[Elecraft] [K2] K2 Rx or XG1 Problem?

[Brian - N5BCN]

Hello all,

Per a previous post, I was having problems getting the AGC Threshold Voltage
adjusted properly and the S9 on the S-meter calibrated (CAL S HI for S9
using XG1 was extremely low, at 002, compared to CAL S HI set for
sensitivity, at 017).

It was suggested there could be a receiver gain problem, and the first step
was to use the XG1 to perform an MDS calculation.  It should be noted that
I've been able to hear signals quite well, although I have no basis of
comparison, with the K2 on both 20 and 40 m.

Unfortunately, when I connected the XG1 to measure MDS, I hear no volume or
signal strength difference when I switch from 50 uV to 1 uV.  I've tried
listening to its harmonic on 20 m and the signal was extremely weak.  Can't
hear it's third or fourth harmonic at all.

I want to hope the problem lies with my XG1 and not the K2, but I'm not
sure.

Although I haven't started signal tracing the K2 (won't be able to get to
that for awhile), I did do resistance checks on the XG1 and found some
problems:

Resistance from the following junctions to ground:

U2, R1 = 50 k Ohms (should be 57-63 k Ohms)
C4, R3 = 50 k Ohms (should be 57-63 k Ohms)
R1, C1 = 54 k Ohms (should be 67-73 k Ohms)

Checked all component placements and solder joints, no obvious problems. 
Reheated all solder joints just in case; no improvement.

What makes this situation odd for me is the K2 receiver SEEMS to be working
ok as I can hear signals and the XG1 SEEMS to be working also (other than no
volume difference between 1 uV and 50 uV), but clearly one or both are not
functioning properly.

Well, it appears signal tracing is in my future.

73

Brian - N5BCN
 

-----
K2 #6800 KSB2 KAT2 KIO2 KNB2
-- 
View this message in context: http://n2.nabble.com/K2-Rx-or-XG1-Problem-tp4030138p4030138.html
Sent from the [K2] mailing list archive at Nabble.com.