checkpoint DMD issue

starfighter2

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Sep 22, 2009
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Derry, New Hampshire
I have a fully working checkpoint pinball with one exception. the DMD does not display anything.

I first started off with the a power board issue, where the DMD would display but the game would reset. found that a two connectors where burnt. I changed that and 2 capacitors that looked bad. So I decided to just get a rotten dog replacement power board as I had seen alot of people have this issue. After that the DMD does not display anything. Ibeleive that all the fuses are ok, and the power to the dmd is ok according to the spec. I looked at the DMD board and there is nothing burnt that I can see? is there something else I can look at or is this thing shot?

New to pin repair so Thanks for any ideas you may have.
 
Measure voltages at the test points on the power supply board to be sure they are all present and within tolerance. Then carefully measure those same voltages at the actual DMD board power connector to be certain the voltages are getting there.

Also, be sure the ribbon cable is connected properly at the display board and the cpu board. It is possible to connect that ribbon cable backwards so check the cable to be certain it's connected properly (pin 1 to pin 1, etc).
 
So I had a little time to look at this. It appears that the voltage on my old board and the new rotten dog board are not correct. Also, a .5 amp fuse on either boards will blow right away. Anyone know where this fuse connects to? My felling is there is a short somwhere down the line of the connector to tzhe power board
 
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