(Topic ID: 139035)

Bally Power Play - Display/MPU issue

By essmeier

8 years ago

Topic Stats


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#1 8 years ago

I'm an EM guy, but recently acquired a relatively clean and (at the time) working Bally Power play at a good price. Since I got it home and reassembled it, some issues have popped up and I'm largely unfamiliar with troubleshooting these early solid state machines.

Here's what's up:

When I first power the machine up from a cold, unplugged state, it appears to work normally. The LED on the MPU flashes 7 times as it should and the machine will start a game. Running through test cycles from the button on the coin door suggests that everything is as it should be.

After about two minutes, regardless of what I'm doing, all displays go dark, and the machine stops responding. General illumination remains on. If I immediately turn off the power switch and turn it back on again, the LED on the MPU lights and stays lit. If I unplug the machine and come back in 10 minutes or so, it passes self-test and starts up normally...only to shut down again in about two minutes. I haven't been able to play a complete game yet.


All boards are original, including the MPU. Battery is still attached and not leaking, but parts to replace that with an off-the-board battery should be here in a day or two. There is no visible corrosion on the board.

Fuses are all good, and there is no connector burn at the rectifier board.

Not even sure where to begin here. Flaky MPU? Power supply issue?

As it happens, I'm in possession of a Bally Kiss machine that I'm restoring for a friend of mine. That machine is going to require complete replacements of all boards, so I should be in a position soon to swap boards and/or the power supply out with new ones on Power Play for testing purposes. Still, I'd like some ideas as to where I should be looking first.

Suggestions are welcome.


#2 8 years ago

Connectors come first. Check under the headers on the power supply board, solenoid driver/regulator board (at least the .100 size on the right) and at least J4 on MPU. Mandatory on this vintage Bally.

Also carefully reseat the socketed chips.

#3 8 years ago

I did all of that, and for the time being, it seems to be working. There are a few other minor quirks, but those are things I understand - coils, switches, etc. I'll get that battery issue fixed, get some new rubber and bulbs in it and see how things go.

I'll get back to this thread if anything else goes wrong.



#4 8 years ago

I redid all the connectors on the rectifier board and it solved the same problem for me. Hope that was it. I have a Power Play and a KISS and they were the 1st pins I bought back in the late 90s. PP is my one I've wanted since '78. It's a keeper...........

#5 8 years ago

Does your MPU have the dreaded brown sockets on the big chips and eproms? Those were notorious for causing strange MPU issues on some of the early boards. If all the sockets are black, thats good. If they're brown, get them replaced or install an alltek board. If your problem happens again, open it up while its failing and check the 5v at the mpu board. You will get a reset condition if the 5v drops too low or gets noisy. The LED being on solid means it did not have adequate 5v, or the MPU was unable to reset or start booting due to a board problem. Rick

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