Following WA6HHQ Eric's directions to measure current draw, I realized that I had low output on all high bands, not just 10/12m.

Using the TX signal tracing procedure in the manual, I isolated the problem to the TX mixer buffer amplifier, and found it.

Now I have plenty of output on all bands. Thanks for all the help Eric and Mychael, and for the great troubleshooting in the manual!

Details for the record:

• U9, the TX mixer output buffer, showed approximately unity gain on all bands.
• I wicked and redid the solder joints of U9, to no avail, so I decided to check the buffer circuit components.
• Sure enough, I had neglected to install C150 on the bottom of the board.
• I even found the 330pF capacitor in my bag of "parts left over," hi hi.

- posted by Leigh @ 01:55 z