[R-390] Weird-ass PTO parts

[Tim Shoppa]

OK, I've been into the deep jungle of the PTO can and back out.

I understand at least a little bit the oddball caps inside the
can. I'm guessing that the big cylindrical one is some kind of
fixed vacuum cap, and that many of the others have special
tempcos.

But... what's with some of the weird componentry outside the can
but around the tube socket? As Barry was asking about, they've
got a tiny glass piston cap in the plate circuit, although it's
nominally detuned with a resistor to a very low Q. I associate
glass piston trimmers with VHF/UHF high-Q (or at least "as higha
of a Q as we can get") stuff, not with low-Q broadbandish type
stuff.

And then there's that bizarre waxed-up stack of ceramic bypass
caps.

Clearly really smart and experienced people, who understood
lots of complicated mechanical AND electrical compensation stuff,
made the PTO's. I'm not gonna try to second-guess what they put
inside the can at all. BUT... the weird combination of stuff
around the tube socket is just bizarre. Sort of like Gary Larson's
"Cow Tools" cartoon

 http://www.salon.com/people/portfolio/1999/12/21/larson/older4.html

I'm left trying to figure out the deep meaning and purpose of
these odd constructs. Any insights? (into either the PTO or cow tools,
that is!)

Tim.