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Old 06-18-2008, 04:25 PM
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mattdavala mattdavala is offline
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Join Date: Jun 2007
Location: Hillsboro, Oregon
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Quote:
Originally Posted by electroking View Post
What do you call 'static focus'? According to my RCA RC-29 Tube Manual
(1973), all B&W CRTs listed have either Electrostatic focus (a grid that
you connect to the correct potential, sometimes with taps, sometimes
with a potentiometer) or Magnetic focus (a focus coil). The only two
tubes that list a different focusing method (Automatic) are two test
tubes (8XP4 and 8YP4).

My two TVs, from 1956 and 1960, use electrostatic focus tubes
(21ALP4A, 90 deg. and 21DEP4, 110 deg.).

Regards.
Here is where my lack of electrical knowledge is going to kick me in the butt. I thought electrostatic focus was from a focus coil, and a static focus was using an adjustable PM maginet around the neck of the tube.

Now that I have thought of it my 66 color roundie uses a grid in the tube for focus. Electrostatic. My 21 inch B/W uses a focus coil, and my other B/w TV uses a PM maginet for focus.

Someone help me get my ideas straight here!
Thanks!!
Matt Davala
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