[Elecraft] K3 won't unkey properly: Rear panel PTT

[Don Wilhelm]

Dan,

Yes, if you have both the CAT PTT turned on and are using the SL PTT 
line, that may cause "strange happenings".  Good to hear that you now 
have a handle on it.

Let me throw in a suggestion since you say it has been working before - 
look carefully at your serial port or USB to serial adapter (or the CAT 
output of the SL).  It may have developed a hardware fault on the DTR or 
RTS signals.

73,
Don W3FPR

On 7/14/2014 12:23 AM, Dan Sherwood wrote:
> Don,
>
> If I'm not mistaking, all the signalink does is use a relay to ground out
> the PTT line voltage, much as a foot switch would do.  A logic high on the
> PTT center pin would indicate a key up condition and should cause the rig to
> return to receive state.
>
> I could see where a flaky pull-up resistor could float the pin and cause
> erratic behavior.
>
> I yanked the PTT line, but the problem persisted.  I would think it would go
> unconditionally to receive.  If it went high, it did not cause the rig to go
> to receive.
>
> The good news is I'm beginning to see the possible cause of the problem, and
> it appears to be in the CAT rig control.  When I finally get CAT disable,
> requiring a restart of FLDIGI, the problem seems to have mitigated.
>
> Funny how you can run a configuration for 2 years and never have a problem,
> until one day "poof"!  Perhaps the issue is software related after all.
>
> 73,
> Dan
>