22 May
2012
22 May
'12
11:37 a.m.
Tony Duell wrote:
In-line gun CRTs (whether used i nTVs or monitors) rarely had an external
magnetic shield over the CRT flare, delta gun ones, again both TV and
monitor, often did. If you don't rememebr those, start fixing Philips
G8s, etc :-)
But I've heard this clang on in-line gun nonitors too. And there doesnt'
seem to thew that much metal near the degaussing coil to make any noice.
But maybe it is just the chassis flexing.
Yes, some monitors degauss with quite a lound
'clang' (I assume it's the
shaddowmask. flexing. I've never heard a TV that does that.
I think it's the thin steel internal screening can of a computer
monitor that makes the "clang". And the screening is something
that I don't think I've ever seen in a TV. Although, my Sony
widescreen CRT TV (FreeCycle) makes a slight twang sometimes
on power-up. Tony, do you remember that Tomorrow's World
programme when
Raymond Baxter showed us how to distort a TV picture with
No, I always had better things to do than watch TV.
a magnet? And the warnings on the next week's
episode
where they said "don't try this on a colour TV!". I think
they said that the producer had tried it on a colour set,
and it was OK, so they broadcast it -- without realising
that he'd been lucky, and a stronger magnet would do
bad things.
I do remewmebr articles, letters, etc in electronics magazines about it.
Maybe Everyday Electroncis (long befroe it merged with Practical
Electronics [1]) in the mid 1970s.
[1] I acutally took inspiration from a circuit in a 1972 issue of
Practical Electronics yesterday. I needed a simple distinctive
noise-maker and for various reasons I didn't want ot use any ICs. The
;Hooting Owl' in the December 1972 issue was a starting point. I got the
circuit down to 4 transistors, 7 resistors, 5 cvapacitors and a transducer.
-tony