[Elecraft] [K2] Low sensitivity with variable-bandwidth filter

[Don Wilhelm]

Bill,

First try removing the KSB2 - put bent wire jumpers between pins 1 and 3 
of J9 and J10.  Then see if you get a good response in CW.

Oh BTW, make sure the CW filters are centered at your sidetone pitch 
first - use an audio spectrum analyzer and if you have one, a broadband 
noise generator (if not, use band noise, but make sure there are on 
signals on the band segement used).

If the CW filters work OK with the KSB2 removed, the troubleshooting 
should start with the switching diodes on the KSB2 option.

73,
Don W3FPR

On 6/11/2019 2:53 PM, Bill Coleman wrote:
> OK, I have a K2/100 w/ KAT100 that may have recently suffered from a static discharge event. I had to replace D16 & D17 in the KPA100, and I’m likely to do the same to the SWR bridge diodes in the KAT100 (since I can’t get the bridge to null properly).
> 
> The other thing I noticed is that the receiver sensitivity is substantially lower when using the CW filter. Using OP1, it seems to receive normally. I have three filters for CW 1.0, 0.4 and 0.16. When switching to 1.0 from OP1, signal levels drop by about 2-3 bars on the S-meter.
> 
> Anything in particular I should troubleshoot?