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I purchased the radio with this symptom. ?Everything seems to work for VHF/UHF. ?This means the driver is functioning. ?When I trace the HF signal with a scope past the driver I do see a signal that varies with the power adjustment. ?This indicates to me that the ALC is functioning. ?The finals were removed and checked good with a transistor checker. ?The HF signal through the driver output seems to lose amplitude down the path through the finals and is negligable at the antenna connector. ?All this through a power meter and a dummy load. I would appreciate any suggestions or help to diagnose the problem.

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Tommy KF4RWGL

Hi Tommy

check the components within the boxed lines in the below picture .

make sure the correct LPF is active for the selected band in use.

James

are there any indicators like tx power level and check current draw.

is the power being throttled ? Any heat being dissipated due to current draw? look for hot spots

James,

All functions work on all bands for receive.? Because of that I believe the filters and switches are functioning properly.

There is no SWR, power meter or ALC meter for HF transmit at any power setting.? Only a very slight deflection at the external power meter (less than 0.25W).? The deflection increases slightly for 10 meters and 6 meters but all well below 1W.

It is just not amplifying significantly beyond the driver.

I am puzzled

Thanks

Tommy KF4RWG

Hi Tommy

not easy to find these type of issues, check dc voltages around the final circuit, coupling capacitors and switching devices.

Good luck

james

Signal level tracing with a 'scope is the way to go, looking at the levels in and out of the driver and to the finals.?

It is always possible that there is a problem past the finals as well.?

Sometimes you just have to drag out the test gear and take a look.