PC monitor repair help

[Eric Goldsmith]

I have a Samsung 955DF monitor that's ~3 yrs old, and just out of
warranty.

After performing flawlessly until now, I've noticed that it drifts out
of focus, but only when it's displaying a lots of white.

For example, when viewing Web pages with white backgrounds, or
black-on-white MS-Word or Excel document, after about 5 minutes I
notice it loosing focus. After 20 minutes it's actually painful to
look at.

The odd thing is that this only occurs when there's large quantities
of white on the screen (i.e. backgrounds). I don't notice it with
other colors.

Also, it doesn't worsen just by virtue of how long the monitor has
been on - my initial thinking was that it was heat related (and easy
to troubleshoot with a can of freeze spray). It only starts happening
when the screen contains lots of white.

Thinking about it now, I'm wondering it this is really a focus
problem, or if the display is "blooming" over time.

At any rate, any ideas where to start looking for the problem?

Thanks

 

[petrus bitbyter]

I have a Samsung 955DF monitor that's ~3 yrs old, and just out of
warranty.

After performing flawlessly until now, I've noticed that it drifts out
of focus, but only when it's displaying a lots of white.

For example, when viewing Web pages with white backgrounds, or
black-on-white MS-Word or Excel document, after about 5 minutes I
notice it loosing focus. After 20 minutes it's actually painful to
look at.

The odd thing is that this only occurs when there's large quantities
of white on the screen (i.e. backgrounds). I don't notice it with
other colors.

Also, it doesn't worsen just by virtue of how long the monitor has
been on - my initial thinking was that it was heat related (and easy
to troubleshoot with a can of freeze spray). It only starts happening
when the screen contains lots of white.

Thinking about it now, I'm wondering it this is really a focus
problem, or if the display is "blooming" over time.

At any rate, any ideas where to start looking for the problem?

Thanks

Well,

Start to check out contrast and brightnes. Especially the brightnes often
has been set too high on CRT's. (Both on TV sets and computer monitors.) If
focus becomes suspect you'll have to check the focussing voltage along with
the brightnes - and contrast voltages. In other words: Find out what changes
on the CRT input(s) when you detect a changing in the output.

petrus bitbyter

 

[James Sweet]

I have a Samsung 955DF monitor that's ~3 yrs old, and just out of
warranty.

After performing flawlessly until now, I've noticed that it drifts out
of focus, but only when it's displaying a lots of white.

For example, when viewing Web pages with white backgrounds, or
black-on-white MS-Word or Excel document, after about 5 minutes I
notice it loosing focus. After 20 minutes it's actually painful to
look at.

The odd thing is that this only occurs when there's large quantities
of white on the screen (i.e. backgrounds). I don't notice it with
other colors.

Also, it doesn't worsen just by virtue of how long the monitor has
been on - my initial thinking was that it was heat related (and easy
to troubleshoot with a can of freeze spray). It only starts happening
when the screen contains lots of white.

Thinking about it now, I'm wondering it this is really a focus
problem, or if the display is "blooming" over time.

At any rate, any ideas where to start looking for the problem?

Thanks

My first guess would be a weak CRT, some Samsung tubes are notoriously short
lived, I've seen 1 year old monitors with bad tubes.