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On Tuesday, 18 July 2017 21:42:52 UTC+1, John-Del wrote:
On Tuesday, July 18, 2017 at 1:37:35 PM UTC-4, Ian Field wrote:
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On Monday, July 17, 2017 at 2:25:37 PM UTC-5, Ian Field wrote:
jamesgmail.com wrote in message
news:1a527a6f-6b49-454e-8fa1-dd1f71088fc4googlegroups.com...

What is a PIL tube ?

May have been a copyright dodge to avoid the Trinitron.

Perhaps, but I think most of Sony's engineering efforts were to avoid
everyone else's patents. Their 70s power supply designs are a Rube
Goldberg's nightmare wrapped in a chain saw wielding mass murderer's warm
embrace. They weren't notably efficient or particularly well regulating,
so my guess is that they were building a unique design with no patents
(and really, who would patent such an abortion?).

I remember when NYC was reducing power during the 70s in an "energy
saving" attempt. Well Sony power supplies committed harakiri at not much
less than 100VAC, and lots of Trinitrons were blowing up during the
brown-outs.

The Trinitron when it worked right produced some fabulous images, but I
think the tube was very finicky and required far more stringent
manufacturing tolerances than the typical tube, hence the cost. Give it
a small nudge and the shadow mask would shift or one of the wires would
snap. Early tubes had the coaxial second anode connector and those tubes
would short internally.

Don't miss those days. (much)

I remember the PSU boards in 70s trinitron sets. Talk about unnecessarily
complex. As an experiment I once replaced the PSU board with a lightbulb
as a dropper. (I forget how I provided filament power.) It worked, though
voltage instability caused picture height instability.

I liked those sets as they were well valued but CRT emission tended to go.
No-one else had worked out how to get the emission back, I did.

With monitors - I discovered that some 'genius' at Philips had published a
bulletin stated that stable SMPSUs meant CRT heaters only needed 6.15V. Most
manufacturers fell for it, and most CRTs ended up with poisoned cathodes.

There was plenty of evidence that some engineers were just turning the wick
up in the PSU. My solution was to fit a Shottky-barrier heater rectifier,
that needed an added snubber to prevent the flyback peaks killing the
rectifier, and improvements to the filter circuit. Some already had Sb
rectifier, so there wasn't much I could do.