OP

Quoted from bklossner:

Hi folks,
Here we have a Haunted House machine with a non-working vertical upkick on the lower playfield.
I've replaced the stock coil with a new A-4893 coil (purchased from Marco), attached a new 1N4004 diode AND installed a new Ni-Wumpf driver board with no luck.
When the ball enters the hole for the upkick the machine makes the noise registering the ball is in there, updates the score on the display but the coil is not firing. Instead it just sits there while the sound loops and the score is constantly updated.
New coil, new diode, even a new driver board isn't fixing this.
Wiring problem? CPU problem? I'm not sure right now.
Guess I'm gonna take some things apart tonight but I wanted to ask you all as well.
Thanks.
-Bob

OP

Quoted from bklossner:

Okay, I've checked the transistor below the lower playfield. Ran a DMM through it (with the machine turned off) and the values were bouncing all around. Most of the time I wouldn't get a reading and then the other times it would fluctuate between 0.4V to 1V.
I'm guessing the wild fluctuation means this sucker needs to be replaced. Am I correct?