Want to know which transistor drives which coil on your System-80 machine? Which transistor drives which lamp? Got a coil that won't fire or a burned out lamp or two? Here's a bunch of tables for as many Gottlieb System-80 machines as I have schematics for that will help you figure out which component is at fault.

I plan to add more machines as time permits and as I get more information. If you have information on machines that I don't have listed here, please send it to me and I'll post it here too.


Gottlieb System-80 pinball machines use a single driver board to drive both solenoids and lamps. These driver boards use transistors to drive both lamps and solenoids and depending on the load of the circuit, these transistors, and their quantities, are as follows (typically):
MPS-A13 (20 each) - Single lamps or under-playfield transistors (2N5875)
MPS-U45 (38 each) - Single or multiple lamps, relays, solenoids, or 2N3055 transistors
2N6043 (3 each) - Solenoid coils
2N3055 (3 each) - High powered solenoids
The three 2N3055 transistor (Q58, Q62, and Q64)) are actually driven by MPS-U45 transistors (Q57, Q61, and Q63 respectively), due to the high power demand of the associated solenoids, which is more than the MPS-U45 can handle. This three driver circuits were designed to drive solenoids that required a lot of power to energize (for example, resetting a bank of 5 drop targets). Unfortunately, the need for additional high powered driver circuits arose and presented a problem, since the driver board only had 3 such circuits. To solve this deliema, Gottlieb placed additional high power driver transistors (2N5875) underneath the playfield near the desired coil(s), then used the MPS-A45 circuits on the driver board to drive them. These high-powered transistors then drive the solenoids. These transistors and the ones on the driver board are easy to replace once the defective ones have been identified. Clay's System-80 Repair Guide tells how to identify shot transistors. If you'd like to find out which driver transistor goes to which driver connector tab, Click Here.

Finally, the driver board provides 5 signals to the System-80 sound board. The first 4 signals come from Z13 (SN7404); SOUND1, SOUND2, SOUND4, and SOUND8. The fifth signal, SOUND16, comes from Q10 (MPS-A13). These signals are decoded by the sound board to produce the desired sound effects.

Auxiliary Lamp Driver

Some Gottlieb System-80 pinball machines also use an Auxiliary Lamp Driver module to drive still more lamps. These auxiliary driver boards also use transistors to drive multiple lamps:
MPS-U45 (10 each) - Multiple Lamps

Click on a machine to see the info:

Black Hole

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Created 10/8/02 - Last Modified 10/8/02 - Steve Kulpa Mail Icon Nolensville, TN
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