Posted by
Evert Bakker (PA2KW) on
Apr 09, 2005; 12:38pm
URL: http://elecraft.85.s1.nabble.com/AGC-Alignment-tp376809.html
Hi all,
I'm assembling the K2 here (SN 4836) and came to the first
check/alignment. No smoke here so far, but when adjusting the setting
for the AGC as described on page 47 I became suspicious about the
alignment procedure. Adjust R1 for 3.80 V on the DMM. I turned R1 and
reached the end and got stuck on 3.78V. The absolute value of 3.78
doesn't worry me but that I ended up at the limit of the R1. I thought I
should check all variables like DC voltage which should be 8V (was 7.98V
so OK). Checked the resistors (mainly RP6 / 5.1K) and, RF gain
potentiometer 5K and the R1 (50K). All looked fine. So what's wrong?
I started making calculation on the resistor dividing network and came
to the conclusion that the maximum voltage (theoretically) could be
close to 3.82V when the RF-gain is fully CW (0 Ohm) and the R1 is set
fully CCW (50K).
I wonder if something is wrong here and if not, why was the alignement
procerdure setup like this (it could heve been something like: Set
RF-Gain full CW, R1 full CCW and check the voltage at pin 5 of U2 to be
close to3.80V)? Or did I miss some errata info?
Please help.
Thanks in advance
Evert, PA2KW
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