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I'm sure this isn't new, but just to talk about my experience. My QMX has been working - Tx and Rx, but I hadn't used it for some time apart from some listening and testing of a mini antenna tuner. Today, there was no Tx o/p on any band and the hardware tests showed the same on pressing 'T' with a dummy load. I took the QMX out of its case and measured around the PA transistors, assuming there had been a catastrophic failure. The PA showed the correct drain volts, so nothing was short circuit. However there was no drive, which I traced to no Tx signal from the microprocessor on pin 2 etc of IC503, so the driver chip wasn't enabled. It didn't matter whether SWR protection was enabled or not. In desperation, I performed a factory reset, and this re-enabled Tx, so the microprocessor was happy and working again. Now I have to work out what settings I had tweaked, as my settings are now gone.

The processor seems a bit too sensitive to this sort of failure mode.

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73

Tony G3OVH

Practice mode? (But I don't know about PA drain voltage in this mode in the moment. Go back to my work bench in some days.)

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I don't think Practice Mode affects the pressing of the 'T' key in hardware testing - AFAIK it's only to stop the morse key from activating the tx.

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On Mon, Aug 5, 2024 at 11:34 PM, Tony Abbey wrote:

I don't think Practice Mode affects the pressing of the 'T' key in hardware testing

No, no transmitting when pressing "T" in P-mode. The PA voltage is switched on but no output.