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Persistent horizontal lines appear on iMac screen

I am reaching out to share an ongoing issue I, along with several other users, have been experiencing with our iMac 24-inch models, and to seek a collective resolution.


Problem Description:

  • Persistent horizontal lines appear on the screen, which significantly hampers the usability and visual appeal of the device.
  • This problem arises without any physical damage, and despite the stationary nature of the device.


Steps Taken:

  • Connected to an external display: The external display works fine, indicating the issue is with the iMac's internal display.
  • Reinstalled the OS: The problem persisted post reinstallation.
  • Avoided operating the iMac for a week: No change in the situation.


Concerns:

  • The cost of screen replacement is high, and there's no assurance that it will resolve the issue permanently.
  • The quality concern is alarming especially for a brand that positions itself as a premium segment player.
  • The support received thus far has been unsatisfactory, with no definitive solutions provided apart from a costly screen replacement suggestion.





Please do not ask us to visit to service center and replace the screen for 650USD + , problem happens mostly after warranty.


[Edited by Moderator]

iMac (M1, 2021)

Posted on Oct 21, 2023 10:40 AM

Reply
Question marked as Top-ranking reply

Posted on May 19, 2024 8:45 PM

According to the Apple support team I contacted, it's an LCD malfunction and the only solution is to replace it.


What they didn't say was why this problem is occurring after two years of using the iMac on so many computers.


So, as Apple hasn't yet assumed that it's their fault, what I did, given the lack of concrete answers from Apple, was to take my iMac to a technician and ask him to assess the problem to see if it's a construction problem or just a random fault.


The explanation I was given was as follows:


In terms of circuitry, everything seems to be working properly.


The problem, apparently, lies in a cable that also powers the LCD, which is located on one of the tops of the screen, and which, in order to be replaced, requires detaching the screen glass from the LCD itself, which is a very sensitive operation and almost impossible to carry out without damaging the LCD.


So the only option is to replace the entire LCD (LCD+main boards+screen glass).


Also, according to the technician's explanation, this cable (of the FFC/FPC type or Flat Flexible Cable / Flexible Printed Circuit), it has to sustain a very high voltage (around 50V) to power the LCD (this despite the iMac's power supply being 15.9V), and it heats up a lot!


So, what happens after a while (in this case after about 2 years) is that it starts to burn out and degrade at the connector, to the point where it lets the signals leak between the various connectors and short-circuits some of them, which ends up causing those lines that we are all unfortunately familiar with.


The level of brightness makes a fundamental contribution to this problem. Thus, the higher the brightness used, the sooner the problem occurs.


This is easily understood by measuring the difference in temperature at the top of the screen when it is at its lowest brightness level, compared to when it is at its highest. It's quite a big difference!


When it's at its lowest brightness, it's practically room temperature; when it's at its highest, you can almost "fry an egg"!


I think that as soon as Apple recognizes that there is a problem with these computers, the first thing it will do is make a change to the OS that reduces the maximum brightness limit allowed (to less than 500 nits). Time will tell...


Why does this happen?

For at least one of three reasons:

1- a design flaw - so this problem is likely to occur in a large number of devices;

2- a defect in components - the problem is limited to a few cases;

3- use of components below Apple's standards - the problem may be limited, or more widespread.


This was the explanation I was given. I'm not a technician. Only Apple will know the exact reason(s).


If I had to guess, I'd say that I don't believe it's a design fault, because Apple has an obligation to be very careful about that; I also don't think it's a fault with the component(s) because it seems to be happening all over the planet and doesn't seem to be localized; so I think it's due to the use of component(s) below, or at the limit of, Apple's standards which, when put under extreme stress (higher brightness), end up failing.


I think it's already clear to everyone that this is a design or manufacturing defect in this Apple model.


So let's hope that Apple takes on this construction problem and repairs it or at least contributes part of the cost of the (overly expensive) repair of our computers.


If it were a car, surely all our computers would be called into the workshop to replace the component that has broken down or is in the process of breaking down.


As it's a computer... let's hope that Apple will behave in a way that suits its customers, who believe in the above-average Apple standard...


So keep presenting your cases to Apple.

Similar questions

263 replies
Question marked as Top-ranking reply

May 19, 2024 8:45 PM in response to latVm

According to the Apple support team I contacted, it's an LCD malfunction and the only solution is to replace it.


What they didn't say was why this problem is occurring after two years of using the iMac on so many computers.


So, as Apple hasn't yet assumed that it's their fault, what I did, given the lack of concrete answers from Apple, was to take my iMac to a technician and ask him to assess the problem to see if it's a construction problem or just a random fault.


The explanation I was given was as follows:


In terms of circuitry, everything seems to be working properly.


The problem, apparently, lies in a cable that also powers the LCD, which is located on one of the tops of the screen, and which, in order to be replaced, requires detaching the screen glass from the LCD itself, which is a very sensitive operation and almost impossible to carry out without damaging the LCD.


So the only option is to replace the entire LCD (LCD+main boards+screen glass).


Also, according to the technician's explanation, this cable (of the FFC/FPC type or Flat Flexible Cable / Flexible Printed Circuit), it has to sustain a very high voltage (around 50V) to power the LCD (this despite the iMac's power supply being 15.9V), and it heats up a lot!


So, what happens after a while (in this case after about 2 years) is that it starts to burn out and degrade at the connector, to the point where it lets the signals leak between the various connectors and short-circuits some of them, which ends up causing those lines that we are all unfortunately familiar with.


The level of brightness makes a fundamental contribution to this problem. Thus, the higher the brightness used, the sooner the problem occurs.


This is easily understood by measuring the difference in temperature at the top of the screen when it is at its lowest brightness level, compared to when it is at its highest. It's quite a big difference!


When it's at its lowest brightness, it's practically room temperature; when it's at its highest, you can almost "fry an egg"!


I think that as soon as Apple recognizes that there is a problem with these computers, the first thing it will do is make a change to the OS that reduces the maximum brightness limit allowed (to less than 500 nits). Time will tell...


Why does this happen?

For at least one of three reasons:

1- a design flaw - so this problem is likely to occur in a large number of devices;

2- a defect in components - the problem is limited to a few cases;

3- use of components below Apple's standards - the problem may be limited, or more widespread.


This was the explanation I was given. I'm not a technician. Only Apple will know the exact reason(s).


If I had to guess, I'd say that I don't believe it's a design fault, because Apple has an obligation to be very careful about that; I also don't think it's a fault with the component(s) because it seems to be happening all over the planet and doesn't seem to be localized; so I think it's due to the use of component(s) below, or at the limit of, Apple's standards which, when put under extreme stress (higher brightness), end up failing.


I think it's already clear to everyone that this is a design or manufacturing defect in this Apple model.


So let's hope that Apple takes on this construction problem and repairs it or at least contributes part of the cost of the (overly expensive) repair of our computers.


If it were a car, surely all our computers would be called into the workshop to replace the component that has broken down or is in the process of breaking down.


As it's a computer... let's hope that Apple will behave in a way that suits its customers, who believe in the above-average Apple standard...


So keep presenting your cases to Apple.

Dec 29, 2023 7:00 AM in response to latVm

I have this problem also, the lines flicker with mine. It occured while I kept my computer stationary without moving it at all. It's clearly a defect with the display because it happens without a cause. Apple should offer a free fix to people who have these lines regardless of warranty status. I can't pay the 700$ currently and it's ruining my computing experience.

Dec 20, 2023 1:54 AM in response to latVm

The exact same issue is happening to my iMac 2021. I purchased it new in December 2021 in Denpasar, Indonesia, and it has worked perfectly for 2 years. I have taken the utmost care of it - no damage at all.


Suddenly, the bottom half of the screen filled with horizontal black lines. This happened about a week ago, and they went away. It happened again once more, before disappearing. Now they are back and not disappearing after shutting down and turning on again.


I can't believe that it is a coincidence that it is happening to so many people almost exactly 2 years after purchase.


Apple, we need you to investigate this, and to deal with this fairly.


There are only going to be more and more people with this problem.





May 21, 2024 2:37 PM in response to Newcompguy12

Hey everyone! I have a great news.


Thanks to all of you and the thread creator for the evidence, and thanks to Apple for the integrity and standing behind their products.


I was able to get authorization for my case for repair as they are willing to honor it for repair beyond the warranty.


I am now able to go to the store and have it fixed without cost. Will confirm once it's done but I got verified by customer service that I can take it in.


.


Jan 20, 2024 12:24 AM in response to latVm

Exact same issue popped up on my 2021 M1 24" iMac this week. Purchased it back in April 2022, so a little under 2 years. I have it connected to a secondary monitor, which works fine. Only the main iMac display's showing this issue. Have also tried resetting the iMac which didn't work.


Have an appointment scheduled at the Genius Bar in Singapore tomorrow, which I plan to cancel. There's no point bringing my device there only to be told to pay upwards of $800 to get a screen replacement done when I can get a Mac mini for the same price. Everyone in my family is on the apple ecosystem, including MacBooks and Mac minis because because we trust in the quality of Apple products so this happening is just shocking.

Apr 15, 2024 9:08 AM in response to latVm

Just stumbled upon this thread. It happened to me today.


I can’t believe the similarities too - approx 2 years of use, abrupt development of vertical lines, scorching heat on top corner of the screen.


I called Apple support and asked if this was a common occurrence, and was told that they have gotten calls about it.


I think it would raise awareness around the issue if we called to report en masse.


800 186 1087 (toll-free, if anyone needs it).

Dec 19, 2023 8:02 PM in response to SonnyB168

Probably their software updated caused this problem, no one reported similar kind of issue with imac24 inch for first 2 years. Now many from different parts of the world having this issue, it's exactly happenings in same spot for all the users. Apple should be made accountable. Clearly the problem is from their product side.

Dec 19, 2023 5:19 AM in response to latVm

I’ve been having the very same problem for a very well maintained 24” iMac M1 purchased in July 2021. This is very clearly a manufacturing defect. There’s no reason for a lot of people to have this issue pop out of nowhere exactly 2 years later. How do we go about claiming manufacturing defect? Any advice would be valuable. Ain’t no way am I going to pay 600+ dollars for a defect that took only 2 years to pop up.

Jan 24, 2024 6:35 AM in response to latVm

I've got the same issue too, purchased my iMac in August 2021. The lines started appearing November last year, about 2 years after the purchase.


Brought my iMac to the apple store and yes they offered a screen replacement which cost about SGD$900+

decided to not go with it as the lines are only at the bottom of the screen, hoping it wouldn't spread even further.


As you can see from the pictures attached, the black horizontal lines started off very faint and fine, it got darker the very next day, then about a month later it spiked suddenly. The lines would often flicker on and off too.



I've read multiple forums and threads on why is this happening and it seems like the only solution is to get an external display (which I did and it was fine on the external display). It also seems that most people are experiencing it 2 years after getting their iMac, coincidence or no?


This situation has really made me loose trust in Apple's product.

Please investigate this.



Apr 13, 2024 4:34 PM in response to latVm

TOO HOT TOO HANDLE


it’s not just happening to me too.


I bought mine in November 2021 and the same thing started happening April 2023.

I immediately made an appointment with the local local Apple service center here in the Philippines and left it with them for almost a week. They told me the same thing to have the display replaced at around US$800 with no guarantee that it would solve the problem. I did not have it replaced because of this.


I wasn’t aware that this thread regarding the display problem was already in the Apple community. Besides all of the symptoms that I’ve read in this thread, has anyone been in been experiencing heat coming from any part of the iMac body? Mine is at the upper right hand corner of my unit. In the beginning, I did start using an external display to be able to use the iMac, however, while I was cleaning the screen of my iMac, I noticed that that top right part was getting discolored and when I touched it, it was really too hot to touch, that it almost burned my finger.

So since this time in about May 2023, my iMac has been a fixture in the house and I haven’t been able to use it since then. Really hoping to see where how this will be handled, this is the first time any of my Apple devices stopped or couldn’t be used in just two years of use.🙏🏽

Oct 22, 2023 4:47 AM in response to hcsitas

I've been to the Apple Store in Shanghai and the repair fee without Apple Care is about RMB 4,891 which is even more than the recycle fee lol. They said that the solution could only be screen replacement and they have no idea why the problem came out. Cuz there are so many user suffering the same problem I wonder if Apple should be responsible for this problem.

Persistent horizontal lines appear on iMac screen

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