R42 seems a bit light, but unless it's significantly drifting under load, I wouldn't worry about it. One way to tell would be to measure the voltage on either side of it. Do you have a replacement for Q16? ...or swap it with Q15? If that doesn't change anything, find the equivalent of a chopstick and tap on the L CH components -- specifically the carbon composition resistors -- and listen for a change.
Already replaced Q16 (see post #12). Will check the resistors...
Any chance this is a capacitor issue? I've only replaced a few caps on this board (ones I thought looked bad).