I've owned the S-24 ( & 32) for over 13 yrs & had the SAME ISSUES. I eliminated the prob by thoro'ly cleaning channel faders 1-8 & 9/10-15/16, all channel inserts, line ins, group/main ins-outs & back ADAT RCA's ins/tape outs etc. LED indicators on trks 3&4 were dimly lit so I went inside board...