My Argonaut V has recently developed an intermittent
transmit problem (receive mode is normal). When I key
the rig in CW the side tone is present, the output
meter shows zero and I get no output on my external
watt meter into a dummy load.
This occurs on all bands and all modes.
Then just as suddenly it recovers and I get full
output. I have measured the "T" voltage to the low
pass/power amp board and it's present when I key the
rig at both full output and zero output.
It looks like the fault may be in the final and or
driver transistors. I plan on checking the coax
(Cable #16) feeding the board to see what if any RF is
being delivered to the final amplifier. My plan is to
disconnect the cable and look at the RF envelope on my
scope. Assuming it's present, what sort of output
would be anticipated?
The finals are a pair of 2SC1970 driving a pair of
2SC3133. Final output is about 21.5 watts.
Thoughts and or suggestions appreciated.
Thanks.
73,
Rick
VE7TK
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