I have an F14 that for the life of me, I cannot figure out why it keeps blowing Q49 on the SDB. When it does, any switch on column 2, activates all of the switches. I have tested each switch individually and they work fine, when I replace the transistor. Each diode tests good, all are in the correct orientation.

The pin has had substantial work underneath the playfield previously... but I cannot find a cause for this. I can put it in switch test and they work all day long. Start playing a game and usually within a couple minutes, the game will reset and the transistor is blown again. I've tried to see if it is some other switch, but it never seems to happen under the same circumstances twice. I'm thinking the problem must be further upstream on the board.

Has anyone run into this?

You were absolutely correct!! Thank you very much, that one has been driving me insane!!