My CRT monitor has suddenly developed a color blotch in the upper left
corner. It turns blues green, turns greens red, turns reds blue, and
turns yellows and oranges purple.
I'm pretty sure there's nothing magnetic nearby. And nothing around
the monitor has changed that I know of.
It's a 22" Mitsubishi Diamond Plus 200.
Does this mean the monitor is dying? I assume any professional repair
would exceed the replacement cost. Is there anything I can do myself?
>My CRT monitor has suddenly developed a color blotch in the upper left
>corner. It turns blues green, turns greens red, turns reds blue, and
>turns yellows and oranges purple.
>
>I'm pretty sure there's nothing magnetic nearby. And nothing around
>the monitor has changed that I know of.
>
>It's a 22" Mitsubishi Diamond Plus 200.
>
>Does this mean the monitor is dying? I assume any professional repair
>would exceed the replacement cost. Is there anything I can do myself?
That has all the characteristics of a magnetic effect. These can last a looong
time after the magnet has been removed - we had one comedian wave a strong
magnet near a monitor and it was *******.
Greg Lovern wrote:
> My CRT monitor has suddenly developed a color blotch in the upper left
> corner. It turns blues green, turns greens red, turns reds blue, and
> turns yellows and oranges purple.
>
> I'm pretty sure there's nothing magnetic nearby. And nothing around
> the monitor has changed that I know of.
>
> It's a 22" Mitsubishi Diamond Plus 200.
>
> Does this mean the monitor is dying? I assume any professional repair
> would exceed the replacement cost. Is there anything I can do myself?
>
> Thanks for any suggestions.
>
> Greg
Degauss? The monitor may have a built-in degausser...
On Apr 15, 5:57*am, Ofnuts <o.f.n.u....@la.poste.net> wrote:
> Greg Lovern wrote:
> > My CRT monitor has suddenly developed a color blotch in the upper left
> > corner. It turns blues green, turns greens red, turns reds blue, and
> > turns yellows and oranges purple.
>
> > I'm pretty sure there's nothing magnetic nearby. And nothing around
> > the monitor has changed that I know of.
>
> > It's a 22" Mitsubishi Diamond Plus 200.
>
> > Does this mean the monitor is dying? I assume any professional repair
> > would exceed the replacement cost. Is there anything I can do myself?
>
> > Thanks for any suggestions.
>
> > Greg
>
> Degauss? The monitor may have a built-in degausser...- Hide quoted text -
>
> - Show quoted text -
Degauss makes it look right for a second or so, then I hear a second
click and the blotch reappears.
Greg Lovern wrote:
> On Apr 15, 5:57 am, Ofnuts <o.f.n.u....@la.poste.net> wrote:
>> Greg Lovern wrote:
>>> My CRT monitor has suddenly developed a color blotch in the upper left
>>> corner. It turns blues green, turns greens red, turns reds blue, and
>>> turns yellows and oranges purple.
>>> I'm pretty sure there's nothing magnetic nearby. And nothing around
>>> the monitor has changed that I know of.
>>> It's a 22" Mitsubishi Diamond Plus 200.
>>> Does this mean the monitor is dying? I assume any professional repair
>>> would exceed the replacement cost. Is there anything I can do myself?
>>> Thanks for any suggestions.
>>> Greg
>> Degauss? The monitor may have a built-in degausser...- Hide quoted text -
>>
>> - Show quoted text -
>
> Degauss makes it look right for a second or so, then I hear a second
> click and the blotch reappears.
>
> Greg
One of those 'quick' heat' soldering guns will do the trick, the one with a trigger on them that looks like a gun. They produce heat in the the U shape tip by 'eddy currents' from the electromagnet.... it is this we utilize here, a normal type soldering iron will not work.
Switching the gun on a couple of feet away, and slowly approach the screen with a picture displayed moving the iron slowly near the TV screen waving it in a circular motion over the entire screen, then moving slowly away before switching off. We have to use it side on.... not the tip as we want to use it's magnetic field - this only works on CRTs BTW.
As per previous post this could is caused by magnetic fields, usually one cuplrit is hi-fi speakers close to the set... but more often than not its caused by a degaussing posistor (not a thermistor - a posistor is two thermistors, a positive and a negative one combined).
The action is when you switch the set on it's 'stone cold' and the resistance low, and when cold they allow a large current to flow in the degauss coil around the tube, thus demagnetizing the shadowmask, within a few seconds the thing heats up the resistance increases and stops the current flow, it remains hot until you turn the set off. Sometimes the element inside the posistor cracks.... and there's the problem - no degauss and a magnetized shadowmask in the tube and a load of pretty blotches.
One good way to check these, when taken out is to shake them if it rattles like Mick Jaggers marraccas you know it's faulty.
>more often than
>not its caused by a degaussing posistor (not a thermistor - a posistor
>is two thermistors, a positive and a negative one combined).
>
>The action is when you switch the set on it's 'stone cold' and the
>resistance low, and when cold they allow a large current to flow in the
>degauss coil around the tube, thus demagnetizing the shadowmask, within
>a few seconds the thing heats up the resistance increases and stops the
>current flow, it remains hot until you turn the set off. Sometimes the
>element inside the posistor cracks.... and there's the problem - no
>degauss and a magnetized shadowmask in the tube and a load of pretty
>blotches.
Well, you should be able to hear if the degauss is working or not...
See it as well, if you turn the monitor off, and then quickly back on
while it's still warm - the whole screen should go berserk for a time.
And do modern CRT monitors work the way you describe? My Mitsubishi
here does not - it obviously uses a relay to disengage the degauss
current after several seconds.
CRT color blotch 
Linear Mode
