[Gllug] OT: recommend place to buy 17" tft monitor

[Chris Bell]

On Tue 14 Dec, Nix wrote:
> 
> On Mon, 13 Dec 2004, Chris Bell stipulated:
> >> But it was only a guess --- and anyway, it got replaced with no
> >> difficulty.
> >> 
> >    That just sounds like a degauss circuit fault. It is usually a simple
> > brute force circuit with temperature dependant resistors to deliberately
> > allow a short pulse of mains to the coil round the edge of the screen, and
> > at the same time slowly increase mains volts to the rest of the power
> > supply.
> 
> So it was as if I was constantly degaussing?

   The temperature dependant resistors can just fall apart after a while.
> 
> Note that the colour bands were *linear*; does the degauss circuit run along
> the top and bottom of the screen or something?

   It is a few turns of wire taped together and wedged in place all round
the outside of the tube close to the edge of the mask. The tube may be a
shadow mask with round holes and the electron guns in a triangle at the back
end, or a "trinitron" type with vertical wires, held in place by horizontal
wires at about 1/3 and 2/3 of full height, with three electron guns in a
horizontal line at the back. The tube phosphors are positioned optically,
with light sources held where the guns will be fitted later, using a process
similar to that used for the manufacture of printed circuits.

> 
> (I suspected the shadow mask because of the bands of greyness running
> across the screen at *exactly* the places where the shadow mask mounting
> wire things normally run.) 
> 
> >    At one time a normal requirement at work was that you should be able
> > stand on anything, and stack gear in a lorry up to about shoulder high, but
> > then someone decided that it was cheaper to buy more off-the-shelf
> > "domestic" kit and replace the bits that fell off.
> 
> Alas, it's often the consumers who have to do the paying :(
> 
> >                                                   I have seen monitors
> > dropped without damage to the tube while the case
is shattered,
> 
> *BOGGLE* Who'd have guessed that a glass tube was stronger than plastic?
> 
   The front of the tube is very thick, strong, and heavy, and must provide
safety protection. Older tubes sometimes failed, and the internal vacuum
could throw the gun assembly through the front. Large tubes are very heavy,
and the EHT connection point recharges itself as the glass slowly relaxes.
It is too easy to receive a very nasty shock approaching 25,000 volts while
carrying an old tube, and it is dangerous to just let go and drop it.

-- 
Chris Bell

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