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Computer Monitor Flicker Problem

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#1 Zion45


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Posted 07 September 2009 - 12:50 PM

My ViewSonic VA1919W 19" Widescreen monitor has suddenly developed a problem after 3 years.

Now, the screen is plagued with [what best can be described as] flashing horizontal lines [hard to tell if they are heading down or up], and the lines are especially intrusive over dark parts of the screen... usually.

If I open up Google for example, I can barely see them over the white background... but having said this, on some darker backgrounds I cannot see the lines, but instead they show up over the brighter areas, causing the brighter areas to flicker.

To try and diagnose, I have first unplugged from the computer and switched the monitor on by itself. Results: lines still appear on monitor [though thicker, presumably affected by the lack of input]. This would suggest the problem lies within the monitor, not the computer or the connecting cable. I would therefore assume it to be a waste of time to start looking at my video card [driver is up to date] or any software-related possibilities.

It looks to me like interference of some sort. Yet nothing has changed in my computer hardware setup, and to the best of my knowledge there are no new electrical pulses around me that might be causing it. I have unplugged the monitor from the bank of computer plugs where it normally receives power, and moved it to a new plug socket of its own, but with same results.

Any ideas? I haven't really got a spare 100 for a relacement at the moment, and while the monitor is still usable this unwanted effect is very distracting and gives me a headache.

I know very little about electrics to be honest, but I might be able to follow up any suggestions about checking wires, connectors etc [everything seems fine on the outside]. I've tried gently tapping the monitor casing all around, but no change.


I have just discovered that by increasing the Brightness to maximum, the lines disappear. As the Brightness goes up, the lines thin out until, at maximum, they disappear.

However not only is my monitor on full Brightness far too glary, but this has not 'cured' the problem - every so often, the screen suddenly goes darker, then lighter, then stabilizes, then repeats etc.

Perhaps this info will give more insight into what the real problem is here?

Edited by Zion45, 07 September 2009 - 01:06 PM.

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#2 Platypus


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Posted 08 September 2009 - 09:42 PM

From my experience, I'd think the two most likely causes are either some bad electrolytic capacitors in its power supply or sometimes on other boards internally, or possibly a poor connection in the LVDS cable that carries the drive to the LCD panel (this uses accessible connectors in most designs, and is usually a flat loom cable). The appearance of the lines with no signal input does confirm the problem lies within the monitor rather than the computer.

If you have any technical capability, or know someone who does, faulty capacitors can often be recognised by being bulged, split or leaking, and replaced with suitable quality components (soldering required). A bad connection in an LVDS cable socket may be able to be cured by unplugging and re-plugging the connector at each end a few times to wipe the internal contacts.

If it's not either of these causes, then a repair is probably not justifiable on cost.
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