[Elecraft] [K3] Low output 160/80m

[Allan G Duncan]

I recently acquired a used K3 from a silent key with a large number of
options fitted. I already own another K3.

 

I have stripped it down to be a K3/10 to simplify fault finding. The only
option fitted now is a KXV3 interface. I fitted the bypass link in place of
the KPA3. All tests are done with a high quality 50 ohm load.

 

There is no RF output on 160m and only about 4-6W on 80m (It varies in
level, presumably with ALC action). The other bands are all fine on both RX
and TX. Receive on all bands (including 160/80) measures OK using my XG3 as
a test signal. Using a 50MHz scope around the BPF area does not show and
obvious fault with the K3 in TX mode with a cw carrier. The RF power output
control works as expected on all bands except 160 and 80.

 

The TX Gain calibration routine in the K3 Utility fails immediately as the
first band it tries is 160m.

 

I'd welcome any comments before I start swapping boards between my two K3's 

 

73

 

Allan

GM4ZUK