Ok, my readings compensating T9 de-tuning
on 10m. All relatives, of course.
10m 30V 400mA 105W
15m 27V 420mA 135W
20m 28V 390mA 165W
See that with more or less the same "p-p drive level" I got higher
plate current (and higher output pwr).
Note that I modified the wiring around external RX switch: so when
I connect the scope there, there is not any extra coaxial run
between switch and antenna relay (less parallel C).
Seems that up to the 12BY7 things are ok. May be the finals
reached EOL.
73
Marcus PY2PLL.
Em 04/02/2025 13:12, Dave KD5FX via
groups.io escreveu:
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This is the same TR-4C that had the bad Xtals which were
fixed by a baking. The problem now is the output is very low on
15 and 10 meters. Someone suggested I test the output on each
band at the output of T9 which is on the driver. So I did and
here is the results. Also, I re-tested the driver tube and the
final, they all checked very good and I did a resistance test on
the driver and finals as per the readings in the manual and they
were all good.
Band? ?T9 out Power out
80? ? ? ?35V? ? ?130 W @ 0.4 amps
40? ? ? ?28V? ? ? ?90 W @ 0.375 amps
20? ? ? ?27V? ? ? 100 W @ 0.5 amps
15? ? ? ?35V? ? ? ? 30 W? @ 0.25 amps
10-1? ?30V? ? ? ? ? 5 W? @ 0.2 amps
10-2? ?30V? ? ? ? ? 5 W? @ 0.2 amps
10-3? ?30V? ? ? ? ? 5 W? @ 0.2 amps
There may have been some de-tuning from the scope probe in
the circuit, I get about 25 W output on 10 without the probe
there.?
I have checked and double checked all the fingers on the band
switch.?
What should I look at next? Some component is out of spec
somewhere.
Marcus PY2PLL