I'm helping a buddy repair his Williams Laser Ball.  He had purchased a Rottendog MPU 327 combo board, so I got it installed and booting up, but no displays.  Everything else worked fine but all displays are dead.  I was able to repair the original boards as well and the displays work just fine with the original boards, so it appears the displays not working is an MPU 327 issue.  Do you have any ideas on what the issue may be?  There was nothing obviously wrong with the board that I could see. Anyone have any schematics for this board?

tech bump

Yeah, I'm working on the original board set now and have it booting up, still trying to figure out why it won't save and boots in to audit mode with the original boards.

I'd like to get the Rottendog board working too as my buddy spent good money on it and it hasn't worked since day 1. I sent an email through the Rottendog website, but haven't heard back yet.

Thanks for the ideas. I put a remote battery pack on the game as the old battery hold was already cut off. Diode D17 tested as an open, so I think that is the cause since there is no voltage at TP7 when the game is off. I'll work on replacing the diode tonight.

Any ideas on the missing displays on the Rottendog board?

D17 was open and replacing it fixed the game and it boots up normal now for the original boards.

Still nothing on the Rottendog MPU display issue.