[Elecraft] K2 20 Meter problems.

[Ron D'Eau Claire]

Since all the "active" components are used on all bands (with the =
exception
of a couple of relay contacts), I'd look for:

1 - An unsoldered joint that has been making mechanical contact. Over =
time
oxidation will open the connection and suddenly things stop working. =
Such a
joint would be in a 20-meter specific part of the circuit, probably in =
the
bandpass filters.

2- A bad trimmer cap in the 20 meter bandpass filter.

I'd tackle (2) first. These caps have a sliding contact for one side of =
the
cap, so you can turn it. Some of the caps were shipped by the original
manufacturer still needing "seating". Builders discovered that the rig
didn't work on one or more bands until the caps were spun around several
times to establish good electrical contact in moving section. Perhaps =
yours
worked from the start, but that bad connection has now appeared to =
"haunt"
you (considering the time of the year...). Anyway, I'd suggest first =
giving
the 20 meter adjustment trimmers a good exercising - spin them around a =
half
dozen times at least, then try adjusting the filters per the manual and =
see
if you get output. If that works, you're probably fine. Once those =
trimmers
"seat" and make good contact, they seem to be fine indefinitely.=20

If that doesn't work, then I'd recommend carefully checking ALL the
connections in the 20 meter bandpass part of the circuit for a bad or =
missed
solder connection. Pay careful attention to the toroidal leads and how =
they
are soldered onto the board - especially if you wound your own.  A =
"Poorly
Tinned Toroid Lead" (PTTL) usually turns up right away, but it's quite
possible that one has been lurking for some time.=20

Lastly, I'd check continuity through the relays to see if a contact has =
gone
bad. I haven't seen a report of a worn-out relay yet on the reflector =
here,
so I'd consider that the least likely possibility.

Ron AC7AC

-----Original Message-----
I have a K2 that recently developed a strange problem on 20 Meters. =
Lately
it seems on 20 meters only I do not get any power out (well, maybe a =
watt at
the most, despite the power being set to 5). I tested this against a =
watt
meter. Also, the receive seems to be way down on 20 meters compared to
another radio on the bench. The SWR is fine, and I even tested it on 2
different antennas (1 wire, and one verticle). All the other bands have
normal power output and receive normally. I'm guessing maybe something =
went
out of adjustment?? Many thanks!=20

James Kern, KB2FCV _______________________________________________