computer display brightness

[dean]

Apologies in advance if I have found the wrong group to ask this question.
Having trouble with my display. Monitor is 3 years old, gives absolutely no
probs, but is quite dark. I have turned up brightness to full with a button
on the front of the monitor.
Want to brighten up the screen as pictures are a bit too dark. Just
installed
XP. With Windows 98 I had a similar problem but always found a way to
adjust gamma or smething, somewhere in Control panel, with a slider. Cant
find it now. I cant find any
drivers or anything like that for the monitor, and it says it is working
properly. I dont even know if the problem is with the monitor, or something
else in the compter causing everything to be too dark. Any ideas or advice
appreciated, thank you.
Dean

 

[Jerry G.]

This usually happens when something in the monitor is failing. It is very
common as the tube gets weaker, this can happen as well.

The tech would verify the bias voltages, and screen voltage to the tube to
make sure that they are correct, so that the tube can have the proper
emission. I would first recommend that you bring the monitor to a service
shop and have it at least looked at to see what the fault really is.

Since this is an older monitor and if you want to cheat it a bit, you can
open the monitor. On the flyback there may be a pot marked "screen" or "G2
Bias". Turn on the monitor, and observe a grey scale or something that will
give you a reference. After locating the pot, and give it a bit of a
nudge. You should be able to increase the brightness. After doing this
adjustment, check the monitor for minimum brightness in a darkened room. If
you see some retrace lines in the picture, back this adjustment up a little
to get rid of them.

Take note that increasing the screen bias will most likely accelerate the
wear factor of the tube. This is forcing the tube to have a higher screen
current.

The proper fix is to have the monitor properly serviced. It may be worth
more for you to simply replace it, considering the low cost of monitors
these days.

When opening your monitor take care for high voltages. The voltages used in
your monitor can be lethal, and lead to serious injury.

It is recommended that for doing any adjustments you use a plastic shaft
screwdriver. Using a metal shaft screw driver is very risky, in case it
comes in contact with something it should not. For all the internal
alignment pots we use the proper plastic shaft tools.



--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
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Electronics http://www.zoom-one.com/electron.htm
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Apologies in advance if I have found the wrong group to ask this question.
Having trouble with my display. Monitor is 3 years old, gives absolutely no
probs, but is quite dark. I have turned up brightness to full with a button
on the front of the monitor.
Want to brighten up the screen as pictures are a bit too dark. Just
installed
XP. With Windows 98 I had a similar problem but always found a way to
adjust gamma or smething, somewhere in Control panel, with a slider. Cant
find it now. I cant find any
drivers or anything like that for the monitor, and it says it is working
properly. I dont even know if the problem is with the monitor, or something
else in the compter causing everything to be too dark. Any ideas or advice
appreciated, thank you.
Dean

 

[mike]

This usually happens when something in the monitor is failing. It is very
common as the tube gets weaker, this can happen as well.

The tech would verify the bias voltages, and screen voltage to the tube to
make sure that they are correct, so that the tube can have the proper
emission. I would first recommend that you bring the monitor to a service
shop and have it at least looked at to see what the fault really is.

My experience has been as follows.
If the picture starts out dim and gets brighter as it heats up, it's
often the CRT.
If the picture gets darker as it heats up, it's often the bypass cap on
the screen voltage.
Of course, there are also a lot of other possible causes.

Since this is an older monitor and if you want to cheat it a bit, you can
open the monitor. On the flyback there may be a pot marked "screen" or "G2
Bias". Turn on the monitor, and observe a grey scale or something that will
give you a reference. After locating the pot, and give it a bit of a
nudge. You should be able to increase the brightness. After doing this
adjustment, check the monitor for minimum brightness in a darkened room. If
you see some retrace lines in the picture, back this adjustment up a little
to get rid of them.

Take note that increasing the screen bias will most likely accelerate the
wear factor of the tube. This is forcing the tube to have a higher screen
current.

While that may have the same result, it don't matter. A usable system
with a slightly diminished life is a LOT more useful than one you can't
see.

The proper fix is to have the monitor properly serviced. It may be worth
more for you to simply replace it, considering the low cost of monitors
these days.

When opening your monitor take care for high voltages. The voltages used in
your monitor can be lethal, and lead to serious injury.

It is recommended that for doing any adjustments you use a plastic shaft
screwdriver. Using a metal shaft screw driver is very risky, in case it
comes in contact with something it should not. For all the internal
alignment pots we use the proper plastic shaft tools.

The above is good advice...but...the screen pot on the flyback is
usually glued in place. This is difficult to break with a plastic
driver. Unplug the unit, discharge the high voltage. Use a big
metal screwdriver with a tip that fits nicely in the slot.
Carefully twist the pot back and forth to break loose the glue.
Turn it back on and use the plastic tool to adjust it.

Also, many monitors have an internal adjustment that sets the range
of the user adjustments for contrast and brightness.

mike
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Return address is VALID.
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http://www.geocities.com/SiliconValley/Monitor/4710/

 

[dean]

Thanx to both of you who replied. I will get to work at the weekend
hopefully. I really appreciate your time and effort. thanx
Dean