Rich,
FWIW, I've had problems with my internal keyer also.? I've also added 6 ferrite beads to my keyer cable with some improvement but not yet complete success.
RF feedback is a common problem with QRP unbalanced antennas (EFHW, long wire, even trapped verticals) that is aggravated by poor or non-existent grounds with these rigs.
I've always been able to use my straight key, however.
All the best.
Jack
