Using my spectrum analyzer, I placed an RF sniffer probe near the output connector of the of the HF amp board. I saw activity at the proper frequency, but at a very reduced level as compared to what I saw when transmitting on the 6 meter band with the probe near the 50 MHz output coax.
I've looked at the HF amplifier schematic in the service manual, and it shows what I assume are DC voltages at various points around the board. Some points show only a single voltage, and other points show a second voltage in parentheses. I assume that the first voltage is measured in the receive mode, and the second voltage (if present) is measured in the transmit mode.
I don't see any references to what HF levels I should see at the various points in the signal chain.
I'm thinking that the low output is due to either a failed transistor (or transistors), a problem with the level of the RF input to the board, or a poor connection at one of the connectors, but without knowing what the expected RF levels at the test points are, I would just be guessing.
Any help on how to proceed from here is appreciated!
73,
Stan N6BYU
