How to test a Space Invaders/SI Deluxe Power Supply

(Or any other game that uses the Midway A082-90400-x000 Power Supply)

Picture of a Midway A098-904 Power Supply

Basic Tests:

Step 1: Apply power, check for blowing fuses.

Step 2: Connect the negative (black) lead of your voltmeter here (set your meter to at least the 20VDC range).

Step 3: Test the +5V line. Connect the positive (red) lead of your voltmeter here. If needed, adjust the +5V line using this pot.

Step 4: Test the -5V line. Connect the positive lead of your voltmeter here. If needed, adjust the -5V line using this pot.

Step 5: Test the +12V line. Connect the positive lead of your voltmeter here. If needed, adjust the +12V line using this pot.

Step 6: Test the +18V line (this is for the sound amplifier). Measure it across the 1000uF capacitor. There is no adjustment.

Step 7: Test the RESET signal. Connect the positive lead of your voltmeter here. With the power on, it should be 0.5V or less.

Intermediate Tests (This only works if you have a digital meter, analog meters get confused)

Step 8: Repeat Step 3, except set the meter for AC measurements. The ripple voltage should be 50mV or less.

Step 9: Repeat Step 4, except set the meter for AC measurements. The ripple voltage should be 50mV or less.

Step 10: Repeat Step 5, except set the meter for AC measurements. The ripple voltage should be 50mV or less.

Step 11: Repeat Step 6, except set the meter for AC measurements. The ripple voltage should be 50mV or less.

Advanced Tests

Step 12: Using an oscilloscope set for 1V/div and 1msec/div, verify that after powering up, the RESET signal reaches at least 3.0V before settling to less than 0.5V in about 8 msec.

Step 13: With the power off, disconnect the motherboard and game PCBs from the harness. Leave the power connector to the power regulator PCB installed.

Step 14: Verify suitable +5V range adjustment using a 5 Ohm, 10W load resistor across the 5V line.

Step 15: Verify suitable +12V range adjustment using a 47 Ohm, 10W load resistor across the 12V line.

Step 16: Verify suitable -5V range adjustment using a 47 Ohm, 1W load resistor across the -5V line.

Last updated on 2/25/06