Was in the middle of a game recently playing TOM which has been reliable in 3 years of ownership. Everything working great and then suddenly the game turned completely off. It was as if someone had unplugged it not the annoying classic flipper reset at all. Game went completely off and didn't turn back on. I literally thought the dog might have been wondering past and accidentally bumped the power chord. Checked chord was in outlet tight and back of game, not loose or out. Turned out the inline fuse under the playfield had blown, I have no idea why.
lt will turn on, all lights, displays etc work and start a game but switches row 5 and column 2 switches will not work. So no in or outlanes and any switches with the row and columns mentioned. However don't get ground short error messages when game is turned on. If I disconnect one connector on the opto 7 board under the playfield almost all of the switches on row five work but not the any in or outlanes which is also a part of column 2.
I have checked all the fuses pulling them out an using a dmm, relevant connectors for good connection and replaced ULN 2803 on the CPU. Used a DMM and checked diodes on switches and have been over and over looking for any lose, cut, or misplaced wires or solder that got somewhere causing a short. Had done no work on the game prior to this all happening where I might have screwed up a repair.
I wonder if somehow a chip on the 7 opto board and another chip or component on either the CPU or driver board died. Also noticed last night in switch edges test the popper soldenoid is activing any time I push on or both flipper buttons. I've read lots or artciles recently about shorts, switches rows and matrixes. Still have mad NO progress at all.
Would please apreciate suggestions on what else to try.
Hagerstown, MD
