Gottlieb Ground Cures by series

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Gottlieb Ground Cures by series: (work in progress)
System 1
System 80/A/B
System 3

System 1
		The easier ground modification if the game is working, and you want to *KEEP* it working!
		Recommended ground modification to System 1 regulator/power supply if you have to take it apart for service

Please note that ALL Gottlieb Electronic pinballs have problems with the ground connections. This stems from their refusal to learn from Williams, Bally and Stern's use of the metal shield as a ground plane for the game boards. Gottlieb System One pins had only a single ground pin going to the regulator supply, and this would weaken over time the same way as the System 80(X) problems are covered below. A simple cure for the System 1 and 80(X) regulator supply ground problems is to connect the ground plane of the regulator circuit board to one or two of the studs that the securing screws use to hold the circuit board to the regulator's heat sink, and then making sure that the heat sink frame is connected to the cabinet ground plane. All you need to do is add a wire from the (-) end of the large filter cap to the bolt on the underside of the frame - see the photo. If you have to take the supply apart for repairs then here is a picture of the mod done to a System 1 power supply (the BLACK wire), also note the fresh heat sink compound (silicon) on the both the outboard +60VDC regulator transistor and the -12VDC regulator.

I now recommend the adding of ground wires from both the MPU and driver boards and screw them under a screw on the rear metal panel. (See the pictures on the left...) The ground wire on the MPU is best if soldered to the bottom of C16 . The ground wire from the driver board would be easiest if soldered to the bottom of C1. Now these two ground wires go to the grounded frame of the power supply. (updated Oct 1, 05)

>>>NEW<<< The System 1 Audio board uses a separate +5VDC regulator, and if it's bolts are loose there is the possibility of damage to the TTL circuits on that board. So tighten the bolts! In fact it would be best if you put star washers under both the bolt and nut to make a better ground connection between the case of the 5VDC regulator (LM309K) and the ground plane copper on the underside of the sound board. You might as well run a jumper from this ground to a good tie point along with all the others.

System 80/A/B
		1st - check if the game still has this Orange capacitor - replace it if so, they are all bad!
		2) Next add a ground jumper wire from the capacitor on the Voltage Regulator board to it's frame- sand the black coating off the plate though.
		3) Next add a jumper wire from the MPU to the Regulator frame. Then jumper the two green wires on the side plug to the regulator to the frame (this will help with display flicker that sometimes occurs or pop bumpers that die for no obvious reason...)
		4) Then flip over your small sound board (early System 80 games-Time Line, Spiderman...) and add that ground jumper (goes to frame of Regulator)
		5) If you have the Sound/Speech board (Volcano, Mars, Black Hole,...) then it should help if you add this ground wire. Then do the next step down!
		6) And this ground wire is then recommended on the regulator for the Sound/Speech board...
		7) If you have a light chaser (Volcano, Mars, Black Hole,...) add a ground wire to it as well.
		8) And of course it is ESSENTIAL to add this ground wire to the Lamp/Solenoid driver board - goes to the Regulator frame...
		9) Lastly, run a jumper wire from the Regulator frame to the ground wire on the headboard lock or speaker frame, and for the best reliability it would be a great idea to run a separate ground wire to the copper metal strip that has all the wires soldered to it in the bottom of the cabinet just beside the transformers. See top picture in this section (Orange capacitor)
System 3 (System 80B similar)
		Find the power supply (under the playfield folks ;-)
		Tools etc...
		Replace these plugs with these crimp connectors
		Strip wires for each plug and insert into crimp connector - you might want to solder the wires to the crimp connector (I do).
		Secure the new connectors under a mounting bolt or...
		Bolt directly to the metal transformer box.