Why does the backlight flicker after screen repair

I am a new tech and am always very careful with the flex cables while installing. I test out the screen before every installation, and then after fully installed, they flicker! I've been getting the same problem, even after we started buying from only our "good" suppliers, with 50% or more of our screens. It has made me very self conscious, thinking I'm damaging them somehow. Glad to know this is likely not the case!

Someone sent me a PM that said you must manually power down the device before unplugging the battery. I have not had any problems with them since! Before, when I would test a new screen, I'd just unplug the battery to complete the installation. Now, I make sure the power flex is plugged into the logic board so I can manually power the screen down before completing the repair. Even our crappy supplier's screens aren't flickering with this method now. Hope this helps!

As long as the device is powered down OR you have dimmed/locked/turned off the screen, the backlight issue does not present itself. I have not had a problem with them since I learned this a few months ago.

Even so, the flickering goes away after a bit.

I have come across this problem several times and I have found the reason why. It usually happens when you disconnect the screen or the battery without shutting the phone down properly.

Once the screen flickers, just turn the brightness down until the flickering stops. After some time passes, slowly increase brightness so that the flickering is not noticeable, after some time you can increase the brightness to full and the screen will be fine.

I tested this out on several screens and it does occur when disconnecting the lcd or battery while powered on.

I know this thread is kind of old, but I deal directly with a supplier in the states and I've asked him what the problem was with his screens recently. He supplies great screens and I've rarely had any issues, but as of late I get about 50% with the flickering back light. This issue doesnt start until about 20 min after install. He told me the issue was that the glass on top of the digitizer is either too thick or too thin. Its an issue with the manufacturing process. Basically, whether its too thick or too thin causes undue pressure on the back light. Too much glue or thick glass, if that makes sense.

Hope this helps.

hello there.

I agree with iwillfix.

I found that original lcd (the one with the black stripes left and right only have this problem extremely seldom.. but the copy/half original LCD on the cheaper displays have this problem much more often.

a burn-in of about 15 minutes to several hours will fix this problem most of the time.

Since we offer to repair the displays within 30 minutes for our customers.. i tend to buy the original lcd displays... but i tested a new supplier who said it is original but it is not.. ugh... so i have to write a formal paper now to inform my customers about this burn in procedure...

It happened to me after I replaced a screen. I totally agree with iwillfix.

A lot of people say you must turn brightness/auto-bright off/on, wait a little, sing a song, yadda yadda, but if you just wait you're good to go.

This problem occurred for me after I replaced the front facing camera on my 5S on 8/10/2014. The light on the edges of the screen would flicker on the lock screen and when the virtual keyboard was up.

Turning my phone off and leaving it off for a few minutes didn't work.

I went back in and reopened my case and removed the battery connector and reattached it. This seemed to do the trick.

I think it may have something to do with not properly powering down the display if you remove the front portion of your phone (since you yank out the connectors for the face of the phone). I would recommend disconnecting the battery connector before pulling the front face fully off your phone. This is just also good tech advice in general.

Hei i have the same problem with my new replacement screen, but it start after i restore iPhone with itunes, before that it wors good. Now i seen that if i put on screen totaly black photo, it stops!

I just replaced the volume control cable and charging dock as well. Put the phone back together, (twice now, since I went back in to check all the connections,) and the screen flickers at over 30% brightness. Will try to leave the screen lit for 5-6 hours to see if it helps.

I have been getting this problem with my supply of screens. They used to be great quality, no touch or LCD issues ever. Now every other screens flickers and about half of those customers have to come back after a few days and get a new screen put on. This has been happening with iPhone 5 screens now too. It's a waste of my time and damaging my businesses reputation.

I replaced my screen today and about an hour of it working properly it started to flicker lightly. I turned it off for about 2 hours and it stopped. later this night it started doing it again so i'm turning it off for the night (6 hours) and ill comment tomorrow if it works.

I don't think it's necessarily the parts. I just opened my 4s to pop the Sim out because it was stuck so no replacing the screen. Did however took mother board out put it back together and flickers.might have something to do with static?

I just had this issue of flickering screen tonight. On a normal 30 minutes repair it took me 3 hours, and same problem, flickering. I was turn off device before I start, static protection etc.. Tested 4 screens, some flickers immediately some after a while. This is so frustrating, damaging my reputation and killing my time.

I've looked at all your comments and some I still haven't test yet, bbl with results.

I have the same issue. I replaced the screen yesterday and opened the iphone 4 again today, because I installed the wrong home button (im new into business...). well, yesterday everything was fine and when I put the phone back together the screen started to flicker. I have one spare screen with a damaged digitizer cable and with this one, there is no flickering. does anyone know why? is my new screen broken?

Mine was fine when I swapped the screen (iPhone 5s) - I was actually excited as nothing ever seems to go right for me the first time, especially with electronics... of course, 4 hours later it froze again so I did a hard reset. When it came back on, it was flickering pretty bad. I figured I may not have put the connector on properly, but after reading the site I just hard reset again (same result) and then just left it. Eventually the flickering wore off, visibly until it was gone completely.

I have this problem all the time. Its from unplugging the power button before shutting it down.

SOLUTION: Plug the phone in and turn down the backlight as far as possible and let it sit for about an hour

I noticed the flickering a while back when I replaced my screen but was able to fix it with the methods above and now it's been 2 weeks and my screen seems to be dim on the right side while the left is normal. I was wondering if this has anything at all to do with the flickering. Please help!

I asked my friend after I detected this same issue with an iPhone SE.

He is an *original* LCD refurbisher from Hungary, and he said, yes this happens when you disconnect the screen from the phone. It will appear because the screen need to be “charged up”!

So don’t worry about the flickering backlight

my case caused by gsm 900 interference, it flicker when call or sms on gsm/edge, or data. Fixit with lock the network on 4G/UMTS only lol