On Aug 13, 8:55 pm, "KB3IBT Dan K" wrote:
Oh, wow, thanks for the explanation Uncle Peter. I really appreciate it! I'm
gonna stick with new tubes. I hope my TS-530 will be able to tune up. Its
been sitting almost a year collectin dust next to my beloved TS-870.
I tried tuning the 530 this past Sunday and it wouldn't budge. Nothing at
all. It still receives pretty good.

It's not so obvious that a transmitter that doesn't "budge" obviously
needs new finals. If the last time the transmitter was used there was
a big puff of smoke from the final compartment and a lot of blue
flashing, maybe, but I've smoked far more plate chokes and HV coupling
or bypass caps than finals over the years.

Does it show any plate current at all? The finals are biased for AB1
or so and probably should draw 50 mA or so (see your manual for
details) when keyed up and no signal. If so, as you tweak the bias
(not sure where it is in a TS-530 but there must be a final bias pot)
does the current behave semi-linearly?

If you have bias which behaves right but no signal out, I'd suspect
something in the drivers, not the finals.

If you're sucking major current when there's no signal, then the tubes
might be gassy or maybe the screen current is out of whack or you've
got some super-nasty parasitics (which actually comes back to the
neutralization you asked about).

If the bias isn't behaving right, I'd suspect plate choke/bias
circuitry/screen supply/plate supply.

If it sucks current but fails to load up, then a bad coupling
capacitor or bad bandswitch or pi-network variables.

Tim.