[Elecraft] KX-1 Did I blow my final?

Brian Wruble [email protected]
Tue Feb 24 14:49:11 2004


Hi all:

I had a working KX-1 with 30M module installed.  Measured power output was
2.5W on 20, 3.4W on 30 and 3.25W on 40.I installed the antenna tuner, and
everything looked fine.    

I then did the KXAT1 power calibration, and the null on adjusting C9 was, as
predicted, very sharp.  Then it dropped to zero.

I still had Xmit signals that I could hear on another rig, but much weaker.
Power output had become nearly zero.

I removed the tuner, replaced the jumper at J8, but still very little rf
power output. 

All operations were using a 14V power supply.  I used a DL-1 dummy load, and
I measured power using a DMM and using the conversion equation provided in
the DL-1 instructions.  I left "Tune" on for under 10 seconds each time.

I have checked T1,L3,L1,L2 all ok.

DC voltages at Q1,Q4,Q5,Q6 are all ok.

I have RF at T1, lead 4, but no RF at the collector of Q6.

I tried a reset of the firmware to factory defaults, but no help.

My quick diagnosis would be a blown Q6, but I'm surprised if it happened
that easily.  Is 14V too much for a short transmit period?

Any other ideas as to what to try would be greatly appreciated.  

Tnx.  

Another quick question:  The schematic showing J8 mystifies me.  It looks
like its pins are already hardwired together.  I can't quite figure things
out there.

73 de Brian W3BW