Ms. Pac Man Game Counter and Screen

BlindMolly

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I have been fighting this Ms Pac Man machine forever. The problem is that when I turn it on, the screen has lots of characters flashing on and off, all scrambled up and the counter on the inside of the coin door keeps clicking up games. Sometimes I can get it to stop and the start screen starts, but I am not sure what I am doing to get it to clear up. If I turn it off, wait a bit and turn it back on, it usually happens again.

I have not replaced the board, though I did replace all of the internal wiring, including the power supply. Does anyone have any clues on what I'm doing wrong here?

Thanks for any help.
 
If the counter is clicking,it usually means that the machine is being coined up.check the coin switches for a stuck switch...failing that,try disconnecting them to eliminate them from the equation....
 
Replace your Z80 with a known good one and try it again, after making sure that your edge connector is fully seated on the board.
 
If the counter is clicking,it usually means that the machine is being coined up.check the coin switches for a stuck switch...failing that,try disconnecting them to eliminate them from the equation....

No... on most games the counter is triggered by software, not directly by the coin switch... if the counter's clicking randomly, the CPU's just running random garbage code.
 
Great idea on the coin mechs. I'll try that. What is a Z80? Newbie here.
Bally%20Ms%20Pac%20Man%20PCB.jpg


For Ms. PacMan, the Z80 is on the daughter board. That's the board on the right with the ribbon cable going to it... where that ribbon plugs into the smaller board, the chip right below it (the long one) is the Z80.
 
And, on Ms. Pac-Man, you can eliminate the daughter board for testing by simply plugging a Z80 into the socket on the main board instead of the ribbon cable. The board will then play regular Pac-Man with some of the wrong graphics - but it'll work. Sometimes the ribbon cable gets flakey and causes weird problems.

-Ian
 
At minimum you have a board issue. Make sure everything on the board is seated fully, might just be a bad connection. Suspect roms or ribbon cable.
 
Thanks very much. I don't have a daughter board. Attached is a picture of what I have. I am having some success with moving the two small boards attached to the main board around, but I can't get anything to stay consistently. Any ideas?
 

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Thanks very much. I don't have a daughter board. Attached is a picture of what I have. I am having some success with moving the two small boards attached to the main board around, but I can't get anything to stay consistently. Any ideas?

Ahhhh.... hacked board? The Z80 is under he daughter board on the upper right there. Anywho, if you're having some luck moving the boards a little, might be time for new sockets or at least some reflowing on the pins for the sockets. There are probably a few wires on the back of the board as well, might check them to make sure they haven't gotten knocked loose or developed any cold solder joints.

Make sure your chips are seated properly too. Just give them a good puch down to make sure they're snug in the socket.
 
great. Thanks. So is this a hacked board? Should I consider getting one that is not?

Check the jumper wires on the back (needed for the hack). If any of those are torn up, it'd explain why your board isn't working.

Most kids don't care what hacks have been done (within reason), so you could just get a 6-1 and ignore the hackedness...
 
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