Hi Michael,
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Start by checking if the tab (drain) of Q9 switches between 0 and almost the input voltage (12).? Q9 provides the power to the driver and bias stages.
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If the Q9 drain is not changing, verify that the TX signal (gate of Q10) changes between 0.6 volts and 3.3 volts.? That is the transmit signal from the Raspberry Pi.
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Once you get the TR switching working, then verify the voltages on the transistor sides of R10 and R49.? R10 will indicate that the predriver Q11 is at its operating point.? R49 voltage indicates that the four drivers are at their operating point.
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Once all the driver stages are verified to be at the operating point, switch to the RF probe sheet, CW mode, and the power settings to trace with the probe.
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Good Luck, and happy hunting for the problems.
73
Evan
AC9TU
