Uhoh - I let the magic smoke(s) out....
History.... got machine (jacks to open) and one original display not working, and one p2/p4 digit locked on. Rottendog replacement mpu, Gulf pinball PS. Get the locked digits going and got a replacement display from a pinsider, which initially worked ok. Went to keep shopping and the new display craps out, figure it was just its time, etc. - disconnect and keep going. Then, all displays out, gulf pinball display section smoked, no schematics available, not paying $80 for another. It was blowing fuse F3 as well.
Go for the LISY design and the new PS/displays - had to repin a couple of the display harness connectors, visible sparking on the input voltage pin on 2x displays, so repinned both of those. Working fine up until a couple days ago, turned it on and display is incorrect on the credit display and other displays are really dim/off. It had blown F3 again.
Disconnected all displays and PS, tested input voltage for displays 60vac ok, hooked up PS, test voltages, all ok. (+5 is 4.9 where it was 5.1 when I first installed PS, but likely not important). Reconnected only credit display, still has bad info on display but lit. (power off between all connect/disconnect of course) - I did do the 10ohm mod for the displays on the PS when I built it (I ordered enough parts to build 10 boards, still have 4-5 to build up) Hooked up the p1 display and smoked what I think is the power regulator, and the 10 ohm current limited resistor blew as well, and F3 blew again as well.
I know it's never the transformer.... but do you think it could be the transformer? It doesn't blow F3 without anything hooked up to it, didn't blow it without the displays connected, but did blow (see pictures) when I hooked up the display. There was a big spark at the connector similar to what I noticed when the connector needed to be repinned.
I do have one spare display board that I can move the LED digits over to but I'd like to nail this down if I can before hand so I don't just blow them all up. I did turn up the brightness on all the displays as they were too dim - possibly the current just isn't enough to run all the displays so caused an undue load?
Any other thoughts?20210812_101353 (resized).jpg20210812_101417 (resized).jpg20210812_101427 (resized).jpg