Check that both switches are set to ON

Sound commands are sent to the sound board through some of the solenoid outputs. If you have a logic probe, you can see if they are making it to the board by probing sound board J3 pins 2 - 8 to see if they are pulsing during gameplay. If they are, check the outputs of IC5 buffer pins 2, 4, 6, 10, 12, 15. If you have pulsing output there, I would suspect the sound board PIA.

I should have been more clear, the IC5 I was referring to is the one on the sound board.

Maybe a better way to test if the commands are making it to the sound board would be to test the input pins on the PIA pins 10-16. These should be pulsing during a game. If they are not, test the inputs to the buffer IC5 on the sound card.

If that is all working, check the output of IC6 pin 6 (also connected to the PIA pin 18). This should be low when not in a game (not playing any sounds) and high or pulsing when in a game playing sounds.

Sorry @owenkhan, I just now saw your posts in this thread. I wish Pinside had a notification system when people post to threads...

Since you are not seeing the signal on the sound board J3, your should move back to the driver board to see if they are leaving the driver board correctly. You could go back and test PIA pins 10-16 to doublecheck.

The sound commands leave the driver board at J9 which is the bottom connector on the left edge of the driver board. Sound board signals are on J9 pins 1, 2, 3, 7 and 9 (pin 1 is on the bottom of J9 when installed in the game). These should be high through the pull up resistors on the sound board in attract (no sounds) and pulsing when in a game.

DO NOT TOUCH pins 4, 5, and 6 of J9 with your logic probe or you may damage it. Those pins have higher voltage solenoids attached that may damage your logic probe. You can try setting your probe to CMOS that may provide enough protection from an accidental connection. Some probes have input voltage protection in which case, you can disregard this warning.

If you have the signals on driver board J9 but not on sound board J3, you have a wiring/connector issue.

What is the state of the rest of your Firepower? Is it 100% working otherwise? Was the sound ever working or is this a new acquisition? Have you bullet-proofed your CPU/Driver boards (replace 40 pin, reflow/replace header pins, replace Scanbe sockets, etc)?