John, what I would be concerned about is that possibly you have +12 on the output of the mosfet switch (IRF4905) just like I had¡. possibly due to a failure of the 7002 on the output of the mosfet swhich (which is what happened to me) and that is causing continuous current through your output LPF diode control resistors and inductor, and may have already burned out your input diode control inductor which might be why the resistors on the input are cool ¡ª all speculation on my part but possible
There is probably another explanation as well but that fits sort of what happened to me in November
A bit of measurements with a voltmeter will figure this out for you. ?If the gate of the IRF4905 drops more than a few volts below supply voltage it will start to feed current to the transmitter stages.?
Gordon Kx4z?
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On Jan 4, 2024, at 16:29, John Terrell, N6LN <N6LN@...> wrote:
?This may or may not have anything to do with Gordon¡¯s R201-R202 smoking, but I notice that at power up R203-R204 run pretty hot, even without PTT or even without starting the sBitx program. Somewhere there¡¯s abou 500-600 ohms from the anode side of D30 to ground. There is almost a 12 volt drop across these resistors. R201-R202 run cool without any voltage drop. Is this normal?
Jack
N6LN
