Got a good one for everyone. I have a SBM that I'm bringing back from the dead. Everything seems to be working right now but no sound. Looking for a direction to look in.

All boards have been pulled, gone thru and all are working correctly (tested in other machine) including the sound card which sound was perfect in Viking. All voltages test correct/within range on the sound card. If I use the rebuilt -35 I can get the coin up tones out of it but the second you press the start button it dies. Altek board it is dead no matter what. Nothing in sound test, nothing from test button on card with either mpu. Re-pinned the 5v unregulated from rectifier board because the connector looked burnt. Pulled and checked ever pin from mpu and solenoid that passes thru the sound card. Speaker tested and second known working speaker both tested no sound. Checked continuity at all the connectors to and from sound card.

Any help would be appreciated

As a follow up, go some direction from someone off site and started going thru the header pins. After getting some noise out of the card from re pinning the mpu J4, I found a problem with the solenoid board. U3 seems to have a shorted leg and after swapping in and altek, sound fired up and played fine. Problem now appears to be somewhere else as chip blew out again on the original board after replacement.