On the big board the resistance checks on OB and OA showed over-limit.. maybe that was a bit weird because my meter can display mega-ohms. I do not dare try another voltage tests, but I remember G was 0V and B+ was also good. OA and OB were about 110V. Everything seemed to work beautifully initially for at least 5 minutes and I was already trying to listen to the differences when the troubles started. The only thing I can see that I don't feel very confident is how one of the leds on the large board were soldered, but I checked it with the meter and it appears to be fine.
I put some images on dropbox. Unfortunately the one where I wanted to take a photo of the glowing leg is not sharp
. I did an emergency shutdown to prevent more damage before I could check.
Should I picture a specific area? Note that my crack works perfectly well with just the small board + the ceramic resistors.
https://www.dropbox.com/sh/v1dabyei4cq7yq4/AACSl2aKISM9dpu1iTHpVWASa?dl=0There is a movie showing a second test without smoke where the two leds on the bottom glow very bright while the six others are dim. Initially they all light up the same. There's also the very unsharp image of the "glowing" I described, you can see the glowing spot above the leds between the TIP50 legs.
I'm not 100% my replacement tip50 is a correct replacement. It fits perfectly and is specced to 400V. Do I assume correctly all TIP50 models use the same pinout?
I read about 10 threads on this forum about similar problems, but I think I have a different one
. I'm happy to picture or measure anything you want.