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Old 06-26-2010, 10:22 PM
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Dave A Dave A is offline
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The Indextron was a Sony name for a variant of the Philco Apple beam-index CRT color picture tube from the late 50's that Philco gave up on. Sony ended up with the patent. It was a Watchman-sized SS set at 3.5" or so.

It had no shadow mask and relied on a rear-mounted photocell to track the single-gun beam crossing the vertical phosphor stripes, switching color at each stripe. The photocell monitored the beam position and made the color change as the sweep went on.

Each stripe was separated by a black stripe to prevent cross-color contamination and allowing the clean switch during the black stripe. IE, the beam hitting the red and overlapping in to the green.

Red/black/green/black/blue/black and so on. The beam focus is the most critical to prevent overlap in to the next stripe and illuminating two stripes. Red plus green = yellow, etc.

The big problem was that 25% or so of the screen was black stripes and diminished the brightness. No shadow mask should be a bonus but the black stripe killed any gain. Aside from that problem, it does make a very sharp picture. The other big Sony problem was cheap surface caps. Mine needed around 20 or so replaced to make it operative. This one needs the full re-cap.

Sony only made it for a while in 1988. Most are dead and only a handful have shown up. This is the first white cabinet seen by me.
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Last edited by Dave A; 06-26-2010 at 10:27 PM.
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