Bally Mastercom 250 troubleshooting

[Yoeddy1]

I’ll tell ya, these damned things drive me crazy.  So one of my Mastercom 250s was resetting.  I pulled the small thin eprom out of the socket on the board and also my custom chip out of the socket.  I let them sit on my counter for a couple of hours and I connected up a different VFD and card reader out of my machine.  Guess what?  It worked!  I took the Mastercom 250 and all of the same cables and power supply back to my slot machine, and connected them up to my card reader and VFD in the machine.  The Mastercom just resets like it’s watchdogging.  Is something hung up in the firmware?  I’ll pull the chips again and then try again on the components in the machine. 

Do these Mastercoms require pulling the chips to do a reset?

Thanks,
Jason

[Stayouttadabunker]

It's a good thing you have a spare Mastercom board, chips, and power supply.
An easy thing to check is plug the good power supply onto this problem board.

If it resets, then you know the problem lies with the Mastercom circuit board.

If it doesn't, then you know it's the power supply.

[Yoeddy1]

These are really difficult to troubleshoot.  If a short goes through it, the surge must take everything out.  I ended up putting in a brand new VFD, card reader, and button pad, and it works perfectly again.  The MC250 was fine all along.

Thanks,
Jason