What could be the reason that IC18-P12 (Res) picks up the signals from all other Pots?
There do not seem to be any continuity or shorts problems around IC18, and the traces for P2.0 - 2.3 & INH2 are fine. The CPU should be okay too and I swapped new 4501 at IC18 & 19 at one point, and a second time reverted these and used the new 4501 on the two left-most panels.
Doesn't this narrow it down to either the DAC or the comparator at IC6?
Yash