Never owned one but the process is covered in detail in the TOP 5.1 and 5.2 DVD's by Clay. Doesn't appear too hard.

52 (resized).jpeg

Hi Superbee,

I did a fair bit of research before I did the ground mods on my Black Hole (which has the same boards as Haunted House). I tried to find the most unobtrusive attachment points on each of the boards for the ground wire. Most of these attachment points are on the components rather than on the boards themselves. I ran a single wire from the attachment point on each board to a common point on the inside of the head to tie the grounds together and also attached the ground wire from the bottom of the cabinet to this point. This way you do not have to worry about sanding back the cold plate of the power supply to use as the point to tie the grounds together.

Here are the attachment points on each board:

Power supply (left hand side): 20180214_222809 (resized).jpg

CPU (left hand side): 20180214_222017 (resized).jpg

Driver board (upper right):20180214_222031 (resized).jpg

Sound board (upper right):20180214_222134 (resized).jpg

Speech board (Haunted House doesn't have this board):20180214_222155 (resized).jpg

Tying the grounds together at a common point in the bottom of the head:20180214_222231 (resized).jpg

And in the above picture, move that factory green ground wire from the lock assembly to where all those added ground wires are mounted.

Personally I like to have the central ground Closer to the boards. Because if you have to remove one of those boards with the added ground wire, the way it’s pictured above kind of makes it a pain in the ass

Well you do need to solder the ground wire directly to the boards. You don’t have to do all the ones that are pictured above. The main ones are the power supply, CPU board, driver board. Those are mandatory. The soundboard and the light chaser boards aren’t really as important. That is, if they have a connector/ground issue on them, the game is it going to burn up a coil and start on fire. The only thing that happens there is maybe your sound doesn’t work or the back box chaser lights don’t work. Which is nothing compared to smoking a coil and burning up transistors

Maybe someone will do the same (Illustrated) of the earlier system80 boards. I know you have them on Clays repair site and pinwiki but, it is a very clarifying way of how it's done a little differently

Flippers.com has an illustrated grounding guide too.

Added a wire coming up from the cabinet transformer panel ground strip to the bundle of new ground wires in the head. Did a bunch of System 80 ground mods this year, for games that have run ok for 25+ years without the mods.

the easiest way is to look it this youtube film #227 Gottlieb HAUNTED HOUSE pinball machine with 3 levels of play! TNT Amusements

I've seen TNT's video but I like the idea of grounding each board which they do not.

What if you have a pascal all-in-one board are any mods necessary?

no you have to do nothing be sure your connectors are 100% ok

it's your decision how you wanna do it

I personally do not suggest the TNT ground mod by themselves. It’s a very minimalistic approach and frankly I just don’t think it’s enough. In adding grounds to three boards literally takes 10 minutes at most. I don’t really see the downside. Doing what Todd suggests, personally, I think is in adequate

Another way to implement the Ground Mod to your Haunted House. These are taken from my own Haunted House. The brown wire is running to the metal groundstrip at the bottom of the cabinet. I would also recommend to double up the +5V and GND connections between driverboard and CPU board.

I do NOT recommend to use the power supply's heatsink as a Ground Plane as you are creating a potential short with the +12V (at the housing of the metal transistor mounted on the heatsink). The heatsink should stay as designed: floating.

WP_20180214_18_29_39_Pro (resized).jpg

WP_20180214_18_29_54_Pro (resized).jpg

I think you will be better off soldering to the back of the boards, plus I think it looks better also.

i have plenty off Gottlieb pinballs ant no problem whit tnt ground mods l

The TNT ground mod, by itself, is totally inadequate. It relies on using connectors which basically already failed to do the job once. It would be like crashing your car into a ravine, and then crashing another one into the ravine again, like that’s going to help.

The whole reason the ground mods are required is because this style of connectors don’t fare well with time and have basically failed. All you’re doing with the TNT mod is using the same unreliable connectors. You’re just doubling them up. That is not a way to solve this problem. Fool me once my fault. Fool me twice, you’re an idiot

I just added another wire connecting the factory green ground wire at the lock assembly down to common point the bottom of the head.

That's true, it does take a bit more maneuvering if you have to remove a board when they are wired this way.

Yes, do this in addition to the ground mods I posted above.

This is the first of a few things that need to be done.

http://www.google.com/url?q=http%3A%2F%2Farcarc.xmission.com%2FPinball%2FPDF%2520Pinball%2520Misc%2FBlack-Hole%2520and%2520Haunted-House%2520Repair%2520Guide.pdf&sa=D&sntz=1&usg=AFQjCNFPMdoxybzrJtcWJVi7dQ8y3y290g

Here's a good read.

just picked up a Hollywood heat and a monte carlo, guess I got to get busy on some ground wires. uggghhh!