I was just contacted by a pinside member about issues he is having with his Countdown pinball. To make life easier, and so others can contribute and/or learn from this issue, I'm posting the information here with my initial response.
Here is the problem.
I had a bad power board and was having an issue with my yellow target
reset coil not firing. After reading about other issues with bad grounds
and board problems, I bit the bullet and bought a Pascal Janin all in one
board. I bought this one mostly due to the game enhancements that he added
to it. At any rate I am still having issues with my reset coil not
working. After I installed the Pascal board, at game start the coil would
now lock and stay on, before it would not fire to reset targets. I tried
disconnecting the coil, and then the blue target reset coil locked on and
fried. I've gone back to Pascal to look for help, but he's pretty much
telling me it was something existing in my machine, and I don't doubt that.
He has tried to help me, but the electronics gets lost in translation.
I'm happy to help where I can.
There are two under playfield transistors on Countdown that drive the yellow and blue drop target bank reset coils.
There is a lamp driver transistor that serves as the predriver for each of them. Since you have installed a Pascal all in one board there should be no issue with the predrivers. I would first look at the under playfield 2n5875 transistors.
Clay's System 1 repair guide is your bible for now. It can be accessed here:
I think the link will take you to the solenoid section.
Also, here are pictures of where these two transistors are located on the underside of the playfield near top end of the playfield.