Cherry Master Boards with Coin Jam Error that won't clear

[markhart]

I picked up a few Cherry Master boards that appear to be very clean and low mileage.  All three have a COIN JAM error that I cannot get to reset.  Years ago I had this same problem and I corrected it with a chip swap, but I cannot remember which chip it was.  Other boards work great in the cabinet so it is not a stuck coin switch or wiring problem.  Any help would be appreciated. Thanks.
 

[stayouttadabunker]

Now this is only a guess...
I'll betcha you might of changed out the ram chip perhaps?
That could of cleared and reset it possibly?
There are of course several versions of the cherrymaster board...
which one are you thinking of?

[channelmaniac]

Hmmm....

Stuck switch, bad switch, improperly wired switch (there's a Normally Closed switch contact that should NOT be used), bad wiring harness, or board problem...

Put a voltmeter on the coin switch contacts and see if they are sitting at 5 volt. They should be at 5v and drop to 0v when the switch is held down. If the contact measures 0v then you either have a short in the harness/switch, or you have a bad board.

Follow the traces back from the edge connector, check any resistor packs that tie the lines high, and follow the traces back from there to see which chip it goes to. Replace that chip. The chip in use depends on the board. There are a lot of different ways to interface switches to the board.

RJ

[ROCKET]

I picked up a few Cherry Master boards that appear to be very clean and low mileage.  All three have a COIN JAM error that I cannot get to reset.  Years ago I had this same problem and I corrected it with a chip swap, but I cannot remember which chip it was.  Other boards work great in the cabinet so it is not a stuck coin switch or wiring problem.  Any help would be appreciated. Thanks.
 

IF YOU GAVE MORE INFO ?
like the actual game board you have this problem with .I can possibly help you?

is it a standard cherry master board or a CADILLIAC  JACK  board ?

does it have a 3.6 volt battery on it or 5.5 volt on it ?

just pulling the game chip for 10 minutes may solve the problem -dont forget the notch in chip to line back up .

some caddilac jack boards you actually have to cut one lead off the battery for a reset .

 others that have a dead 5.5 volt mini batt. that dont have enough juice give crazy problems 

as i said more info would help ??

[markhart]

I found another Dyna Cherry Master board that was DOA and swapped the 3 longest chips that are end to end on the battery end of the board, and the coin jam message went away and board is working good again.   Thanks.

[channelmaniac]

Probably an 8255 I/O chip. You really should only need to replace one of them.