[Elecraft] PA Problem

[Jim Brown]

My K2/100 with KAT100 was about a year old when I bought it six weeks
ago from a ham who needed the money due to layoff. It looks quite clean
inside, and it's worked fine through a couple of fairly intense
contests and some intermittent operating, but just started misbehaving
tonight. 

I use the rig with two reasonably trap dipoles that provide a fairly
good match before tuning on 80, 40, 20, 15, and 10. Any good tuner,
including the KAT100, gets them close to 1:1. I also have a Ten Tec
tuner with SWR meter in line with the 80/40 dipole. 

Earlier today all was fine. I found myself with some time to study the
K2 manuals to get more familiar with it, and worked my way through some
of the menus that I hadn't spent time with up to now. I ran through the
PA and ATU menus, but didn't change anything. I did change the t-r
timing from the default to 0.0 to see what it would sound like. 

A few minutes later, I heard some DX on 40 and gave a quick call, and
the rig sounded sick -- hum in the sidetone and high reflected. After
checking everything I could think of and powering off and on several
times, it's still doing the same thing. If I drop the power down to 10
watts so the PA is off, the K2 works fine barefoot, the KAT100 tunes to
1.2 and then lights to 1.3 or so, and the reflected  reading on the SWR
bridge in the Ten Tec tuner (the Ten Tec tuner is in bypass) doesn't
move away from 0 with full deflection forward.  

I've hooked a 50 ohm dummy load to the K2/100 (i.e., bypassing the
tuner) and the high reflected problem is still there if the PA is
running (but not with the K2 barefoot).  I don't see how the PA could
be hot -- all I've done is quickly hit the key and it immediately gives
me the hot and high reflected messages, and has the buzzy note. I've
tried powering off, letting it sit to cool, and powered back up. No
change. I've also tried different antennas and different bands -- 80,
40, and 20 -- and the problem is the same.  

Some other conditions: This rig is sitting in front of a window with a
bit of a breeze (the window doesn't close very well because I've got
some temporary coax lines coming through it), and it's turning cold in
Chicago tonight. As a result, the rig is cool to the touch -- well
below room temperature when I first observed the problem. The rig has
not been moved, nothing has changed in the setup or hookup. 

I suspect some sort of CAL problem related to the screwing around I was
doing in the menus. Any ideas?  

Jim Brown K9YC