Recommended Gottlieb System 80 Ground Mods (Haunted House – Part 9)

Now that I’ve got Haunted House running, it’s time to bulletproof the game – ideally you’d probably want to do the ground mods from the very beginning because in some cases, you might not be able to get the game working otherwise, but in this case, I managed to get the game to boot and appear to play well, so now we’re doing the required ground modifications to make the game more stable and reliable.

What’s actually involved in that?

It’s pretty simple. Gottlieb used single-sided edge connectors (unlike Trifucon which has contacts on multiple sides) for most of their connections. Over time, these connectors tended to fail, either by the contact surface becoming oxidized, or the blades becoming fatigued and not making good contact. Since ground is so important, without a solid contact, the game can behave in a variety of different and unpredictable ways, from random reboots, to intermittent issues with everything from lights to sound to coil firing. The general rule with Gottlieb games is if you’re having a weird problem that isn’t consistently repeatable, there’s a good chance it’s related to the powertrain. The most obvious culprit in the power chain is going to be the ground/return lines.

In-a-nutshell, the ground mods involve running an extra ground wire to tie all the different board’s ground lines to a common ground, and tie the head and the cabinet ground lines together — the only exception is you keep the 45v solenoid ground line separate (this is to ensure that if there’s a coil short, it doesn’t send high voltage to the rest of the game’s more sensitive components). Each board has a different recommended spot where you should tap into the ground, often it’s near one leg of a capacitor (which should also be changed if they’re original). Use 18 gauge wire (preferably green colored) and tap into each board with one end in the designated spot, then crimp a spade terminal on the other end and tie all the boards to a single ground plane (usually the metal bracket that mounts the power supply in the upper left corner — be sure to sand the paint off the area so you can make contact (alternatively you can also solder directly to the bracket.

Once you have all the boards tied to a single plane, you want to tie that to the head and the cabinet, by running wires from the power supply bracket to the metal frame in the head, and then one down into the cabinet to the transformer board, where you’ll find a ground backplane you solder to (on System 80B games, you’ll also want to take all the ground wires that terminate on the transformer board and tie them together, preferably eliminating the molex connectors they used which cause problems).

Click at the top of each image below for larger versions:

Pinball Feature: Custom Side Art Blades

This is a neat way to add extra art and visual appeal to your pinball machine using what are called side art blades. This is an area where many third party artists & entrepreneurs are finding clever and creative ways to mod pinball machines to increase their value and appeal. I talk about this and show you some examples.

Before
after

Recommended mods to Bally-18/35 and Stern solenoid driver boards

In today’s episode, I go over some standard, recommended modifications to the Bally-35 series solenoid driver board. There are over 60 popular pinball games that use this hardware setup and these quick modifications will help make the game run better and more-reliably. They involve adding three jumpers to the board. Whenever I have a chance to work on one of these boards, I do these mods.

Here are some front and back pictures of both Bally and Stern Solenoid driver boards. The black wires are the mods. The other colored wires are done by operators having to do with the coil lockout relay.

Bally Solenoid Driver board
Stern Solenoid Driver Board

The New P-cubed P-ROC-based prototype pinball demo’d at TPF

One of the coolest things to show up in the community in years is the P-ROC system, a custom boardset that allows interfacing a computer to traditional pinball games or the creation of entirely new games. At TPF 2012, developer Gerry Stellenberg shows off his new prototype game system called P3 (p-cubed) which incorporates a number of unique and innovative features.

Check out this exclusive video where I talk one-on-one with the principal developer as he shows off the groups’ creation: