[Elecraft] 80 Transmit on KX1

[Bill Trettin]

I installed the KXB3080 option in my KX1 a couple months ago and everything
checked out OK after completion, including output on 80 meters.  

 

Now however, I am getting no output at all on 80 meters.   I am still
getting 5 volts output at point F, and current draw of the KX1 increases by
around 15ma when I select 80 meters, so it looks like the K1 relay is
switching as it should. 

 

I get the same symptoms whether the KXAT1 ATU is installed or removed and
replaced with a jumper.

 

I put a signal generator at the antenna connector and can trace a signal
through the RF section in any of the band positions but in 80 meters, I get
no signal at all, even at the J7 jumper.

 

I'm thinking when I switch to 80 meters and the K1 relay switches, it's
introducing a short somewhere on the KXB3080 board or possibly on the LPF1
board but I haven't been able to find it.  Has anyone else had this problem
or have any ideas?

 

Bill, KF8GE/HL9TY