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PP7A is a switching power supply located in a metal cage on the left side of the monitor (in a cabinet shown here), behind the coin mechanics and the coin box.
On the top of the plug you can check voltages by applying the probe during attract mode.
In a working game they were:
| pin | voltage | pin | voltage | pin | voltage | pin | voltage | pin | voltage |
|---|---|---|---|---|---|---|---|---|---|
| 6P-4 | 4.88 V | 6P-6 | -5.07 V | 6P-3 | 12.04 V | 7P-1 | 0 V | 9P-9 | 23.33 V |
| 6P-5 | 4.88 V | 7P-7 | -5.06 V | 7P-5 | 12.04 V | 7P-2 | 0 V | ||
| 7P-6 | 4.88 V |
9P-8 | -5.04 V | 9P-4 | 12.04 V | ||||
| 9P-6 | 4.86 V | 10P-1 | -5.03 V | 9P-5 | 12.04 V | ||||
| 9P-7 | 4.83 V | 10P-2 | -5.03 V | ||||||
| 10P-9 | 4.83 V | 10P-3 | -5.01 V | ||||||
| 10P-10 | 4.86 V | 10P-4 | -5.02 V | ||||||
If you have a defective power supply and you are not willing or able to repair it you can easily replace it by using two switching power supplies, one for the +5 and the +12 volts and another for -5 Volts.
The reason for the necessity of two supplies is that the CLK board with its ECL
logic draws a large current of several amperes at -5V.
The original power supply has the following specs
| +5 V DC | up to 7.5 A |
| -5 V DC | up to 6.5 A |
| +12 V DC | up to 100 mA |
| +24 V DC | up to 200 mA |
The 24 Volts are being used for the game counter and can be omitted if necessary
A very good replacement for the PP7A power supply are two PC power supply units from old PC's. I used two identical Magnetek power supplies which are too weak for modern PC's (only 65 W per unit) but can be used as a Nintendo replacement PP7A without problems
You will have to wire them in the following way:
