I always start by testing the CW output to verify that the power amp is working.? If no power on CW then most likely it is a Q90 failure.? To test Q90 measure the voltages on each of the three stubs.? The values are listed in a spreadsheet that is stored in the files section of this board.? Search for vu2zap (Raj is the person who took and posted the voltages).? Note the test conditions that are listed in the spreadsheet, and be sure to have a dummy load (or tuned antenna) to the radio when transmitting.? Q90 voltages should be tested in SSB mode with no audio into the mic.
/g/BITX20/files/VU2ZAP73
Evan
AC9TU
