On March 9, I posted the following:
"My K2/100 #1130 has developed an odd instability. When first turned on,
the
receiver seems unable to "lock on" frequency, so that CW signals have a
warble to them. After a few seconds to a minute or more, the receiver
stabilizes. The instability returns after each band change and often occurs
when I change the XFIL setting. I don't know if this condition manifests
itself in the transmitted signal.
<snip>
Do any of you kind souls have an idea where I should concentrate my
trouble-shooting efforts? I receive postings in digest mode, so direct
e-mail as well as posts to the reflector would be most appreciated.
I'll endeavor to inform the group of the outcome."
Rich Lentz, KE0ZX, came right back with this advice:
"My best guess is that you neglected to solder a pin or have a cold solder
joint on U4 - the PLL synthesizer. Quite often an un-soldered pin will work
for a year or more, then oxidation causes it to go intermittent and then not
work at all. Check solder connections for the parts on the top half of
sheet 1 of 4 of RF Board.
Next I would check voltages and that should give you an idea of where there
could be a problem."
I finally got around to tackling this job today and am very pleased to
report that Rich was "right on" when he suggest checking connections around
U4. I resoldered perhaps 50 to 75 connections and, when I put the rig back
in service, the instability had gone. (BTW, the transmitted signal was also
"rotten") .Thanks Rich!!
Listen for this old road warrior (the rig, not me) K2/100/M as it traverses
the RARE counties of Michigan's Upper Peninsula in the MiQP test April 16.
I'll be QRV mostly on CW with some forays into the SSB portions of 20, 40,
and 75M. See http://www.miqp.org/ for the particulars.
73
Todd
N9NE
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