[Elecraft] K2 #4115 transmitter oscillation

[Bud Rogers]

Here's where I am now.  T1, T2, T3, and T4 appear to be wound correctly.  
One thing that might be an issue:  the instructions for winding T2 show 
to dress the leads on the secondary side under the toroid.  I did that, 
but in the process of seating it down on the board and pulling the 
leads through, I managed to pull the leads out straight and snug.  I 
doubt that's the problem, but there must have been a reason for those 
instructions.

I can't find any components misplaced.  I touched up a couple of solder 
joints that might have been cold joints.  It still oscillates.

I took a little time to try to get a better idea of what it's actually 
doing. Tuning on 3600 and 7100 produces distorted output on the 
fundamental and on 2nd, 3rd, and 4th harmonics.  14100 and 21100 don't 
appear to have any ouput at all.  28100 has distorted output at the 
fundamental.  I don't have any good way to check for harmonics that 
high, but I wouldn't be surprised if there are some.

The lack of output on 20 and 15 leads me to think my problem might be in 
the BPF or LPF for one or both of those bands.  I have stared at those 
areas of the board through my magnifier light til I'm cross eyed.  I 
don't see anything out of the ordinary.

I guess I'll put it back together and start checking voltages on the RF 
board, maybe compare readings on 40 and 20 and see where that leads.  I 
would welcome any suggestions.

-- 
Bud Rogers	<budr@netride.net>
KD5SZ		EM05vb		K2 #4115