Martin writes:
I have a 15-inch LCD monitor. After being powered on for 10-30 minutes the screen goes blank, but power is still on. By pressing the power button again, the screen will display normally, but after that the screen goes blank and not display anything even though the monitor LED is still lit green. What’s wrong with my monitor?
I openly invite anyone that repairs LCD monitors to chime in with a comment or two for troubleshooting this issue, but here are my takes on it:
If I had an LCD monitor where the display periodically blanked out but the power LED is still lit solid green (or amber or blue depending on model for whatever is considered "successful ON; video signal acquired" state), I’d take a flashlight and shine it directly into the display to see if anything is there. If I can see the OS in operation from wherever I’m shining the light, at that point I know it’s a backlight issue – maybe.
I say "maybe" because the backlight might still be good, but a capacitor inside the monitor may be slightly bad. After the monitor heats up, a slightly bad capacitor will fail as designed to prevent the circuit board from being overheated and cut the backlight to save itself.
It is doubtful that the power supply within the monitor (assuming it’s not an external power brick) is the thing at fault here being the monitor still shows a solid green power LED even after being blanked out.
My best guess without seeing the monitor or taking it apart for a look at the capacitors is that there’s a capacitor in there that’s about to go and needs to be replaced – although I will reiterate I’m guessing here.
If anyone who repairs monitors agrees or disagrees with this assessment, please feel free to post a comment on what you think the issue is, because I’m not an electrician.
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I’m no electrician either, but I’ve played “doctor” with my fair share of LCDs. I don’t know about any specific capacitor, but usually there’s three major components to troubleshoot.
1) The backlight itself: usually at fault if you never ever get a backlight, but the LCD display is still there (will be very dim, hence the flashlight trick). This is not a fun prospect to replace. Usually it’s built very tightly into the display itself and could cost a bit to replace if you even can without replacing the whole display.
2) The control board: problems with this can cause a range of problems from weird glitchy graphics to backlight issues. However usually being a separate board it’s fairly easy to replace, if you can find the replacement part (which can be fairly hard to do).
3) The power inverter board: I’ve found that this tends to be the most common problem, although usually it manifests in the monitor completely turning off shortly after being turned on. It’s also easy to replace (but hard to find replacement for).
Again this is all just experiential knowledge from taking stuff apart and I have no technical training with monitors. I have successfully revived 2 or 3 monitors that were thrown out by replacing boards. Usually you can find the part if you dig online enough, but usually they are sold by highly obscure overstock resale sites for between $30 to $100 USD, depending on the part, and how common/new the monitor model is.
Concerning your last side note at the end of your comment: If it were a laptop display, the ribbon connector is the first thing I’d check. Older laptops have the ribbon connector point usually inside the left side hinge (on Dells anyway); it gets stretched over time and eventually busts. Usually an easy fix and the part is readily available from Dell directly even for old stock. Takes about 10 minutes if you know how to unmount the hinge and crack open the panel, about 45 minutes if you’ve never done it before.
Good point. That reminds me, a user at work dropped their Dell mini and the right hinge (and the wires running through it) are all screwed up, rendering the display useless. It’s been sitting, forgotten in our office in this sorry state for a while. Might be worth taking a look at again with this in mind.
Tread lightly.The mini (and there’s no other way to say this) is a bitch to take apart, much less put back together. Watch this video first
http://www.youtube.com/watch?v=mXOZDNVRkZo (part 2 and 3 should be in the sidebar right next to it on page load).
Well… that looks like fun.
By which I mean the opposite of fun.
About as fun as getting a root canal.
If you have steady hands, plenty of light and the right tools, it’s doable, but not easy.
Heh. That guy in the video made it look easy, clearly had some practice. I know for a fact not to assume a laptop disassembly will ever go that smoothly D:
Off topic on an already off topic comment thread: we’re getting awfully close to to the right-hand margin of the site lol ———–>
I’m always a fan of indentation to symbolize comment order… but have always wondered how various implementations handle this sort of thing XD
This may be too obvious, but what I think the problem might be is the connection cable. Whether vga/hdmi/or dvi, a loosely connected or faulty cable could be the culprit.
I had the same problem and I could swear someone was sabotaging my computer, but know, I did some investigation and found out that I had 4 serious viruses on my computer. It took me all night to run AVG 2011, IObit Malware Fighter, McAfee Security Scan Plus and after that my Computer is running smoothly. No problems.
I would assume from the fact that it is a 15 incher, that the monitor is an older one that uses a CCFL backlight. Commonly, in these monitors, there are three major components, the power/inverter board, the mainboard, and the LCD screen itself. The culprit most likely t fail is the power/inverter board. Other posters are correct in saying that the failure is most likely a capacitor
are you sure its actually the monitor I would also investigate the graphics unit and driver or powersupply issues . If possible try the monitor on another PC and see if it works ok.
That’s why you shine a light into the display first when the screen blanks out to check for signal. If you see the OS in operation, then you know it’s not a graphics card, video cable or PSU issue.
I just had a Samsung 24 inch 1920*1200 start to blink out, known problem with capacitors. Luckily I bought it at Costco, full refund 320+tax, so I bought a 27 inch Samsung at Costco.
My wife’s 23″ Viewsonic LED monitor started doing the same thing (going blank after 30-45 minutes with the “on” light still illuminated). We disabled the screen saver and the background image (Win7) and it hasn’t blanked out since! We have not yet re-enabled either, but will start with one before enabling both.
Sorry, that is an LCD monitor!