[Elecraft] K2: AGC Threshold Too Low?

[Sarah K.]

Hi,

I'm Sarah, AF6FH! I just got my license a couple weeks ago, and I'm
now assembling K2# 0622, which will be my first HF radio. I started
assembly on Wednesday night, and so far, everything's been going just
fine.

But...

I'm having a little issue with setting the AGC Threshold.

The instructions (pg. 48) say to set the RF GAIN control fully
clockwise, measure the voltage on pin 5 of U2 on the control board,
and adjust trimmer R1 for a reading of 3.80 volts.

I did my voltage measurements with my own (cheap) DMM, not the
internal voltmeter.

My concern is that, by adjusting R1, the highest I could get the
voltage to go was 3.59v, so for the moment, that's where it's set.

I measured the voltage on the LM29307-8, and it has 12.23V at the
input, but only 7.53V at the output. The 78M05 has 4.93V at its
output.

When I rotate the AF GAIN control, I get a range of 4.68V (fully
counter-clockwise) to 3.59V (fully clockwise) on pin 5 of U2.

My power supply is a small benchtop power supply; it's putting out
12.4V, and reports the K2 is drawing about 100mA. When I measure the
input voltage across the K2 input jack, I get the same 12.4V.

All of the previous checks were fine, and the following step, S-Meter
Alignment, seemed to work just fine.

So, my question is, do I have a problem? Should I be concerned?

Thanks,

Sarah AF6FH