Update: see post #8 . I swapped in a working solenoid driver board and the displays are working so the issue is on the SDB. Just not sure what that issue is.

My displays were working OK before this started other than they would all constantly flicker but you could still read the scores.

I noticed that display for Player 2 was illegible so I grabbed a spare display (unknown if working at the time) and swapped it in (while the game was still on) and it worked. So I then powered off the game to properly mount this new display into the game.

When I turned the game back on, to my surprise no displays at all were working. So I checked the wiring and everything seemed as it was before I swapped this display.

Following the troubleshooting steps from pinwiki and Steve Kulpa, I then checked F2 on the rectifier board and it tested good. Then the fuse on the Solenoid driver board, and it also tested good. In fact, all fuses everywhere are good.

I then measured TP2 on the Solenoid driver board and am only getting 2VDC and it should be 170VDC. According to the pinwiki this may be a problem with the regulator. However, I then swapped in a known working Solenoid Driver board and got the same results. But also when I fired the game up the new display that I swapped in CAUGHT ON FIRE! Well, part of it anyway (pic below). So I flip off the game immediately and swapped back in the original illegible display. When I fired the game up again, no fire this time, but still no displays are working. So now I have swapped back all boards and displays and starting from the beginning. I did notice that the fuse on the known working solenoid board that i swapped in blew when I had it in the Embryon. However, the fuse on the original board is good, I replaced it anyway but same results.

I measured TP2 on the Rectifier Board and am only getting 150VDC when it should be 230. Could this also be causing the issue of only reading 2VDC on the solenoid driver board at TP2?

I also swapped in a known working rectifier board into the game, and I am getting the same results.

What should I look at or try next?

Link to repair page. see "All displays are blank" section.
http://stevekulpa.net/pinball/bally_disp6r.htm

Pic of display part that caught fire when I fired the game up.
FullSizeRender (resized).jpg

Yes, TP4 is measuring 6VAC

If I understand what you are saying, it is measuring about the same.

Yeah, as soon as I unplugged the display with the game on i knew that was probably a bad idea. Lesson learned.

I tested the test points on the displays themselves and I have +5V but on the high voltage TP I am getting about 2V.

So the problem is I am not getting high voltage then? Does that start with the rectifier board? When I swapped in the know working rectifier board, the problem remained the same.

OK I am following most of that. I am not sure where E5+6 are though. I don't see any E's on the bridge rectifier board.

The voltages at R3 are maybe 10V higher than at TP2 (around 160VDC) but still nowhere near where it should be.

With J1+3 unplugged, I am getting the same voltage readings on the test points.

I am able to get a reading of 180VAC on one side of CR1. Hope that helps.

Quick update. The problem is on the Solenoid Driver Board.

I swapped in the known working Solenoid Driver Board again and the displays are working. I swapped it back in because I realized that when the display caught fire it blew the fuse on the board and I did not replace the fuse before testing it again.

So at least now I know that the problem is on the solenoid driver.

Fixed! I replaced the transistor (the one with the star shaped heat sink) and now everything is working!