Trying to help a friend get his Bally Playboy up and running again. The game presented in a non working state, 5 LED flashes. Tested all voltage test points on the MPU and all were well within range. Removed the MPU and installed an Alltek, powered on and game booted and played. Left my friend to enjoy playing his game and took the MPU home to investigate.
The history I received was that it had been working for quite a while and then the pf switches didn't register and the sound went funny, not playing all tunes. Eventually it wouldn't boot and that was how I found it. The battery had been removed long ago and replaced with a lithium coin cell. The board had some sockets replaced previous on the memory IC's and the CPU. The CPU itself has no markings whatsoever, wiped clean or sanded off. I replaced the sockets for the EPROMs and the CPU as these were still the originals. Also removed U12 (555), installed a socket and put in new ICs at U10, 11 and 12. Both PIA's and the 555. Installed back into the game and the board boots, start a game, beauty. Well not so fast, not one switch matrix switch on the playfield registers. Connectors J2 and J4 are both clean and pins soldered in place.
I've checked over the board thoroughly and checked continuity from each pin of J2 to U10 and from J10 to the CPU at U9, along with component values, all test ok.
I could replace the PIA at U10 and test, but my gut feel is something else is wrong. The sounds isn't right either and that is controlled by the other PIA at U11. However, the pop bumpers, flippers, slingshots and ball trough kickout work fine at power on/ball on the playfield. With the voltages and resistance to ground connections checking out, I'm at a loss to workout whatelse is common?
Is it possible that the CPU chip is the wrong type? But the board now boots ok and so I'm told the game was working. Any ideas? Hoping someone can help or seen this problem before.
Forgot to mention...when in switch test it reports a flashing zero indicating no switches are closed, which isn't surprising considering none of them register during game play.