Date : Mon, 25 Aug 2003 09:37:34 +0100
From : Mike Tomlinson <mike@...>
Subject: Re: Monitor colour guns misaligned
In article <030814135502@...>, Jonathan Graham Harston
<jgh@...> writes
>Can anybody give me advice on how to realign the colours on a couple of my
>monitors?
Basically, you don't want to do it. Read on for why.
> They are Microvitec Cubs in a Torch cheese-wedge enclosure. The
>Red, Green and Blue colours no longer align with each other, giving very
>strange colour effects.
Has the Torch been dropped?
With power to the Torch disconnected and the lid off, look at the
magnetic ring assembly on the neck of the tube between the yoke and the
tube base PCB. There should be a painted stripe, usually white or
yellow, across the top of the rings. This is applied at the tube
factory after convergence has been performed to prevent the magnets
moving. Is the paint intact? If not, then the purity and convergence
controls have been disturbed, causing the effect you see. The magnets
are interdependent and altering one magnet to correct a visual defect
can cause a different defect to appear. Getting the adjustment right is
something of an art and should not be attempted by someone who has not
previously worked in monitor or TV repair. In addition, monitors
contain lethal voltage at lethal currents, some of which can remain
present for a long time after power is removed.
If, as I suspect, the factory-applied painted stripe is intact, the
probability is that the tube has gone 'soft' (worn out), in which case
it needs replacement. No amount of twiddling with the magnets will
help. It might be possible to rejuvenate the tube using a specialist
tube rejuvenator - a TV shop or monitor repair place can do this for you
but the improvement obtained is usually temporary and sometimes the
rejuvenation process can kill the tube outright.
If you can take a picture of the visual defect you describe, along with
some images of text in Mode 7 and Mode 0 and post those on a website, I
may be able to suggest whether the fault is misconvergence or a worn
tube.
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