I'm following this thread because I had some STTNG flasher problems that I didn't understand. They would work intermittently and the fuse was not blown, and I had <1 volt on the 20 V line. As I was about to replace the bridge rectifier, I realized the fuse was blown. I replaced it, and everything has worked since. But clearly, a blown fuse was not my only problem.

F111 fuses half of the AC input from the transformer.

To measure the AC voltage, measure between the following:

• J102-3 or J102-4 (or one of the F111 fuse clips)
• J102-1 or J102-2

Reference this potion of the WPC Power Driver Board schematic. (Not much to the circuit!)

f111_(resized).png

Correct. When I put two bullet points, I meant measure from one to the other, not from each to ground.

Set it to AC 20. You're expecting to measure about 20 volts.