Remove the power supply, take good pics of the front and back.

The 2 black connectors at the top of the board are installed backwards. Now I don't know if you installed the wires on backwards or not, but if you did it would account for the fuses burning.

I zoomed in on the picture and can see that the cut header pins are reversed too. So this tells me you did connect the wires backwards. Remove the header pins and replace them with new.

I'm not sure if you have damaged other things by doing this, so after you get the headers reversed you need to only connect the large rectangle plug at the bottom of the power supply. Then turn on the power switch and then test the power supply for the correct voltages.

No, not for what you did. You need to leave off the smaller top connector and replace f-1. Then power up the game and see if f-1 blows now. If f-1 still blows with the smaller connector disconnected then you have a power supply problem. If it doesn't blow then you need to test the pins for the correct output. Let me know what you find.

OK, so the high voltage is messed up. This is why I wanted you to test the voltage before connecting the displays up. Most likely the displays were damage anyway.

Now do you want to fix this power supply or not?

Sounds good.

Now if there is a short on the display driver, it might cause the repaired high voltage section of the power supply to be damaged again. So it can be a gamble to plug in the displays to test. Your call now.

UND chips aren't available anymore so I wouldn't rebuild the HV section again, I would just get a led display. Once you're up and running, with displays working we can test the sound board.

I have not had good luck when I used these knock offs chips so I stopped repairing display driver boards.

How did you test the sound board?

Yes, but I think the CPU would not be booting up then.

This is not true. The sound board makes only some sounds. The cpu makes some sounds and speech. Both of the sounds and speech pass thru the cpu and are combined together and then amplified and go to the speakers. If you want to test the cpu board by itself you need to remove the jumper from 1J16 and then remove the volume control connector from the sound board and install it to 1J16 of the cpu board. Then you can run a sound test, you will be missing some sounds but have some sounds and all speech sounds.

You need to test with a logic probe the signals on J-22, J1,J2 and J3.

You have a issue with the blanking signal. You need to start with that first.

I think you jumped to a different trace. These pulses goes to U-36 pin 13, this plays a part of the blanking signal tho.

Correct, the pulses from U 51 reset U 43 which then the output pin 3 goes low. Q-50 might have been damaged from the voltage spike.

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