I recently got a Raven machine with problems. I have most issues ironed out but sound issues remain. Voltages check out good, both cpu's replaced, led stays on, pressing the buttons do nothing. I will attach a sound clip of what it's doing. Any ideas would be appreciated. well I can't figure out how to attach a clip. It makes a constant humming sound with a escalating humming sound that last about 5 or 6 seconds then the original humming remains till I turn it off. Thanks

I've spent a little more time on this issue. I tested the sound board in another machine and it works. I changed z13 on the driver board, the CPU, all Riots, z13, and z27 on the mpu. I get clock signals, reset starts low and goes high address and data lines do pulse. A couple things I noticed If I unplug a3-j5 from the driver board I can get sounds by grounding the sound lines but not with it connected.
Also after about 5 minutes of running with everything connected the machine will start resetting and then stop due to the 5 volts dropping too low, if I unplug the sound board the voltage will stay at 5. Thanks.

It's fixed. Ended up being a bad 7404 at z13on the driver board. That chip was brand new so I didn't figure it would be bad but it was. Thanks.