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I've added a circuit to supply the screen bias needed for a 12LP4, that uses the existing 170VDC supply and a 135 V. rms tap. It comes out to 255 VDC which is really close to the 250 v typical G2 operating point of the 12LP4.
After replacing the crt connector and adding the circuit I tried operating it with the 10MP4 to make sure I didn't mess anything up. It works fine. In fact, I used to have a minor problem with a crawling horizontal and vertical distortion in the image that I had thought was from the damper tube filament transformer which is mounted near the neck of the CRT. This problem has disappeared. So has the sync buzz you get when tuning, or have text displayed on the screen. In fact the sound quality is dramatically better.
There is no reason the circuit I added should have any effect on either the sweep or the sound. Guess I shouldn't complain though.
The next step will be to try the 12LP4. I'll take photos of the circuit addition when I do the test.
I got rid of my old rear projection set and mounted a DLP on the wall leaving space under it for the Sylvania console. I've attached a photo of how it'll be set up. The cabinet is empty at this point.
John
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