Workin' on fixing up a JP that was sitting in our storage area for ages. The only power board we have is one that literally has a hole blown in it, so it had...problems. I've fixed the five volts up and running, but F7, the .5 ground fuse for the AC kept blowing. I replaced the four involved transistors, and an interesting thing happened. I plug it in, and there's a big spark on the right leg of the 15031, and the 5401 literally explodes. While amusing, I've actually seen this happen on a WPC display board before, but could never fix it. Clearly, too much current is running into the 5401, but why? What causes it? I replaced the zener diode, but that doesn't seem to be it.

Yeah. :/ I did take the diode from a -00 board, 'cause I don't have a 1n5228 on hand. So it still might be it. Is there a common zener I could stick in there as a replacement?

Oh, or is it maybe the "downstream" diode, D11, the 100v? I didn't try that yet...

Actually I've repaired about 15 WPC display boards, but not any data east. And I have most of the parts, we just don't have that one zener. The reason I'd rather fudge it is that it takes like 2 weeks for parts to get ordered and arrive around here, and I've got the free time now.