CRT monitor acting like an LCD !?

[(Just) Allan]

I have a 21" Dell CRT monitor. About a third of the way from the top
of the screen there is a horizontal line - just like you see when an
entire line of pixels fails on an LCD monitor. It's only very faint
at the moment. The line is dead still (doesn't roll with the refresh
rate) and it is (obviously) more noticeable when the screen is white
or the white mouse pointer is positioned so the line passes through
it.

What would cause this kind of fault !?

Allan.

 

[Wayne]

I have a 21" Dell CRT monitor. About a third of the way from the top
of the screen there is a horizontal line - just like you see when an
entire line of pixels fails on an LCD monitor. It's only very faint
at the moment. The line is dead still (doesn't roll with the refresh
rate) and it is (obviously) more noticeable when the screen is white
or the white mouse pointer is positioned so the line passes through
it.

What would cause this kind of fault !?

Allan.

HI, you will find there is also a horizontal 'line' about a third of
the way from the bottom. These are support wires for the aperture
grill. All Sony Trinitron CRT monitors have these 'lines'.

From a Google search...


Why do Trinitron monitors have one or two thin lines stretching across
the width of the screen?

A single 'damper wire' (or two wires for bigger screen
monitors) is placed horizontally across the vertical stripes of the
Trinitron Aperture Grille. This holds the grille in place and limits
possible vibration. Generally, the line is not visible, although it
may be seen against a white background.

Wayne

 

[Mitchell McCreath]

I have a 21" Dell CRT monitor. About a third of the way from the top
of the screen there is a horizontal line - just like you see when an
entire line of pixels fails on an LCD monitor. It's only very faint
at the moment. The line is dead still (doesn't roll with the refresh
rate) and it is (obviously) more noticeable when the screen is white
or the white mouse pointer is positioned so the line passes through
it.

What would cause this kind of fault !?

Allan.

Thats normal for a Sony tube. My HP Monitor Has them as well...

Regards,
Mitchell

 

[(Just) Allan]

Let me guess, you also have one about 1/3 of the way from the bottom as
well. If so, you have a Trinitron monitor. It's just how they are
made. There are two thin wires suspending the shadow mask behind the
glass. They show up as thin, slightly darker horizontal lines. I like
to point these out to people that have never noticed them before.

Yep, you're both right - I bought a new system and had the choice of a
17" LCD for ~$450, but then saw the secondhand 21" Dell CRT for um...
$180 I think it was. I'm *sure* the lines weren't there for an entire
week. I only noticed the second line after posting the message. It
just made no sense (surely the line should move or oscillate in SOME
way!?)

I wonder if they all have this - probably not I guess, or they
wouldn't have sold many.

Allan.

 

[Ray]

a dark line and not a gap?


I had a gap on my screen caused by the magnetic field of the monitor beside
it which was running at the same vertical sync rate.

If it's a used monitor it could be burn in.

Bye.
Jasen

I suggest you research Trinitron monitors and you will find the answer
lies within - hint "shadow line".

Ray

 

[(Just) Allan]

Thats normal for a Sony tube. My HP Monitor Has them as well...

Regards,
Mitchell

As long as it's not a real fault, I'm happy I guess. I don't suppose
there's a way to minimise it at all? (I own a degaussing wand - don't
suppose it would do much.) I wonder if the wire becomes more visible
over time because of corrosion/contamination.

 

[(Just) Allan]

I had a gap on my screen caused by the magnetic field of the monitor beside
it which was running at the same vertical sync rate.

Yeah, I turned off the other one - although I thought it could still
be induction - but the other guys are right - there are two lines, so
it sound like they nailed it.

 

[Michael C]

I wonder if they all have this - probably not I guess, or they
wouldn't have sold many.

They are all like this, have been for many years and they've sold plenty.
You don't notice them unless you are looking for them. I'd completely
forgotten about mine and hadn't noticed them for a year until you reminded
me. Thanks a lot ;-)

Michael

 

[atec]

As long as it's not a real fault, I'm happy I guess. I don't suppose
there's a way to minimise it at all? (I own a degaussing wand - don't
suppose it would do much.) I wonder if the wire becomes more visible
over time because of corrosion/contamination.

I have two digital 21" and an IBM 21" on the desk . all share the same
tube as yours and all have the lines . use a darker background and
forget it .

 

[Tom Smyth]

See if there is another one about a third from the bottom.
I think there wil be one.

DELL, I beleive use SONY trinitron tubes and this is normal. What you see
is "support for shadow mask". This is how Trinitrons ara made.

You're kidding? Mine has that. I thought I inherited a piece of junk.

In it's day it was a professional quality monitor with Trinitron tube. And
it is supposed to have faint lines across the screen?

Also I can't get the image square using the OSD, and apparently there is no
service mode.

 

[Rudolf]

Look up Trinitron on the Internet. This will explain why you have the lines.

Realistically, working with monitor like that you will stop noticing them
very quickly.

As for getting picture square, there should be adjustments for it. Some
monitors have service mode, some have service port and you need special
hardware/software to access it. Some have internal pots. Most SONYs had the
service port, so only SONY service center can help you there. When I had
SONY for repairs and they needed asjustments I usually soldered in couple of
resistors.

Rudolf

 

[GB]

Realistically, working with monitor like that you will stop noticing
them very quickly.

I had never noticed the lines in the big Trinitron that I work with
every day, until a friend said "Ahh, Trinitron, yes, once I point out
those two black lines to you, you'll never be able to ignore them
again!".

I could have killed her right there and then!


GB