Thanks for replying Alan. I replaced Q3 and the rig is back to normal - PTT is working OK. I must have shorted something while I was tracing the TX signal.
Now I'm going to continue checking out the low TX power issue as soon as I get time.
Thanks for the help.
--- In email@example.com, "Alan" <alan4alan@...> wrote:
> ----- Original Message -----
> Subject: [softrock40] Ensemble RXTX PTT Stuck On ABPF NOT enabled
> > somehow PTT got stuck on and burned Q3 to a crisp. ABPF is NOT enabled.
> > Before replacing Q3 (2N3906) I want to find out if something else is
> > causing PTT to stick on.
> > U1 pin 3 (the R11 hairpin) shows voltage of .01 with PTT OFF and 4.81 with
> > PTT ON. The R34 hairpin (base of Q3) shows 12.76 volts with PTT OFF and
> > 10.98 volts with PTT ON. Q3 has been removed at this point.
> The switching seems OK.
> If it was stuck on it would not damage Q3.
> What would damage Q3 is a short to ground at it's emitter.
> Measure resistance to ground at R37 hairpin. If less than about 1K then look
> for splashes. It may be that you caused a temporary short while testing?
> If you do not find anything replace Q3 but keep a careful check on the
> current when you test.
> 73 Alan G4ZFQ