For parts or repair only! Problem: Low volume output on all outputs. Everything else in working order. Very Clean!

What I did to try and fix/troubleshoot:
Instrument: 1998 Alesis QS8. Main board marked QS7/QS8 MAIN 9-40-1241-F.

Problem: Keyboard boots, responds to controls, and produces recognizable, correct sound, but volume is extremely low on Main L/R, Aux L/R, and headphones. The volume slider changes the weak signal.

Work completed: Replaced all three large power-supply electrolytic capacitors: two 2200 µF / 16 V and one 1000 µF / 25 V. Removed originals measured around 52% of rated capacitance. Replacing these capacitors did not correct the low audio level.

Additional Tests Performed Checked DC supplies around the analog/op-amp circuitry; no obvious missing rail was found. 5 V reading was approximately +5.14 V. Backup battery measured approximately 3.09 V.

Since the suspected issue is likely with IC Circuit, and I do not have the tools to properly diagnose the issue, I am selling it to someone who can. I bought it new in 1998 and still even have the original box. No stuck keys and the display/buttons/faders all work without issue.

It's a shame to junk a nice vintage synth that is in such nice physical shape. Hopefully you can pickup where I left off and bring it back to life.