[Elecraft] K2 AGC Off Problem

[Darrell Bellerive]

Just finished alignment and test, part II of K2 #5093. All seems to be working 
as it should, except for the AGC off function. This problems appears to be 
the same as a few others have had, the cause of which was a bad 5.068 MHz 
crystal (X1). Perhaps I have the same problem.

When the AGC is turned off the S-meter pegs at 40 over and the receiver is 
muted.

The AGC threshold at pin 5 of U2 measures 3.8 volts whether AGC is on or off.

The voltage at pin 1 of U2 goes from 3.8 volts with the AGC on to 5.4 volts 
with the AGC off.

All components in the AGC circuit have been inspected again for correct values 
and placement. All solder joints have been reheated.

I cannot measure the 5.068 MHz oscillator with my frequency counter (MFJ-259) 
at pin 6 or 7 of U1. Perhaps this counter loads down the circuit too much for 
it to oscillate?

Listening with a portable shortwave receiver (5 kHz steps) finds a weak 
carrier at 5.070 that goes on and off with the power on the K2.

Before I email Elecraft support, what else should I check?

Darrell
VA7TO

-- 
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada