All,

Working on a game for a friend - the downside is that the game isn't in my possession and therefore I need to make the most out of each time I go over there...

I got the game running and playing - it has a new rottendog MPU. The only remaining problems are that one of the cooling towers pop bumper doesn't fire (switch works and scores but no bounce) and the right drop target doesn't reset.

My plan based on research (looking for recommendations or confirmation)-

Note that I've already confirmed all fuses and fuse holders are correct/stable.

1. I will start by testing the transistors on the new MPU to make sure they aren't shorted. I am hoping this isn't the case since the board is brand new... but such is life.

2. Next would be a power test across the two applicable coils.

3. Next would be to cut diode end and test it.

I'm wondering - if the MPU transistors are shorted should I just replace the coils? With a brand new MPU having a blown transistor can I assume something in the coil likely is bad assuming no other wiring shorts are present?

Should I be doing anything to the PPB for this repair other than reheating solder joints?

Thanks in advance for advice.

When you say "ground the trigger wire at the driver" what exactly do you mean?

Excellent - thank you for the clarification - I've tracked down the respective transistors to test and will follow your recommendations to isolate the issue!

Note that I meant I've tracked down the coil numbers - I realize your instructions were to ground the coil wire on the CPUboardand not the transistor itself.