[Elecraft] vexing K3 transverter ptoblem solved

[Lewis Phelps]

For what it’s worth, I thought I would pass along my recent experience with a vexing transverter problem, and the cause of the problem that I eventually identified.

The issue was that my XV432 would light up its power output LEDs  ever so briefly when the transmitter was keyed, and then shut down. It was pretty obviously a shorted output situation.

I first assumed it was a faulty coax cable connecting either the K3 to the XV432 or the SV4 32 to the antenna. So I substituted different cables all the way around, with no benefit.

I even tested the hypothesis that the dummy load had gone bad, and substituted an older and smaller dummy load. Still no joy. 

About the only thing left in the chain between the K3 and the XV432 was the KXV3 transverter I/O board. Upon initial inspection, I saw that it was wobbling back and forth about 1/4”.  Upon closer inspection (requiring removal of the side panel of the case) it became clear that a 1/2” long 4-40 machine screw was missing, allowing the board to flex backward and forward, and apparently shorting the output.  

I replaced the missing machine screw, tightened the other machine screw on the opposite corner of the I/O board, and the problem was gone.

Moral to the story:  mechanical problems can cause electrical problems. 

At least I got it fixed in time for the upcoming VHF contest. 

73,

Lew 

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10 
Yaesu FT-7800 
Lew at N6LEW.US
www.n6lew.us

"The greatest tragedy in life is the gruesome murder of a beautiful theory by a brutal gang of facts.”