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Late 08 Macbook Pro screen flickering

isaki87 said:
I know that this was directed at another poster, but I was in the same boat as Andrewupstairs. I had a 2.8ghz UMBP, and apple attempted one repair (for the flicker issue on an 9c84 panel). The repair that was done, was the replacement of the LCD. The issue persisted, so they replaced my unit with another CTO unit. At that point, the 2.8 was replaced with the 2.93 (9c85 panel). I received that laptop and it has been flicker free, knock on wood.

I did not purchase applecare, and I was still under the initial one year that comes with the laptop.
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Replacing the LCD sounds kind of useless, this is probably a power management issue. I had a similar issue on my iMac 24", sometimes when I woke it from sleep the screen would flicker like a stroboscope and the only remedy was a full reboot. It disappeared after I downloaded some Leopard update and an nVidia firmware update at the same time, I don't know which update did the trick, but... I'm thinking it was the firmware update. nVidia makes good hardware but their software engineers are pretty hamfisted (driver problems with ATI cards on Vista were sorted long before Vista was released, nVidia kept having issues with some cards up to a year after the release of Vista).
 
Anuba said:
Replacing the LCD sounds kind of useless, this is probably a power management issue. I had a similar issue on my iMac 24", sometimes when I woke it from sleep the screen would flicker like a stroboscope and the only remedy was a full reboot. It disappeared after I downloaded some Leopard update and an nVidia firmware update at the same time, I don't know which update did the trick, but... I'm thinking it was the firmware update. nVidia makes good hardware but their software engineers are pretty hamfisted (driver problems with ATI cards on Vista were sorted long before Vista was released, nVidia kept having issues with some cards up to a year after the release of Vista).
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some say it's a hardware some say it's software/firmware. I'm really hoping it's software.
 
Which brightness do you guys get the flickering on?

When I am not on the power cable and on one of the lower settings my screen flickers, but what I am worried of is taking it to an Apple store and 'not being able to replicate the problem' resulting in them just sending me home.
 
delude said:
Which brightness do you guys get the flickering on?

When I am not on the power cable and on one of the lower settings my screen flickers, but what I am worried of is taking it to an Apple store and 'not being able to replicate the problem' resulting in them just sending me home.
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Could the brightness sensor be involved somehow?
Sound exactly like the thing I get on my iPhone if I set it to the lowest brightness + automatic. In manual mode there's no flicker whatsoever, in automatic mode it flickers like it's trying to make up its mind about whether there's any light in the room or not. But only if the brightness fader is all the way down.
 
delude said:
Which brightness do you guys get the flickering on?

When I am not on the power cable and on one of the lower settings my screen flickers, but what I am worried of is taking it to an Apple store and 'not being able to replicate the problem' resulting in them just sending me home.
Click to expand...

between 1-5 brightness level. Halfway and above is not usually noticed, although it may be there, just my eyes can't detect it at that level. It's like a strobing/pulsing, quick dimming in and out.
 
Ah right. My flickering doesn't have anything to do with the sensor, but only flickers when it is below half way.
I'm really not sure whether to take it back now as I have had it since October and have all my apps, files etc on it now.
 
Time machine will sort it out, together with migration assistant :)
 
What would you recommend backing it up on? I have an external hard drive which is a couple of years old, would that be okay?
 
delude said:
What would you recommend backing it up on? I have an external hard drive which is a couple of years old, would that be okay?
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If it's big enough, sure. Time Machine wants a hard drive that's at least the size of your internal drive. I tried plugging a 250 GB drive into my iMac with a 500 GB internal drive, and Time Machine said no way José. You'd think they would use some file compression algorithm for backups, and maybe they do, but then a 250 GB drive should be able to take the contents of a 500 GB drive out of which only some 150 GB were used, and squeeze it down to 75 GB or less.
 
So my 2.53 UMBP was originally purchased in October. I purchased it from someone on Craigslist a few weeks ago and immediately noticed the problem. I called applecare to have it sent in for repair and ended up getting it back with the note "no problem found". This was very frustrating seeing as I clearly explained how the problem could be replicated. My flickering typically occures during large read or writes to the hard drive, time machine backups, etc. Apparently they have little patience. Once I got it back I took it too the genius bar and was easily able to get the flicker. To my surprise they ended up replacing it with a brand new 2.66 ghz model. I would advise taking the computer into the store rather than just having it mailed. It might not get replaced but at lease there is a record of an apple tech noticing the problem prior to it being sent out.
 
I'm also experiencing the same problem most of you are and am certain that the screen flicker problem can either be quite subjective or also out of norm. Now I noticed two different range of screen flicker fluctuation when the backlight is on. For me, I can see the screen flicker at the lowest brightness setting while sitting in a darkened room. But only just. And then there are moments when it seems to be pretty bad.

I did a bit of research and discovered that this has to do with the LED backlight. Basically, with the old fluorescent backlight, brightness is controlled by the amount of voltage sent to it. The lower the voltage the dimmer the backlight. LEDs, however, work differently. They work only at a specified voltage. Anything less than that and the LED goes off. So to get LEDs to simulate brightness settings at lower levels, developers use something called Pulse Width Modulation (PWM), which is just on-off cycles that repeat at different rates to simulate different levels of brightness. Each person perceive these cycles differently, which is why some people may notice their MacBook Pro screens to flicker, while others don't. There's a pretty good description of this here: http://http://news.cnet.com/8301-13554_3-9748301-33.html

So it does appear that moderate amounts of flickering is to be expected at low brightness settings, until at least the LED backlighting technology for LCD displays improve in the future. However, I still do get the sporadic occasions when my backlight flickering gets unusually severe, and this I feel is out of the operating range and does suggest that something isn't right.
 
lyew said:
I'm also experiencing the same problem most of you are and am certain that the screen flicker problem can either be quite subjective or also out of norm. Now I noticed two different range of screen flicker fluctuation when the backlight is on. For me, I can see the screen flicker at the lowest brightness setting while sitting in a darkened room. But only just. And then there are moments when it seems to be pretty bad.

I did a bit of research and discovered that this has to do with the LED backlight. Basically, with the old fluorescent backlight, brightness is controlled by the amount of voltage sent to it. The lower the voltage the dimmer the backlight. LEDs, however, work differently. They work only at a specified voltage. Anything less than that and the LED goes off. So to get LEDs to simulate brightness settings at lower levels, developers use something called Pulse Width Modulation (PWM), which is just on-off cycles that repeat at different rates to simulate different levels of brightness. Each person perceive these cycles differently, which is why some people may notice their MacBook Pro screens to flicker, while others don't. There's a pretty good description of this here: http://http://news.cnet.com/8301-13554_3-9748301-33.html

So it does appear that moderate amounts of flickering is to be expected at low brightness settings, until at least the LED backlighting technology for LCD displays improve in the future. However, I still do get the sporadic occasions when my backlight flickering gets unusually severe, and this I feel is out of the operating range and does suggest that something isn't right.
Click to expand...

Wow, thanks for that!
 
lyew said:
I'm also experiencing the same problem most of you are and am certain that the screen flicker problem can either be quite subjective or also out of norm. Now I noticed two different range of screen flicker fluctuation when the backlight is on. For me, I can see the screen flicker at the lowest brightness setting while sitting in a darkened room. But only just. And then there are moments when it seems to be pretty bad.

I did a bit of research and discovered that this has to do with the LED backlight. Basically, with the old fluorescent backlight, brightness is controlled by the amount of voltage sent to it. The lower the voltage the dimmer the backlight. LEDs, however, work differently. They work only at a specified voltage. Anything less than that and the LED goes off. So to get LEDs to simulate brightness settings at lower levels, developers use something called Pulse Width Modulation (PWM), which is just on-off cycles that repeat at different rates to simulate different levels of brightness. Each person perceive these cycles differently, which is why some people may notice their MacBook Pro screens to flicker, while others don't. There's a pretty good description of this here: http://http://news.cnet.com/8301-13554_3-9748301-33.html

So it does appear that moderate amounts of flickering is to be expected at low brightness settings, until at least the LED backlighting technology for LCD displays improve in the future. However, I still do get the sporadic occasions when my backlight flickering gets unusually severe, and this I feel is out of the operating range and does suggest that something isn't right.
Click to expand...

this just sounds right.
 
lyew said:
I'm also experiencing the same problem most of you are and am certain that the screen flicker problem can either be quite subjective or also out of norm. Now I noticed two different range of screen flicker fluctuation when the backlight is on. For me, I can see the screen flicker at the lowest brightness setting while sitting in a darkened room. But only just. And then there are moments when it seems to be pretty bad.

I did a bit of research and discovered that this has to do with the LED backlight. Basically, with the old fluorescent backlight, brightness is controlled by the amount of voltage sent to it. The lower the voltage the dimmer the backlight. LEDs, however, work differently. They work only at a specified voltage. Anything less than that and the LED goes off. So to get LEDs to simulate brightness settings at lower levels, developers use something called Pulse Width Modulation (PWM), which is just on-off cycles that repeat at different rates to simulate different levels of brightness. Each person perceive these cycles differently, which is why some people may notice their MacBook Pro screens to flicker, while others don't. There's a pretty good description of this here: http://http://news.cnet.com/8301-13554_3-9748301-33.html

So it does appear that moderate amounts of flickering is to be expected at low brightness settings, until at least the LED backlighting technology for LCD displays improve in the future. However, I still do get the sporadic occasions when my backlight flickering gets unusually severe, and this I feel is out of the operating range and does suggest that something isn't right.
Click to expand...


I think this is exactly right. Like I said earlier, I think almost every Macbook Pro suffers from flickering, and the lucky one's just don't notice. Apple was nice enough to send me a Mini Displayport - DVI adapter so I just hook mine up to an external most of the time when I'm not at school. Haven't had any other problems and I love the computer still.
 
genmic said:
I think this is exactly right. Like I said earlier, I think almost every Macbook Pro suffers from flickering, and the lucky one's just don't notice. Apple was nice enough to send me a Mini Displayport - DVI adapter so I just hook mine up to an external most of the time when I'm not at school. Haven't had any other problems and I love the computer still.
Click to expand...

I'm shocked that the newer batches of the 15" mbp unibody still has the flickering issues.

I was one of the first ones to get the 15" 2.53GHz model and on 1-3 brightness levels it would flicker/pulsate.

God I want a 17" unibody right now but all these issues are making me less interested.
 
Count me in on flickering

Count me in on flickering, too. MBP 15" 2.66. Two weeks old today.

Auto-adjust brightness is off.

I've just finished setting this thing up, and now I have to switch. Major bummer.
 
lyew said:
I'm also experiencing the same problem most of you are and am certain that the screen flicker problem can either be quite subjective or also out of norm. Now I noticed two different range of screen flicker fluctuation when the backlight is on. For me, I can see the screen flicker at the lowest brightness setting while sitting in a darkened room. But only just. And then there are moments when it seems to be pretty bad.

I did a bit of research and discovered that this has to do with the LED backlight. Basically, with the old fluorescent backlight, brightness is controlled by the amount of voltage sent to it. The lower the voltage the dimmer the backlight. LEDs, however, work differently. They work only at a specified voltage. Anything less than that and the LED goes off. So to get LEDs to simulate brightness settings at lower levels, developers use something called Pulse Width Modulation (PWM), which is just on-off cycles that repeat at different rates to simulate different levels of brightness. Each person perceive these cycles differently, which is why some people may notice their MacBook Pro screens to flicker, while others don't. There's a pretty good description of this here: http://http://news.cnet.com/8301-13554_3-9748301-33.html

So it does appear that moderate amounts of flickering is to be expected at low brightness settings, until at least the LED backlighting technology for LCD displays improve in the future. However, I still do get the sporadic occasions when my backlight flickering gets unusually severe, and this I feel is out of the operating range and does suggest that something isn't right.
Click to expand...

This explains the flickering in general but how would you explain the previous generation with led backlighting (pre unibody models) didnt have the lower brightness flickering issue.

Could it just be a flaw with the newer logic boards?
 
kimhill said:
I've just finished setting this thing up, and now I have to switch. Major bummer.
Click to expand...

The issue seems to be common enough that exchanging yours for another unit isn't likely to bring you any relief. I personally went through five MBPs earlier this year, four of which had the flickering issue. (The other one had other, more serious issues.) Of course, my luck with the MacBook Pro line has always been a statistical curiosity. Just bear in mind that a new unit may or may not fix it for you.
 
Recieved my base model MBP yesterday, ordered through the employee store by a friend. Noticed the flicker right away, switched to the 9600, no flicker. Switched back, flicker. Brought it to my local Apple store, the Genius obviously didn't want to acknowledge the problem (even though the MBPs in the store didn't have the problem when I looked at them...), but agreed to swap it. Then he realized that because I'd ordered a mini-DVI adapter, it had made my online order CTO and told me I'd have to send it back. I didn't give him a hard time because obviously he couldn't do anything, but that's %^&* crazy that adding an adapter makes the order CTO. After a lot of time on the phone with Apple, I was able to send the MBP back yesterday with FedEx and have a new one shipped out at the same time. The guy on the phone also changed the order so that it wouldn't be CTO this time, in case I had to take it back to the store again. It's really troubling that I could have to go through several of these. Knock on wood. I should point out I had the 9C85 display, not the 84
 
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