Bally Solved The Addams Family (Bally, 1992) problem

[paul]

I'm looking for advice on how to repair my pinball...
I have a ground short in Row 5 in the switch matrix
disabling 8 switches thus not allowing play

1991 Addams Family Pinball

 

[pinballdaveh]

The manual shows the switch matrix row 5 info as white -green, j208-5 , and u19-11. This info means that a white-green wire will be common to all the switches in that row and end up at the cpu board jack plug j208 pin 5. J208 is on the cpu board, 1 row of jacks above the bottom row, the last jack on the right. Set the machine for switch test and unplug the plug to j208. If the row short goes away the problem is in the playfield, if the problem doesn't go away the problem is on the cpu board. If its a cpu problem, turn off and unplug machine, unplug all cpu jacks, and remove the cpu board. Inspect the cpu board for any corrosion near j208 and u19. Remove batteries from cpu, un-solder and remove u19. There might be a diode in between j208 pin 5 and u19 pin 11. This can be found by following the trace on the back side of the board. When found test diode for a short, replace if shorted. Solder in a ic socket and install a new u19. U19 is a lm339 quad comparator available from marco. Be careful the ic dot or notch is installed in the correct direction. Re-install batteries, re-install cpu board, and test.

 

[paul]

THANKS

Thank you for the direction,, I did find some corrosion on U19. Cleaned it up and everything is back to normal. Thanks, Paul