[Elecraft] [K2] K6XX zero beat indicator and the "Spot" function

[Christopher Kimball]

Thanks for all that have responded.

I've installed a 100 K series resistor in the audio input as suggested.  
The problem continues, however.

In messing around with the unit, I attached an EZhook cliplead to the 
audio input at the board-connector.  The cliplead is attached to a wire 
about 1 ft long with another EZhook at the end.  Nothing is attached to 
the other end, however.  When this is done, the indicator works 
correctly, with no-signal responses to very few noise bursts and correct 
operation on signals, at full RF gain.

The cliplead seems to be injecting noise into the audio line.  If the 
other end is connected to a 1 M resistor to ground, the needless 
blinking resumes.

This suggests that the K6XX board may be defective. Further ideas would 
be appreciated.

Chris Kimball
WB4WZR