV part number is Panasonic ERZV10D911 specs 910V 1mA

Fluke 77 Manual:
http://voltlog.com/y/9tyye

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