In message . com, Tim
Shoppa writes
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.

I gave you a lot of places to look in my other post, but suddenly the
"Nothing at all" rings a very clear bell. Replace the driver, a
12BY7A, first before suspecting the finals, and especially if the bias
current in the finals is doing the right thing.

Tim.


If the TS530 is like the 520, one sign that the PA stage may need
neutralizing is that when, during tune-up, the maximum power output does
not coincide with the plate current dip. Another side-effect may be that
the receive pre-selector peak does not coincide with the transmit RF
drive peak.

If all seems more-or-less OK with the new tubes, you can probably leave
things alone.

However, if your 530 doesn't tune up at all, you'll need to look for
more than neutralizing (as suggested by Tim).
--
Ian