[Elecraft] My K1 Learned a new trick.

[Don Wilhelm]

Bill,

In your case, there are two things to check - the T/R switching and the 
receiver muting.
The receiver muting is the easiest - is Q10 working is the question.  If 
the gate of Q10 goes to 6 volts during transmit, but the audio is not 
muted (except for the sidetone), then Q10 may not be doing its job and 
deserves replacement.
If it is a situation with the T/R switch, the problem is more complex.   
I can give you some points to measure DC voltages if Q10 does not cure 
your problem.  You may have the skills to figure out the voltages that 
should be present in the T/R switch diodes for both RX and TX.  If not, 
send a private email and I will try to help.

73,
Don W3FPR

On 3/13/2015 4:18 PM, bill m via Elecraft wrote:
> My K1 SN1730 has unfortunately learned a new trick.This radio was my first Elecraft kit many years agoand has been a rock solid reliable radio until a few days ago.I started getting a little squeal through the speaker on transmit and it quickly went away and the radio started acting like it's own transmitter wasoverloading the AGC and shutting down the receiver for a couple of secondsor longer. Sometimes requiring a restart on the on off switch to get it back. It happens on all 4 bands. The attenuator will sometimes reduce the effect, but not always. I had recently installed a new vfo pot (steel shaft) as well as the littleK6xx tuning board. Both seem to work quite well and appear not to be related to this.Looking at the schematic, maybe Q4?I'm hesitant to test this much with the key down to do signal tracing due to possibly damagingthe receive section.Suggestions? Don, Mike, Gary??ThanksBill