[Elecraft] K1 problem with transmit alignment

[n2htt at optonline.net]

I purchased a used 4-band K1 from another ham which worked well until the weather began to warm up when I started to get the dreaded "PLo" errors and 0.1 watts out.

I ordered the replacement cap kit, and the removal of the old caps and installation of the new went smoothly.

Now I am having trouble with transmit on 20m - I can only get 0.5 watts out on this band.

I carefully went through the 4-band filter transmit alignment twice. On every band, with the output set for 2.0w and R36 jumpered, I get a peak of 2 - 3 watts measured on a separate wattmeter. (Oak Hills WM-2).

After removing the jumper from R36, I measure a maximum output on all four bands (40, 30, 20, 15) of 7 - 8w. 

When I re-install the ATU, and set the output for 5w, I get 4 to 5w out on 40, 30, and 15, but only 0.5w on 20.

I'm not quite sure what the next step should be, since 20m looks okay before I install the ATU. 

Any thoughts?

Thanks,
Mike N2HTT