Purchased a high speed with sound issues. Got the sound going by reflowing solder on some connectors and fixinna bad trace but the sound fx dont start until the game has been left on for 20 minutes and then they work perfect. If the game is shut off and back on immediately they still work. If the game is left off for 20 mins they will need to "warm up" again.

Any ideas ?

My understanding is that the sound board controls only the music which is working fine and the sound fx are located in the sound chips on the mpu. Would the same apply to caps on the mpu then ? Bad caps on the mpu would satisfy why music works properly and sound fx don't.
Can the capacitors be tested onboard ?

Voltages from the power supple are all good and the same when hot/cold. Will check 1J17 header pins tonight. Thx

All electrolytic capacitors on mpu have been replaced and 1J17 repinned. No changes, same problem. Any other suggestions ?

So a big thanks to Grumpy for the idea. I let it warm up and get to a fully working state and then placed a plastic icepack on each component for 20 sec. when I did it to the sound processor IC the sound fx cut out. Remove the icepack and they came back after 5 mins. Repeat several times and the same result.
So I got a new MC6802P and put it in and it works perfect without warming up.

I cant say that I would have ever thought of an idea like this. Dont know if its your idea originally or you heard it somewhere else but its pretty outside the box and genius and saved me when I was teally stuck. Now I'm enjoying my high speed as it should be.

Thanks !