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Hello all,

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So I updated to firmware 07 and wanted to run the calibration, but I'm getting PA modulation error.

Tells me to run the PA MOD test, but I just get a straight line.

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What can be causing this?

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Thank you,

F4JVU

That proves that the new test Hans added works correctly.

When the PA MOD test results in a flat line at the top, it means that the processor can't control the transmit voltage.? It should instead show a ramp up from 0.

This also means that if you go to the Diagnostic screen, in receive/idle, you will see a transmit voltage close to your supply voltage, when it should be near 0V (about 0.8V during receive).

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This normally results from a failure in either Q507 or the circuit that controls its gate.?? I think the most common issue is a failed Q507, especially if your BS170s ever failed.? See this post in the wiki:?

also a few message threads in this group recently addressed diagnosing failures in Q507.

Thank you Stan, looks like the Q507 might be dead. I am seeing full voltage in the transmitter part of the diagnostics tool.

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