[TenTec] Model 540 questions

[Louis Ciotti]

So as the weather has been getting colder I have been starting to play
on HF.  I have an old TenTec Model 540.  It has developed a few issues
as of late.  First I have low output on 80meters.  All other bands I
get the full 100 watts, 80 I get about 40.  Any thoughts??  Also when
I 80, the frequency display (external one) is not stable.  The last
question I have is any thought on adjusting the "resonate" dial?  I
see two screws that look like they can adjust the frequencies.

Thanks,
Lou
K2LRV