Could use a little advice from any WhiteStar experts. Helping a buddy who apparently shorted the switch matrix to something (he said the coin door was open so shouldn't have been the coil drive) and now has some problems I've isolated to the board (I think) by removing the playfield connections to the board. Using the diode and jumper test method I've figured out I have one completely dead column (the transistor for that column is toast) but two other columns behave oddly no matter which row is connected. On both simulating any switch in that row causes every switch in the ROW to cycle through when one is activated, stopping with a different switch than what was activated. For instance if I simulate switch at column 3 row 5 it will show every switch in that row fire in order and then stop and 3-7. Since this behavior tracks with the columns I believe I have three bad drive transistors but could it actually be the chip(s) on the return side causing this instead / too? I read all the how to troubleshoot switch matrix issue articles but it doesn't cover this particular "machine-gunning" behavior.