monitor with screwed colour in bottom-right of screen

From: <(>
Date: Fri Mar 12 13:36:43 2004

> This is fixable. It is caused when some material is
> magnetized. The process to fix it is called
> 'demagnetizing'. The theory is simple: You apply a
> changin magnetic field (for example, that created by a
> coil with 60Hz AC), and graduately decrease the
> strength of the magnetic field (for example, you pull
> the coil further away from the monitor while moving it
> in circle). It will fix the problem. Some monitor or
> TV has build in circuit to perform the process.

> In my experience, this is a lot trickier than it sounds. I would
> first practice on a CRT that you aren't fond of before moving on to
> the one you're trying to rehabilitate.

Coils for CRTs are wrapped in electrical tape and shaped to suit to
hug the CRT. Electrical tape they used can be any color, rarely see
one with off the beaten trail color like yellow, blue etc.

In tritron CRT monitors especially high end, it has many coils around
the back of CRT, one is degaussing, at least 2 thinner coils for
purity compensation, one round coil near CRT yoke for
picture rotation (common to many monitors also found in some direct
view TVs.)

Sounds like the purity compensation circuit isn't working, check that
your monitor compass module is working. Yes there are few monitors
has one uses it for automatic purity adjustments when monitor is
facing in different direction.

How I know? Fixed an high end sony 21" monitor with that feature.
It was bad compass module IC, more precise, a pin corroded off, fixed
that by grinding away black package and solder short strand of to
make connection. Compass module board is usually horizontal and
almost centered where the base axis is.



Sellam Ismail                                        Vintage Computer Festival
Received on Fri Mar 12 2004 - 13:36:43 GMT

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