I haven't been following this thread but here are my comments based on the
attached messages. You may have difficulty finding a service technician who
knows how to adjust purity and convergence on a CRT. In about 1975 they
started coming from the factory with deflection yokes installed and all
purity and convergence adjusted.
Regards.
Max. K 4 O D S.
Email: [email protected]
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----- Original Message -----
From: "Arnold Tibus" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Saturday, April 17, 2010 7:04 AM
Subject: Re: [time-nuts] [OT] degaussing
The dotpitch of Trinitron and Diamondtron tubes (Mitsubishi)
is at 1/100 inch (0.24 mm to 0.27 mm), which defines the distance
of these shadow wires. What tube width do you have? ;-)
The wires are very sensitive to vibrations which makes the horizontal
stabilizing wires necessary (in most cases 2, max. 3). These are visible
with a bright and uniform picture.
All such tubes are equipped with a degaussing system
(electromagnetic coil in a black hose) which are normally activated
always when switching the monitor/ TV on. There is normally no
forther degaussing needed.
One can apply stronger magnetic fields from the front side by using
cannibalized coils in parallel with an adequate 50/ 60 Hz system
stepping the field continuously down. Attention, strong dc H- fields
may result in sticking some wires together, which may be very
difficult to get it corrected!
The small magnets on the back of the tube are necessary to
linearize the dynamic field of the deflecting coil and to compensate
other small steady magnetic distortions around the tube.
There are some more magnets on the neck of the tube for
convergence and beam forming.
A long and distracting work to to when you had to replace the tube
or coils and then to adjust for white and clean colors and sharp
picture...%-))
Older systems needed an earth field compensation in situ.
(Don't try it when you are not experienced with it, you will turn crazy -
and the professional serviceman later will as well!)
greetings,
Arnold
On Fri, 16 Apr 2010 21:05:31 EDT, [email protected] wrote:
point of trivia:
can you count how many vertical wires are strung across a Trinitron
monitors' shadow mask??
I used to work at Sony for a long time, we had a TV assembly line next
door
:)
If you can see the vertical wires, you still have very good eyesight...
bye,
Said
In a message dated 4/16/2010 04:55:35 Pacific Daylight Time,
[email protected] writes:
Are they really? For some reason, every Trinitron I have ever seen
has clusters of little stick on magnets placed here and there on the
back of the glass envelope.
The trinitron has a shadowmask. It is a grill of highly tensioned wires
that are positioned just behind the screen. The original trinitron tube
was a little 5 inch diagonal CRT. It had to be small because the wires
tended to vibrate if the set was bumped, and that made for some very odd
displays. The later larger tubes had horizontal titanium wires welded to
the backs of the shadow mask wires every 5 or 10 inches, to prevent the
psychedelic color fest that happened when the CRT got bumped.
The trinitron has three very carefully aligned cathodes in the gun. They
are positioned side-by-side, creating the slight different projection
angles necessary to cause the long vertical slots formed by the shadow
mask
to eclipse the appropriate color bands on the screen.
I'm not sure what you are describing; it sure sounds cool; but it isn't
a trinitron.
Can you find some references? I'd like to read up on it.
-Chuck Harris
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