OK Im still working on a Firepower and there is one issue left, the sound.

First there was no sound so I did all of the basic steps

Desoldered and reflowed all of the Headers and any suspicious pins

Cleaned off prior poorly done rework.

All new caps, fuse holders and fuses installed

All socketed chips cleaned of gunk all sockets cleaned

All connectors inspected cleaned and tested

This was done to both sound and speech boards and ALL traces were tested for continuity.

Test point voltages are perfect.

Boards were than cleaned.

Once that was done I had sound.

Sound in Test is perfect both speech and background.

The issue is that the sound would loose half of what I am guessing is its signal or part of it during gameplay.

On occasion it would work perfectly but mostly sounds(Background) sounds not speech would drop out and on occasion when the game ends an unusual background sound would continue until the machine was turned off and then on again.

I noticed that the amp and the heatsink were loose and when, on occasion, all sound would go out and I moved the heatsink by hand it would return or fluctuate while moving it, from nothing to very loud. but with the same issues

I saw that there was prior work done on the amp so I just decided to replace it and rework /clean up the area and use new thermal paste as the old had turned to useless powder. the heatsink and amp were then solid and not loose and flopping.

Now the sound never fails completely but the other issues remain (Background sound dropping out and sometimes sound remaining when game is over) I am guessing it is one of 3 chips, if so, is this a typical issue and could someone tell me which may be the culprit? It would save me time shotgunning them thanks.