computer screen flickering
December 7, 2015 4:59 AM Subscribe
My laptop screen has started flickering every time I start up my computer. The most obvious flickering stops after 30 seconds or so, but I’ve noticed that my eyes get really tired really quickly after working on the computer now and sometimes I feel woozy. Is it possible that my screen is flickering fast enough that it is bothering my eyes?
I know I probably need to get my computer looked at by a professional, but I get a little intimidated by people in computer stores, so I wanted to ask here first to check if my theory is even possible.
I started noticing 3 weeks ago that my eyes are getting tired a lot faster when I work on the computer, which is a problem because most of my work is on the computer. Last week I noticed that the screen flickers noticeably when I reboot, and even though the screen stops noticeably flickering after about 30 seconds, I get a sort of woozy feeling for another half an hour after rebooting and looking at the screen. After that the woozy feeling mostly goes away, but my eyes seem to get tired faster than normal and I get headaches more frequently. If I step away from the computer and read a book or do other things, the headache and woozy feeling go away, so I don't think this is a health problem.
I don’t know a whole lot about computers, so I’m wondering: does the screen refresh regularly or something? Could that mechanism be screwed up? It's a relatively new computer but my boyfriend's coffee pot exploded next to it about 8 months ago, and it's been a bit wonky every since. Are there tests IT people could do to figure out what is going wrong? And is it possible to fix a laptop screen without replacing the whole computer?
Also, I have a Macbook Air, OS version 10.11.1. If you have suggestions for things I could try at home to solve this problem, I'm happy to hear those too.
I know I probably need to get my computer looked at by a professional, but I get a little intimidated by people in computer stores, so I wanted to ask here first to check if my theory is even possible.
I started noticing 3 weeks ago that my eyes are getting tired a lot faster when I work on the computer, which is a problem because most of my work is on the computer. Last week I noticed that the screen flickers noticeably when I reboot, and even though the screen stops noticeably flickering after about 30 seconds, I get a sort of woozy feeling for another half an hour after rebooting and looking at the screen. After that the woozy feeling mostly goes away, but my eyes seem to get tired faster than normal and I get headaches more frequently. If I step away from the computer and read a book or do other things, the headache and woozy feeling go away, so I don't think this is a health problem.
I don’t know a whole lot about computers, so I’m wondering: does the screen refresh regularly or something? Could that mechanism be screwed up? It's a relatively new computer but my boyfriend's coffee pot exploded next to it about 8 months ago, and it's been a bit wonky every since. Are there tests IT people could do to figure out what is going wrong? And is it possible to fix a laptop screen without replacing the whole computer?
Also, I have a Macbook Air, OS version 10.11.1. If you have suggestions for things I could try at home to solve this problem, I'm happy to hear those too.
Best answer: Depending on the screen, it may have a fluorescent backlight -- the capacitors in these can go bad, causing flicker on turning on but eventually building up enough charge to stay on solid. I have a LCD monitor that literally flickers on and off in 5-second cycles for the first twenty minutes it's on, then stays on solid. Why do I even still keep that monitor? Anyhow, it may not be the screen refresh, but the backlight itself.
posted by AzraelBrown at 7:30 AM on December 7, 2015 [1 favorite]
posted by AzraelBrown at 7:30 AM on December 7, 2015 [1 favorite]
Best answer: I am an experienced technician who has been repairing laptops for many years.
This sounds like a bad backlight driver assembly. I see it less frequently(and more often on cheap machines) but the backlight power/driver/inverter board can still screw up and cause stuff like this even though that was more of an issue with CCFL backlit displays.
Basically the backlight is never "on" like a light bulb, even at maximum brightness. It's always flickering at a variable rate. The rate varies from person to person, but below a threshhold(which is generally well above what you can perceive as flickering) it will cause eye strain/fatigue/headaches. This has been true since the CRT days.
It's a relatively new computer but my boyfriend's coffee pot exploded next to it about 8 months ago, and it's been a bit wonky every since.
...Which leads up to my next point. Every issue i've seen with this was related to some kind of liquid/moisture/steam damage.
The apple store will diagnose this for free. I will warn this is likely an EXPENSIVE repair though, and would involve replacing at least the entire display half of the machine, and possibly even the logic board. Macbook airs are VERY integrated.
If this was my machine i would sell it as-is on ebay and buy another used one. You'd likely lose a lot less money on that than paying the expensive repair(unless you have applecare) since even damaged apple machines still hold a lot of value.
posted by emptythought at 4:26 PM on December 7, 2015
This sounds like a bad backlight driver assembly. I see it less frequently(and more often on cheap machines) but the backlight power/driver/inverter board can still screw up and cause stuff like this even though that was more of an issue with CCFL backlit displays.
Basically the backlight is never "on" like a light bulb, even at maximum brightness. It's always flickering at a variable rate. The rate varies from person to person, but below a threshhold(which is generally well above what you can perceive as flickering) it will cause eye strain/fatigue/headaches. This has been true since the CRT days.
It's a relatively new computer but my boyfriend's coffee pot exploded next to it about 8 months ago, and it's been a bit wonky every since.
...Which leads up to my next point. Every issue i've seen with this was related to some kind of liquid/moisture/steam damage.
The apple store will diagnose this for free. I will warn this is likely an EXPENSIVE repair though, and would involve replacing at least the entire display half of the machine, and possibly even the logic board. Macbook airs are VERY integrated.
If this was my machine i would sell it as-is on ebay and buy another used one. You'd likely lose a lot less money on that than paying the expensive repair(unless you have applecare) since even damaged apple machines still hold a lot of value.
posted by emptythought at 4:26 PM on December 7, 2015
Response by poster: Thank you very much for your help and in-depth answers!
posted by colfax at 12:34 AM on December 8, 2015
posted by colfax at 12:34 AM on December 8, 2015
This thread is closed to new comments.
In the cathode ray tube days of monitors, it was drawn line by line, but it's effectively screen by screen in the LCD flat panel era. There, refresh rate was important, if it dropped below about 25Hz, you might see the flicker clearly, at 20Hz, you definitely would notice it. Interlaced modes (where you draw the odd lines in one pass and the even in the next) were even worse for flicker.
But LCDs respond differently. There, the question is how fast can you change a pixel? In modern screens, that's very fast, but they don't flicker unless you explicitly make them.
Now, the question becomes the backlight. In most modern screens, the backlights are LEDs. You can't simply dim an LED, you have to put a certain voltage through it (and carefully control the current!) and it lights up.
However, being solid state means that they can be switched on and off *very* fast. So, to "dim" an LED, you only light it for a percentage of time. So, say you run a 500Hz rate, and you turn the LED on/off every cycle. That means the LED is lit for 50% of the time, and you're at 50% gray. The faster that cycle, the deeper you can dim without flicker.
What I think is happened is one of three things.
1) the LED driver or GPU is failing. It will flicker a couple of times at restart, but that's very hard to see (it's a self test mode.) For thirty seconds? That's not right, that screen should be solid within a second.
2) You're running the screen very dim and starting to notice LED flicker. Take that 500Hz rate. If you're running 1 on 20 off, (which means 5% illumination) then you'd be having an LED flash on and off 25 times a second, which is getting into the perceptible realm.
3) If you running a 2010 MBA and OS 10.8.3, you may be running into a known graphics driver bug, but it doesn't quite match the described symptoms, where the problem showed up after coming out of hibernation, not at restart. But hey, if you're running 10.8.3, get to current on 10.8.
My gut feeling is 1, but 2 is easy to test for (brighten the screen) and 3 is as well (update if you are running 10.8.3.)
Some people have run into hardware problems. In 2014, a person in England was quoted £160 for repair, which would have been about $250US, but reported that the flicker was fixed completely. I have no idea what that would cost today, you'd have to get a quote.
posted by eriko at 5:30 AM on December 7, 2015