[Elecraft] K2 KNB2 Issue

[Nigel (Nidge) Smith]

Hi All

I have an elderly K2 which had the original KNB2 installed, the one with the two trimming capacitors in the
bandpass filter circuit.  I ordered the revised board and this was built yesterday.  The issue is that with
the new board installed the sensitivity is very much reduced which is confirmed using the XG3 at 50uV 
output, with the original board the S-meter indicates S9 where as with the revised board the S-meter
indicates S3.  I have checked that all the components are in all the right places paying particular 
attention to the capacitor values, that all the inductors have the correct number of windings and that
there is continuity between each end of the inductionr (0.04Ohm).

Is there anything I can further check?

Test equipment available:

XG3
50MHz Oscilloscope
MFJ Antenna Analyser
Fluke 77 multimeter with RF probe.

As an added bonus today I was using the K2 at a special event where we had multiple
stations running.  One of the other stations came on my frequency and transmitted.
The result (with the KPA100) installed is that I get a constant high current reading
on the display and SWR of 9.9, I’m presuming that the diodes D16 and D17 in the
KPA100 will have been fried (?)

All recommendations greatly received.

Regards

Nidge (G0NIG)

IO93dv