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

Okay, thanks so far for the responses.

I haven't checked for a transistor under the playfield so I'll give that a shot. I'll re-check the fuse when I get home tonight and will update this thread, or tomorrow afternoon if I just get too frustrated and start drinking. Hah.

I'm just not hoping the problem isn't in the CPU.

I have the schematics and all that good stuff, so I'll be able to trace everything.

To be continued...

Thanks again with the advice so far.

And yes, haven't taken care of the ground mods yet. I know.... I need to do these as soon as possible.

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?

Another question folks, I'm guessing the new Ni-Wumpf driver board needs to be grounded, right?

Does the Ni-Wumpf driver board have the same numerical values on the pcv as the old driver board so I can just follow the grounding mod instructions on Clay's "System-80 Repair Guide"?

Just wrote to the dude from Ni-Wumpf asking him but wanted to ask you all as well. I'm at work so I can't look at the two boards to A/B them.

Thanks again.

Grounding mods (all of them) will begin tonight.

**PROBLEM SOLVED**

I modded and installed a pop-bumper driver board to replace the K-switch.

After wiring the cable through the extra available pin on the connector harness, powering this sucker on, WHOOM!, the up-kick works perfectly.

Replacing the stock coil with the A-4893 coil launches the ball with an intense velocity, making the game a lot faster.

So, all is good! A very happy table now lives in my house.

Thanks for all of the help everyone.

-Bob