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Official Flat Panel Repairs Thread

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a b C Monitor
October 13, 2010 8:36:58 PM

This thread has been moved from the former Official Flat Panel Reviews & Repairs Thread:



FLATSCREEN MONITOR FAILURE. SCREEN POWERS UP BUT IMAGE APPEARS FOR LESS THAN A MINUTE -- OR NOT AT ALL.


There's been a rash of flatscreen monitors failures.

Failures affect monitors of varying ages and across numerous models though, mostly, those larger than
15 inches. I suspect the problem is being caused by heat inside a small space. As I recall, some early
flatscreens had cooling fans

Obviously there's no guarantee that this is the case with every flatscreen failure but it's a common
fault and not especially hard to try to fix. However, before you embark, do test the monitor with another computer or the computer with a different screen -- just in case the problem is not with your monitor.

This video of a repair to a Viewsonic monitor (I had two from that brand fail) will show you the
basics. http://www.youtube.com/watch?v=ZccykxrtX9g

No, I couldn't understand what he was saying, either.

The Viewsonic case is easy to disassemble. But many monitors use concealed clips under the screen
surround, where two halves of the case meet. These can be hard to locate and I've found that a
small penknife slid along the join is the best tool for locating and releasing them. There will be some
scratching of the case. Usually, start by removing the pedestal stand.

Once in, identify the power supply board (usually separate from the screen electronics) and
identifiable because it doesn't carry any integrated circuit chips -- and components are not surface
mounted. In fact, the power board usually looks cruder. On most monitors, the mains cable plugs
directly into the power board.

In most (not all) instances, faulty capacitors can be identified easily because the end caps bulge
slightly -- in extreme cases the bodies bulge and there is a brown leakage.

If you can solder*, replace all the medium sized capacitors (probably about 16 to 25v) with ones of
the same value. Slightly higher voltage is not a bad thing, but stick closely to the same capacitance
value (microfarad/picofarad). If you're not sure about values take damaged capacitors or the board
with you to the electronics hobby store.

You can probably ignore the bigger capacitors (sometimes 450v) and ignore the very small ones.
Before removing any components, make a diagram or mark the board with the values and polarity of
the components you plan to remove. When replacing, be sure to double check polarity (usually
indicated on the circuit board and on the component).

Capacitors are cheap and, if you already have a soldering iron, the only additional expenditure I'd
recommend is a small solder pump which makes it easier to remove stuff without damaging the
circuit board.

Once the new components are in place, it is feasible to test the monitor without reassembling the
case (which you may have to disassemble if the problem persists). But there are high voltages kicking around in monitors and you should not touch the uncased monitor once power is connected, except to press the Power On button. If the repair is successful you will see the "no connection" warning come up on screen and it should stay on screen for the normal period. Disconnect power at the wall socket and leave the screen for a couple of minutes before reassembling it.


*If you have to take it in to a repair guy it shouldn't cost much. It takes anyone experienced
under an hour to do the job, the parts cost very little and should be in stock.

also see: http://www.ccl-la.com/blog/index.php
http://www.normsweb.com/tektips/sam206bw.shtml



Addendum: If your monitor's symptom is that the image comes on for a few seconds or not at all BUT can be seen dimly (or when illuminated by a torch) the likelihood is that the screen's illumination has failed. That could be psu failure but may instead be screen illumination component such as fluorescent or associated circuitry on the screen. This problem seems more common with laptops where the fluorescents can suffer impact and the circuitry is necessarily rather compact
a b C Monitor
October 13, 2010 8:49:47 PM

This topic has been sticky in top of the forum by Buwish
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November 9, 2010 4:31:34 AM

The first place to start your search for a culprit is under the panel. Many panels have inner structure that supports the outer skin. When the outer panel has been damaged the inner structure was bent down along with the outer. This inner structure can be in the form of just a simple inch or so wide support running across the panel to the complete support by a stamped panel that goes covers the underside of the panel.


edited to remove irrelevant commercial link

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January 8, 2011 6:19:51 AM

Just wanted to share that my viewsonic often turns off to sleep mode and only wakes up with the wrong resolution if at all when I press the power button multiple times. It only does it under windows vista/ 7. It never does that under windows XP. This is probably not the case here, but one should consider it. Do you have windows7/ vista? If so, connect it to a pc with xp just to eliminate this option.
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January 14, 2011 11:36:47 PM

Quote:
FLATSCREEN MONITOR FAILURE. SCREEN POWERS UP BUT IMAGE APPEARS FOR LESS THAN A MINUTE -- OR NOT AT ALL.


Two suggestions: an "exacto" knife with a thin blade makes a far more precise tool to find and move the legs/feet of the bezel (screen surround). It is thinner and more delicate although you have to be careful not to slice the legs off.

You might also wish to disconnect and reconnect any wiring which has connectors. Surface oxidation can often reduce the signal to whatever circuitry exists inside or power to the lighting element. If you want, you could spray connector "lube" before reconnecting.

You can check out if it is the illumination which has failed by taking a bright lamp and shining along the monitor from an edge. You can often see ghost images on the surface.

This info also applies to laptops. Had the same problem with an old Toshiba Satellite and was told the high voltage module for the lamp would need replacing. I found advice on the internet and removed the bezel and connected and reconnected the power wiring several times. It has worked since.


Quote:
Addendum: If your monitor's symptom is that the image comes on for a few seconds or not at all BUT can be seen dimly (or when illuminated by a torch) the likelihood is that the screen's illumination has failed. That could be psu failure but may instead be screen illumination component such as fluorescent or associated circuitry on the screen. This problem seems more common with laptops where the fluorescents can suffer impact and the circuitry is necessarily rather compact
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March 22, 2012 5:14:28 PM

Help me please...
My monitor is Viewsonic VX1940W. When I turn it on, it just show a "bricked" screen, then I restarting my computer... afterwards, the monitor just won't show anything, even when I press the OSD Setting button it won't show, it just grey dim light on the monitor :( 
Plz help me...

Any idea is appreciated thank you!
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July 18, 2012 10:09:14 AM

This inner structure can be in the form of just a simple inch or so wide support running across the panel to the complete support by a stamped panel that goes covers the underside of the panel.
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