My TR-3 has recently had a decline in output. When tuned for max output on a
Bird Power meter, Plate Current is about 300mA, and output is about 115 Watts
on 80, 40 and 20 CW tune-up. It used to be able to tune up to 450 mA Plate
Current. On an Eico 667 tube tester, all final tubes (12JB6) appear to have
reasonable emission (one is a little less than the other two, but comparing to
another set, they are all a little light). I substituted a different 12BY7
driver with no difference. I also substituted some sylvania 12JB6 final
tubes for the RCA’s that were originally in the transceiver, and got about the
same output, although tuning up was a little difficult. I noted a label in the
radio stating that substituting a different brand of final tubes necessitates
realignment, and before I get into that I would want to know if that just
entails the adjustment of C76, and if it would be worth trying the sylvania
tubes and realigning to see if that improves the output.
I wonder what to look for next?
Thanks, George K9AAL
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