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Repair information, troubleshooting tips, and guides for the sixth iteration of Apple iPhone, announced on September 12, 2012. Model: A1428, A1429

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Full brightness dimming problem

HI I have a iphone 5 and the glass of my screen was cracked.

I bought a new lcd with digitizer from ebay and replaced that with an old cracked one.

It works fine but the even though i changed setting to full brightness, it's not bright enough compare to my friend's iphone 5.

Auto-brightness is turned off

So I replaced it with my old one but still darker than others.

I also tried DFU but still the same.

I'm not sure why it happens.

Does the brightness is related to the mainboard?

I'm trying to purchase another lcd from ebay but I'm not sure what is the problem.

Answered! View the answer I have this problem too

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Hi do you found the solution?

I have the same problem but on iPhone 6

by

Go to settings, then general, then accessibility, then zoom and turn it off. Should fix the problem.

by

that is super RANDOM, but totally works. I just googled this problem and your suggestion is the only one that is HELPFUL and not full of crap stupid suggestions which we've all already tried.

can you answer this... how on earth did you figure this one out, and why on earth is the ZOOM feature linked to screen brightness?

and why did my phone just today exibit this behaviour when it's never done it before...

thanks for your extremely helpful solution. :)

by

omg this totally worked!!! thankyou! honestly have been googling and searching my phone for answers and like the poster above me, am totally shocked that this works!!

thanks so much

by

this did not work for me loll

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14 Answers

Chosen Solution

When you replace a screen phone and the new known screen is very dim, and using any known good screen assembly with known good light sensor does not solve it, then you probably damaged something on the board related to back-light.

And it's usually any combination of the back-light filters, diode, or back-light driver.

- The damage can occur from shorting something on the board by working with battery and/or power connected, specially if using special tools.

- Can also happen due to pry damage, specially if using metal tools to unplug cables.

- Finally, can happen if the replacement screen has an uncovered back-light connection on the screen's flat cable (if you can see 1 thin cable connected to the main screen cable by 3 apparent solder points, then they are uncovered and you need to cover them before installing the new screen - or simply buy a quality screen where they are already covered). These uncovered solder points can short the back-light circuit and cause this same issue.

All the above is usually easily repairable with the right microsoldering tools.

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Most Helpful Answer

The "zoom" feature was where my problem was! Yay!!! Inside the Zoom menu I found another selection- "Zoom Filter" somehow the "Low Light" filter had been selected to "On". It is "Off" now and brightness is normal, plus my zoom still works!

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2 Comments:

Yes, it's the ANSWER. Thanks a lot.

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Yes! at last, that's the answer. Have been searching for weeks and couldn't find any reference to this. Previously (warning) I tried adjusting Zoom in 'Go to Settings > Tap General > Tap Accessibility > Choose Zoom > Turn it off' and then turned it on again. 50% of my 700+ apps had rearranged themselves to different screens. It took me 7 hours to rearrange them. So don't do it if you have lots of apps. I doubt anyone is such an idiot as me to have so many apps.

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Sounds like the ambient light sensor is not sitting correctly or is damaged. If the ambient light sensor isnt properly positioned it could be fooled into thinking that it is dark out and that there is no need for the screen brightness to be turned all the way up.

Alot of the iphone 5 assembles will not come with the mounting hardware for the camera and ambient light/Prox sensor already attached. To be sure its not the light sensor you need to make sure these pieces are already installed on your screen. If they are not and you need to know what your looking for..... These mounting pieces are 2 small separate hazy/clear plastic pieces that line up the camera with the clear opening at the top and 2, less noticeable, opaque holes about 1/4th of an inch to the right and a few millimeters down. (hold the screen up to the light while looking at it from the back side and youll see them). They can be transferred over from the old screen by gently prying them free ( Be careful! they will pop off and fly several feet if your not holding them down) and placing them back in the correct position with new adhesive. If you use super glue be especially sparing! Just a fraction of a drop is enough to hold these, any more and it may spill over onto the openings and corrupt the view of your camera or the light sensor.

Reassemble your screen once the hardware is secure, while doing this, make sure the proximity/ambient light sensor is positioned squarely inside its mount and that it does not wiggle around.

Hope this helps :)

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1 Comment:

I've turned off the auto-brightness. Therefore the sensor is not related to this problem right?

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Just turn the auto brightness off and you will have no bother with the light sensor

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4 Comments:

Auto-brightness is turned off already.

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If you have replaced other screen back and it's still not as bright you could have damaged something on the main board or have u auto brightness on?

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Sounds like you have damaged the main board

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The mainboard is related to the backlight?

I thought the backlight was related only to the lcd

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Settings > General > Accessibility > Zoom > Zoom Filter set to "none"

Worked for me. iPhone 5S, iOS9.3

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I had this problem with my IPhone 7+ and was so annoyed because My screen brightness was so low compared to others. So I started to compare my sisters IPhone settings with mine. I then went to General , Accesibility , & Display Accomodations. Then I switched off “Reduce White Point” and my phone got brighter! Hope this helps !!

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Dude you are a Godsend!!! This was my issue too!! Thanks for this!

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Go to Settings -> Accessibility -> Display Accomodations -> Turn OFF Reduce White Point, or lower it. It helped mine and my moms phone be a lot brighter. Hope this helps.

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Hi, Thanks a lot.

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You probably have a low quality screen assembly, try one from iFixit or another reputable supplier.

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My iphone on but doesnt have brightness at all ....i had to torch to see the apps...can you help me

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Dear Aiman sahlan, I have the same problem with my iPhone 5s. My phone is on but i can't see anything whenever i put my phone under sunlight the icons and everything is visible, i can ever hear the sound of turning the phone on and off, but my phone fixes automatically this situation doesn't happens all the time it fixes by itself or when i restart it. I would like to know that does your phone has this problem all the time?

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Ok, done it , now it works like a treat, it was a backlight coil

Update (08/02/2015)

additionally I would like to upload video of the problem, now is fixed but not by me :(

i hope soon I be able to repair something like that on my own

https://youtu.be/Ae4WgQ1Jezo

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How much did it cost you to get it fixed?

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Go to setting than zoom turn on than off invert colors turn on night viewing than turn off grayscale turn on than off this should work mine did

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When iPhone battery dips below 50% the full brightness may be enabled but it's not as bright then when you charge it it will get brighter again- found out by pure accident reading these posts it suddenly got bright again

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If you have this problem, first try to charge your iphone to 100%. The brightnes will work fine for sure, but is going to work until 80% of your battery is left. This means that your battery isnt capable of keeping the backlight always to the max. Changing the battery will probably fix this problem. It fixed to me.

Hope this helps

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Settings>general>accessibility>Increase contrast>turn increase contrast AND darken colors ON. worked for me when all else failed

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I had the same problem. I could not reduce the screen brightness on my iphone 5. I knew it was a hardware problem because it happened after i changed my battery. i opened my phone while it was on and the brightness reduced but it would jump to full when ever i tried to close it. while it was opened i noticed the screen's brightness would jump to full whenever i press the shield on the display connectors. i loosened the screws and closed my phone which fixed the problem. I think its a grounding issue or something like that.

When i squeeze the top right corner really hard the brightness increases to full but other than that its ok.

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