Problem: Sometimes the RX sensitivity drops about 30db.
Conditions: This happens when changing bands and sometimes
when selecting PRE/ATT and sometimes when my
window A/C unit turns off (you hear a "pop" in the
K2's speaker when this happens). Sometimes it just
happens all by itself.
Temp fix: Tapping on Q22 "pumps" the gain back up in 3-4 steps.
By "tapping", I mean using the plastic handle of a small
screwdriver to tap with about as much force as pushing
a button on the K2. Sometimes though, I get the same
result by just touching the case of Q22 with my finger
several times.
Inspection: All solder joints in the area have been closely inspected,
then re-heated at least twice. I have put pressure on the
PC board (looking for a trace fracture) with no help
there.
Wierd Factor: Sometimes tapping Q12 has the same effect.
I've unhooked all the cables from the back, switched antennas and
changed from a SEC-1223 power supply/SLA battery combo to
just the SLA battery only. No change. I turned the radio off last night
and powered back on cold this AM with no change so I don't suspect
a thermal issue. Sometimes I "fix" the problem then it happens again
when putting the top cover back on. I bypassed my KAT2 and used
the old antenna jack - no help.
This problem has been going on for 24 hours. Note: It *never* "fixes"
itself - I always have to intervene by opening up the rig and tapping
Q22.
Help!
--
Just my 2¢... 73 es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #-1055
Proud builder & owner of Elecraft K2 #4913
--
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