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On Sunday, 31 December 2017 13:55:06 UTC, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

A B&W TV can't show colour - other than that of its phosphor.
Assuming
you are talking old CRT sets

Early CRT TVs were known to produce a pink picture when the EHT
partially shorted, causing the current limiting red lamp to light
behind
the CRT.

How early are you talking about? I've never heard of that one.

First generation CRT sets used a mains transformer to provide EHT for the
CRT.

I presume this was a transformer that had mains on the primary and EHT on
the secondary, needing only a rectifier and smoothing circuitry to give the
EHT for the tube, whereas modern CRTs used a relatively low voltage (maybe
mains), that was rectified and then multiplied by a ladder
rectifier/capacitor stack so the full EHT was achieved after several mains
cycles - one to charge each capacitor in the ladder.

A red pygmy lamp was fitted in series with the mains side for short
protection. There's an old story out there about a woman that phoned Ally
Pally to congratulate them on the lovely shades of red & pink in the
picture only to be told she should switch it off before it caught fire.

The EHT was deadly on these sets.

Isn't EHT *always* deadly? If a current-limiting resistor was fitted to
reduce the severity of an electric shock from the several thousand volts of
EHT, wouldn't it prevent enough current flowing to drive the CRT?