OK, whether the field is retiring me or the other way around is
irrelevent. But I have been pretty much the foremost expert on three
tube PTVs in at least this state for some time. Of course you see that
is not exactly the hottest job in town. I am not saying that I am THE
expert on everything, but what makes a CRT RPTV work, as opposed to a
direct view, that has been my specialty. In fact if I went to work on
direct views I would probably have to work for ten bucks an hour.

But I get into theory and this thread is for folks like that. I know
what it takes to make those things work, I have worked damnear
miracles on them, but I never designed them. I have done some repairs
so serious that I guess I could claim I can build one, but I still
never designed one.

A couple months ago I ran into one of those Hitachis with the necked
down neck. I mean where the yoke goes the neck is narrower, which
means the yoke is manufactured on the tube and is TRULY a bonded yoke.
Not just glued like before.

They did this of course to get the coils closer to the beam, which
increases deflection efficiency. So one can only assume that the power
consumed by the deflection circuit was an issue to be addressed. Since
I am a million years old I remember when the old delta gun CRTs went
out and the inline guns came in, and then smaller and smaller necks.
Inverse square folks, the closer the better.

Now MY question :

Why the hell didn't they just go with electrostatic deflection like in
a scope ?

Think about it, you people out there who know engineering, think about
it. Why not ? I understand about the CRT parameters and the variance
with beam current and I also know about beam density. I know these are
all problems, but using magnetic deflection solved none of them !

THINK THINK about that.

OK, I am not an idiot, I KNOW why a color CRT whether it is delta or
inline gun, would not benefit from electrostatic deflection. But I see
no disadvantabe when it comes to a monochrome CRT, which is what the
scope was. And what the PTV was as well.

You can use magnetic deflection for a scope, it's just that the
results suck. Bandwidth and all that. But in a three tube PTV that
flexibility in the deflection would be so much more efficient. You got
horizontal, vertical, and SIX channels of amps running sub yokes. I
thought the wattage race had already started. This would have won.

But I am also not stupid. If they could be more efficient it would
have been a selling point. No STKs, small transistors work into the IE
capacitance of the plates. That's all. You could concievably have the
impossible (OK I know osmeone will find one), the old never happen CRT
based 1080p TV.

The reason you can't have a CRT at 1080p is because of the inductance
of the yoke. You would have to stick a four thousand volt pulse to
it.

But you do not have that problem with deflection plates, rather than
coils.

In the end, what seems to elude me is why they did not persue
electrostatic deflection for three tube PTVs. they have all the
halation and every other thing figured out, tracking HV/focus levels
and all that already.

Or did they just want to sell yokes ? :-)

J