Pinbot sound not working. Ideas? I tried reseating all connectors. Still loud hum only. Hum doesn't change with volume knob. No "bong" on boot (though it never had one). Pressed top of 2 switches on CPU but no sounds.

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Bump

Thanks for the response. Kinda a novice here. How and where do I test the voltage?

Yes. That is helpful. Thanks.

Update. Here is what I've done so far. Tested voltage at MPU J17. All good. Tested voltage at sound board at J3. All good. Tested volume pot for ohms function. All good.
I need an idea of what to check next. Im guessing a component on the sound board is bad. I only get a loud hum theough the speakers that does not change when turning the volume pot. Any help appriciated.

Here is a post from google group rec.games.pinball with the exact same problem as mine.

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UPDATE. FIXED! Replaced the 3 op amp chips on the sound board with new sockets and also all of the capacitors on the soundboard as well. My friend Eric did all of the work on the board. Everything now works. Most likely it was the op amp chip but it doesn't hurt to replace the capacitors on a machine this old.