Tech: WPC Dot Matrix Controller Board Problems

kastawaykid

New member
Joined
Nov 10, 2004
Messages
127
Reaction score
0
Location
Wisconsin
Hi,

I hope some one can help me. I have a WPC Dot Matrix Controller Board
(A-14039) that I am having problems with. When first powered up, the
DMD has garbage all over it and is not blank like when using a good
Controller board. When the High scores are shown, the display looks
good and shows all the correct characters with the bad board, just
like the good board. When it goes into the "Drugs screen", I can see
the words but have garbage characters on all over the screen. Someone
in the past has worked on the board and the RAM has been replaced with
a socket/chip (I also checked with good RAM from the other board). I
know all of the cables are good (and oriented properly) and the display is also good, so I have it pinpointed down to the components on the Controller board. Has anyone experianced this before with a Controller board?

Here is a video of the issue:
http://www.youtube.com/user/kastawaykid?feature=mhsn#p/a/u/1/2YRcQGS12qw

Please let me know,
Kid
 
I had a problem once with garbage on the display but it turn out to be a bad ribbon cable.Have you tried reseating the ribbon cable?
 
I have tried 3 sets of ribbon cables (2 brand new sets from GPE) and I still get the same thing. The orientation has been checked (many times), because I have had the board in and out of the machine (I have also check continuity of the cables to the pins on the board). I have eliminated everything down to the level of it knowing that it is a component issue on the controller board.

Thanks,
Kid
 
Hi,

I hope some one can help me. I have a WPC Dot Matrix Controller Board
(A-14039) that I am having problems with. When first powered up, the
DMD has garbage all over it and is not blank like when using a good
Controller board. When the High scores are shown, the display looks
good and shows all the correct characters with the bad board, just
like the good board. When it goes into the "Drugs screen", I can see
the words but have garbage characters on all over the screen. Someone
in the past has worked on the board and the RAM has been replaced with
a socket/chip (I also checked with good RAM from the other board). I
know all of the cables are good (and oriented properly) and the display is also good, so I have it pinpointed down to the components on the Controller board. Has anyone experianced this before with a Controller board?

Here is a video of the issue:
http://www.youtube.com/user/kastawaykid?feature=mhsn#p/a/u/1/2YRcQGS12qw

Please let me know,
Kid

Looks like a Party Zone!
Looks like your RAM chip is bad. 6264 (* I believe) Your DMD controller isn't paging memory correctly. If you can get it into test mode run the Display test. It will test the page banking... More than likely it will fail.
 
Finally got time today to sit down and figure out what was wrong with this.

One of the Quad Flip Flops (74LS175) was bad. Replaced it, and all is good now.

Thanks to all that posted,

Kid
 
Back
Top Bottom