Caucasian Blackplate said:Did you end up needing to do anything to get 4.2V at pin A2?
The next test is to turn the amp on and measure the AC voltage at terminals 6 and 10 with a pair of headphones connected (always use a spare pair of inexpensive headphones for testing) and the volume about 1/4 of the way up.
I discovered I was measuring from the wrong pin. Then when testing A2 it read 4.2V. (still fighting a rookie learning curve)
Regarding the next step in measuring: I assumed you meant from ground to terminal 6, and from ground to terminal 10, as shown in the attached snippet. If I got it correct, the DMM gave me nothing (0.00V) with the volume approx 1/4 way up, cheap headphones plugged in, on both ground to 6 & ground to 10.