Macbook Pro screen flicker at max. brightness

[ashkey]

Hi everyone... I'm experiencing an undocumented defect on my MBP: the screen does start flickering every 3 - 4 hours of continuous use while at massimum brightness.
the flicker is very light but, like a very fast rightnes variation between max. and a tick less, and very frustrating.

I'm going to bring my notebook to an apple support center one of the next weeks (hoping the screen doesn't collapse, every week the flicker seems to appear more frequently).

If anyone knows of this defect please let me know his experience and eventually what does cause the problem.

Thanks,
Ashkey

[Lousy_Apple]

It's not a defect -- it's caused by the ambient light sensor, which adjusts the screen brightness based on how much ambient light is available. If you have a high-contrast environment, moving your hands over the sensor so they cast a shadow can result in the screen going brighter, and then going slightly dimmer again when the shadow moves off the sensor. It's just most noticeable when the screen brightness is maximised.

[ashkey]

I think this isn't the cause, since the flickering only happens at max brightnes, and not even if i lower it of a single step (i think i would notice it anyway at nearly max brightness); but, most important, the "flicker" is at a very high frequency, and I'm not waving very fast my hand over the sensor

It's a strange behaviour, and can happen on late evening on a dark room like in a very light ambient during daylight. It just start flicker at very high frequency like if it's changing brightness but is "stuck" between max brightness and lower than a step.

to confirm it's not what you pointed out, if i turn on or off all the lights it won't stop flickering....

Ashkey

[mobocracy]

My white Macbook display flickers occasionally as well, and my display is not on the brightest setting and I'm almost always using in a room with a very stable lighting situation.

I first noticed flickering when booted into Windows XP, which led me to believe it might be some kind of XP driver issue. But then I noticed it in the OS X MS Remote Desktop App, and at first I attributed that to using it in full screen mode and MSRDP not being Intel-native.

But now I notice it from time to time in OS X using native Apps. I did wonder if there was an ambient lighting sensor, and if there is perhaps either it is malfunctioning or something in the backlight is malfunctioning.

It's irritating but its intermittant -- it only happens for a brief period of time and then stops for a long time -- the computer isnt unusable and I can live with it. My worry, though, is that its a symptom of something failing or of something having a reduced lifespan.

[spydermac]

Hello all!

Just wanted to put my hat in the flickering display ring too. I wonder if all of us with this issue are using the glossy screens (since the MBP can be had with a choice of matte or glossy)?

As for the potential ALS (ambient light sensor) explanation, if this problem is the same on MBs and MBPs, that cannot be the answer... the MacBook does not have an ambient light sensor for automatically adjusting the display.

Furthermore, if you're on an MBP and you have the ALS turned on (in system prefs, in the 'Displays' settings), when you press the function keys to adjust screen brightness, nothing changes... the usual icon will flash on the screen, but greyed out with a slash through it, since the brightness is being automatically handled by the ALS.

Cheers,
Jon - ACDT, ACPT, ACHS, GEEK, ACTC

[ashkey]

I'm trying to figure if it's due to the ambient light sensor... Maybe when it detects low light and tries to reduce the brightness it gets "stck" between two steps switching quickly between the two.
It's hard but possible.

I disabled the ALS, if it happens again before i reactivate it we can exclude this possibility, leaving it to an lcd hardware issue.