Hi Glenn,
The earphone jack gets its audio from just before the LM380 audio output circuit, so this would indicate that the LM380 chip is bad or the snubber cap C32 470ufd. There has been a few LM380 failures that I know of one of which was my sBitx V2 card i received. If you have the ability to change it that would probably fix you problem.
Joel
N6ALT
Joel Caulkins/N6ALT