Quoted from sturner:So I'm fairly confused. Removing J210 and everything works fine I'm told would make this an MPU issue. But odds of both boards (including a new Rottendog board) having the same issue seems slim. I guess at worst I'm trying to figure out where the likely culprit lies. I'm not sure I could handle board work yet but at least knowing which one has the issue would be great. Or if something else could be causing the issue on the machine. Any help would be much appreciated!
I don't think that's a fully true statement, it's making assumptions that one of U18, U19, U20 are blown, and that there are no other shorts downstream on the switch matrix. But the way one usually blows U18, U19, U20 is that there is a short on the switch matrix to either the lamp, GI, or solenoid power.
So you really need to find the short in the switch matrix on the playfield, then replace the failed U18, U19, or U20 (most probable), then replace the fuse.
The only thing you did was put in a good MPU, played a game, which when the ball hit the right spot, shorted a switch to some other power source, and you blew another U20 or a second MPU. Thus the crux of the statement is right about J210, if the fuse blows immediately with J210 plugged in, but doesn't blow with it removed, then the MPU has a bad chip. BUT, you never solved why the MPU has a bad chip to begin with.... Which is why replacing the board only got you a second bad board.
Rancho Cucamonga, CA
Vancouver, BC
