Monitor dying?

Lataxe

Member
I have a NEC Multisynch LCD 3090WQXI that's 10 years old tomorrow. It's served me well and continues to do so .... except that it's recently begun to show a single pixel width vertical line in yellow, about 3/5ths of the way across the screen from the left. This yellow line does disappear after the monitor's been displaying for a while (perhaps 15 minutes) but it'll come back if I leave the computer on but the screen blank. (It's currently set to go dark after 15 minutes of no use).

Is this a sign that the monitor is on the way out? Is it possible to fix the problem in some way? I understand that it's unwise to take the back off a monitor to poke about as there are high voltage capacitors in there that may discharge enough to kill! But perhaps there's a monitor fixing service somewhere about, even here in wild West Wales.

I'm planning to have a new desktop computer around the turn of the year, when Win 7 is no longer fully supported. The current computer is 8 years old and also still good - although a recent move into video, as well as still photography, is proving rather demanding. But if the monitor's on the way out, I'll need to replace that first then save up some more for a new computer. (The old one is going to a grandson).

I'd rather keep the NEC monitor as it's still displaying well enough for Photoshop as well as less colour-critical programs, so if anyone has advice about fixing the vertical yellow line problem, or about any useful maintenance/refurbishment procedure, I'd be grateful.

Lataxe
 
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It does appear that way, albeit, quite slowly. Unlike a CRT where the display will die suddenly, an LCD will have an individual address line go on one of the display chips inside unless the florescent backlight tube dies, but that doesn't appear to be the case here. Opening up an LCD should not hurt you like a CRT because there are no high voltages since this is a digital device. The older type monitors, like TVs required high voltages, higher than even found on the mains, to power the circuits. They used a huge fly-back transformer and huge capacitors inside to increase the voltage and activate the display. I know because I used to repair CRT displays for video terminals and got zapped more than once, and once hard enough to knock me down on my backside!

The problem is with a digital device such as this there's probably no way to repair it. You could take a look and be lucky and find a cold solder joint, but knowing what I know about these things, the circuits are surface mounted on to the circuit board and require a special soldering iron to reattach the pins to the solder on the board surface. Even if you could resolder the board, you most likely can't see the pins anyway because they're about the size of ants and I'm not kidding!

If I were you, I would continue to use the display until it doesn't work anymore because there's no reason to ditch it because of a single address line failing. There's a good possibility that the rest of the display will continue to operate for another 5 or 10 years before it finally fails, but who knows, so get as much out of it as you can. I would replace it when it becomes too dim to see overall as the back light dies, because by then the device is worn out.
 
I had exactly the same vertical line appear on my 2014 iMac 5K Retina display (curiously enough following a shop repair for a different issue). The small comfort I can offer is that the display is still operating some 2 years or so later, albeit with a permanent vertical line.

John
 
Thanks for that advice. which is just what I wanted to hear since it concludes with, "Don't buy a new one until the old one actually fails". And if such a vertical line is not the harbinger of an imminent screen-doom, all well and good.

I've turned off the monitor go-to-sleep-after-15-minutes switch in Win 7 power management controls so I need only suffer the vertical yellow line for the first 15 minutes after switch-on in the morning, as it goes when the monitor is fully warmed up. The UPS tells me that the monitor typically uses about 100 watts, which'll be about 1 Kwh per day. I regard this as an alternative heating source to the ground source heating, which will perhaps work a bit less as the monitor heat is retained in the highly insulated building. Well, that's my theory. :)

This NEC Multisync is a fine thing, so it is. I notice that Thomas's Hardware gives the current NEC 30 inch equivalent model of today a glowing report. "Built like a tank and made to last". Oh good.

Lataxe
 
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I had exactly the same vertical line appear on my 2014 iMac 5K Retina display (curiously enough following a shop repair for a different issue). The small comfort I can offer is that the display is still operating some 2 years or so later, albeit with a permanent vertical line.

John

It sounds like they broke a connection internally to the display circuit causing the permanent line to appear.

The reason for this is that the signals are NOT'ed, meaning the work the opposite with OFF being ON, and ON being OFF.

Way back in my electronics tech days, back in 1983-85, I used to repair Visual Commuter Computers (V-1083) transportable PCs. These used a 25-line LCD on a flip panel. I was responsible for bench repairing the panels that failed, and I would see similar things depending upon where the address lines were shorted, or broken on the circuit boards. I recall these panels having an array of large buffer chips or RAM chips, like a DIMM is today, and the shorts or opens would appear along the solder joints on the surface mounted chips, or sometimes within the circuit as an etch short. These failures were caused by poor quality control from the manufacturer, and were eventually dealt with by management.
 
Thanks for that advice. which is just what I wanted to hear since it concludes with, "Don't buy a new one until the old one actually fails". And if such a vertical line is not the harbinger of an imminent screen-doom, all well and good.

I've turned off the monitor go-to-sleep-after-15-minutes switch in Win 7 power management controls so I need only suffer the vertical yellow line for the first 15 minutes after switch-on in the morning, as it goes when the monitor is fully warmed up. The UPS tells me that the monitor typically uses about 100 watts, which'll be about 1 Kwh per day. I regard this as an alternative heating source to the ground source heating, which will perhaps work a bit less as the monitor heat is retained in the highly insulated building. Well, that's my theory. :)

This NEC Multisync is a fine thing, so it is. I notice that Thomas's Hardware gives the current NEC 30 inch equivalent model of today a glowing report. "Built like a tank and made to last". Oh good.

Lataxe

Yup. Save a few quid! :)

What appears to be the issue here is one of the chips has some cold sensitivity, meaning the problem goes away when it warms up. Where the fault lies who know, because we don't have a schematic or tools to repair the display. As a tech I made it a point never to attempt a repair of anything without the schematics or a scope. It was also because I didn't want to waste a lot of time looking for something that can't be found otherwise.

Your theory holds up quite well. All these monitors, computers, and other electronics throw out a lot of heat into the room and environment. My home-office is much warmer after I've been running my computer all day, and people have remarked how warm that room is when they walk in. This works out well in the winter months because I can turn down the heat since the computer is warming up the room I spend the most time in, and only put the heat up when I go to bed.
 
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