Hi,
may I relate my PA-story?
I built the 50-w-pa for 80 m successfully (I think? ;-)? ?). Yday evening I did some QSOs wid abt 25 w (power supply abt 14 V). My rig is the QCX mini. All was fine.
The next morning I turned on the PA first (QCX was off) and there was a terrible noise in the headphones (fortunately it wasn?t on my ears). QCX-display also lit up, all cables were connected. It was on for a few seconds. Also no good idea, that I pressed the key shortly ...
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I removed power-supply and all cables. There was no smoke but a little bit bad smell if I?m not wrong. Result: power output 1 or 2 watts only. The QCX itself is ok.
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I?m not a technician, but I made some measurements with help of the video from NA5Y.
The result: all is okay until minute 9:30.? The voltage on L10 should be abt 14 V in RX and close to ground on TX. This is not the case (only 0.25 V RX and TX). The following measurements are also incorrect. For instance R13 always shows 14 V (RX and TX). So I stopped testing.
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QCX was in practice mode during measurements.
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How could I tackle problems? Every hint is appreciated.
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Mni tnx and 73
Roland, OE5ARN
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Roland OE5ARN