Can a monitor's built in degaussing coil make it worse?
 

Hi,

I have a computer monitor that is mounted almost on its back, but at a
slight 15 degree angle. It is in an arcade cabinet. The built in
degaussing circuit does a pretty good job, but there is still an impurity in
the red in the lower left corner and in green along the right edge. I used
a degaussing coil which reduced the impurity, but after turning the monitor
off and on which activates its internal degaussing coil, it seems to make
the impurity worse. Is this normal? Could it be something with the way
they have the internal coil routed around the tube? Is there another
adjustment for changing the monitor's orientation this much I should look
at?

Thanks,

Alan

I don't suppose there is any sort of magnetic field nearby - speakers etc?
It could also possibly be a tube fault.

"SA Development" wrote in message
...
Hi,

I have a computer monitor that is mounted almost on its back, but at a
slight 15 degree angle. It is in an arcade cabinet. The built in
degaussing circuit does a pretty good job, but there is still an impurity
in
the red in the lower left corner and in green along the right edge. I
used
a degaussing coil which reduced the impurity, but after turning the
monitor
off and on which activates its internal degaussing coil, it seems to make
the impurity worse. Is this normal? Could it be something with the way
they have the internal coil routed around the tube? Is there another
adjustment for changing the monitor's orientation this much I should look
at?

Thanks,

Alan

"SA Development" writes:

Hi,

I have a computer monitor that is mounted almost on its back, but at a
slight 15 degree angle. It is in an arcade cabinet. The built in
degaussing circuit does a pretty good job, but there is still an impurity in
the red in the lower left corner and in green along the right edge. I used
a degaussing coil which reduced the impurity, but after turning the monitor
off and on which activates its internal degaussing coil, it seems to make
the impurity worse. Is this normal? Could it be something with the way
they have the internal coil routed around the tube? Is there another
adjustment for changing the monitor's orientation this much I should look
at?

While something mangetic in the vicinity is the most likely cause as
suggested in another posting, note that monitors are adjusted assumgint
they will be used in the normal orientation. When tilted as far as
you have it, the Earth's magnetic field direction is significantly
different than normal.

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Hi,

While something mangetic in the vicinity is the most likely cause as
suggested in another posting, note that monitors are adjusted assumgint
they will be used in the normal orientation. When tilted as far as
you have it, the Earth's magnetic field direction is significantly
different than normal.

I'm pretty sure it isn't something magnetic because I had a different
monitor in it that didn't have this issue.

What do you guys think about my theory that the built in degauss coil is
actually messing it back up slightly? I haven't proven it yet, but the
manual degauss coil seems to make it look pretty good and then when I turn
the monitor back on the internal coil seems to mess it up a little more. I
haven't tried rotating it 180 degrees to see if it works better in that
orientation yet, I might give that a shot too. Any other ideas?

Thanks,

Alan

SA Development wrote:
Hi,


While something mangetic in the vicinity is the most likely cause as
suggested in another posting, note that monitors are adjusted assumgint
they will be used in the normal orientation. When tilted as far as
you have it, the Earth's magnetic field direction is significantly
different than normal.


I'm pretty sure it isn't something magnetic because I had a different
monitor in it that didn't have this issue.

What do you guys think about my theory that the built in degauss coil is
actually messing it back up slightly? I haven't proven it yet, but the
manual degauss coil seems to make it look pretty good and then when I turn
the monitor back on the internal coil seems to mess it up a little more. I
haven't tried rotating it 180 degrees to see if it works better in that
orientation yet, I might give that a shot too. Any other ideas?

Thanks,

Alan

Hi Alan...

If you mentioned the age of the setup I musta missed it...
but is it possible that the monitor is old enough that it
requires purity setup?

Us really old guys will recall the days when the yoke wasn't
cemented to the tube... used to loosen a setscrew, slide the
yoke back on the neck of the tube. Find a red blob, center it
with centering magnets, "purify" it with yet another magnet,
then slide the yoke back as close to the bell as you could
without upsetting purity.

All behind the set, while holding a mirror in one hand around
the front so you could see what was happening. And hoping not
to grab the yoke itself :) And then came convergence...:)

Ahhh, the good old days :)

Ken

"SA Development" wrote in message
...
Hi,

While something mangetic in the vicinity is the most likely cause as
suggested in another posting, note that monitors are adjusted assumgint
they will be used in the normal orientation. When tilted as far as
you have it, the Earth's magnetic field direction is significantly
different than normal.

I'm pretty sure it isn't something magnetic because I had a different
monitor in it that didn't have this issue.

What do you guys think about my theory that the built in degauss coil is
actually messing it back up slightly? I haven't proven it yet, but the
manual degauss coil seems to make it look pretty good and then when I turn
the monitor back on the internal coil seems to mess it up a little more.
I
haven't tried rotating it 180 degrees to see if it works better in that
orientation yet, I might give that a shot too. Any other ideas?

Thanks,

Alan



You probably magnetized it slightly with the external coil and "fixed" the
misadjustment, then the internal degaussing coil demagnetized it so it's
messed up again.

Hi,

Thanks everyone for the comments and ideas. I ended up rotating it 180 deg
and this made it much better. So now instead of the bottom of it to the
left I have the bottom of it to the right. I degaussed it with the external
coil, then with the monitors internal degauss feature. I can still see a
very slight discoloration of the red in the upper left, but nothing like it
was before and hardly noticable.

Thanks,

Alan

On Wed, 16 Mar 2005 16:18:01 -0600, "SA Development"
put finger to keyboard and composed:

Hi,

I have a computer monitor that is mounted almost on its back, but at a
slight 15 degree angle. It is in an arcade cabinet. The built in
degaussing circuit does a pretty good job, but there is still an impurity in
the red in the lower left corner and in green along the right edge. I used
a degaussing coil which reduced the impurity, but after turning the monitor
off and on which activates its internal degaussing coil, it seems to make
the impurity worse. Is this normal? Could it be something with the way
they have the internal coil routed around the tube? Is there another
adjustment for changing the monitor's orientation this much I should look
at?

Thanks,

Alan

Did you experiment by disconnecting the degaussing coil?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Hi Franc,

Did you experiment by disconnecting the degaussing coil?

I never tried that, but it was on my list to try. Oddly enough rotating the
monitor 180 degrees so the bottom was to the right instead of the left
seemed to clear it up.

Thanks!

SA Dev

When a CRT monitor is orientated to outside of the paramter of
calibrateon, such as not lying flat as it should, it is very likely
that the earth's magnetic field is effecting the mask of the CRT. If
you orientate the monitor to be flat, it is most likely it will be
working okay.

Jerry G.
======

"SA Development" wrote in message
...
Hi,

Thanks everyone for the comments and ideas. I ended up rotating it 180
deg
and this made it much better. So now instead of the bottom of it to the
left I have the bottom of it to the right. I degaussed it with the
external
coil, then with the monitors internal degauss feature. I can still see a
very slight discoloration of the red in the upper left, but nothing like
it
was before and hardly noticable.

Thanks,

Alan



Are you sure it doesn't have a purity adjustment in the menus? Many computer
monitors do, particularly larger ones.

Failing that, strategic gluing of a few small refrigerator magnets can cure
it.

On Thu, 17 Mar 2005 03:07:51 GMT, Ken Weitzel
wrote:



SA Development wrote:
Hi,


While something mangetic in the vicinity is the most likely cause as
suggested in another posting, note that monitors are adjusted assumgint
they will be used in the normal orientation. When tilted as far as
you have it, the Earth's magnetic field direction is significantly
different than normal.


I'm pretty sure it isn't something magnetic because I had a different
monitor in it that didn't have this issue.

What do you guys think about my theory that the built in degauss coil is
actually messing it back up slightly? I haven't proven it yet, but the
manual degauss coil seems to make it look pretty good and then when I turn
the monitor back on the internal coil seems to mess it up a little more. I
haven't tried rotating it 180 degrees to see if it works better in that
orientation yet, I might give that a shot too. Any other ideas?

Thanks,

Alan

Hi Alan...

If you mentioned the age of the setup I musta missed it...
but is it possible that the monitor is old enough that it
requires purity setup?

Us really old guys will recall the days when the yoke wasn't
cemented to the tube... used to loosen a setscrew, slide the
yoke back on the neck of the tube. Find a red blob, center it
with centering magnets, "purify" it with yet another magnet,
then slide the yoke back as close to the bell as you could
without upsetting purity.

All behind the set, while holding a mirror in one hand around
the front so you could see what was happening. And hoping not
to grab the yoke itself :) And then came convergence...:)

Ahhh, the good old days :)

Ken

I can recall those days, I grew up working in my old mans repair shop
back in the 50's.
The solution to setting the yoke was not to try and use a hand held
mirror.
Pops had one whole wall of his shop set up with a real big mirror,
then all the techs had to do was point the front of the tv to it.

Heck I can remember when work was slow he's bring over boxes of odd
parts from just about every brand and tell me to build a working
set.(couldn't do that today tho'.)