Replace LCD on iMac

[rice_man]

Has anyone here done this? LCD is out - black screen with blue vertical streaks. I'm fairly certain I have troubleshot it to the LCD. Mainly becasue the stysem is still working and I can use it if I mirror an external monitor through either of the two Thunderbold ports.

Trickiest part other than finding a replacement is prying the old screen off since they are attached with double stick tape. Unplug data and power ribbons and done -right?

Any other tips or suggestions? Should I buy the speciatly plastic tools?

[rtk]

What year iMac? On mine (square framed before they went to the slim version) they're adhered to the frame by magnets. Two suction cups will pull the glass from the frame pretty easily (best to lay it down on a bed when doing this.) Once you pull the glass away.

It sounds like you have a newer iMac, so this video will help to show how to do break the double-sided tape and remove the data and power cables.

https://youtu.be/jKiBMxxlnVE

[rice_man]

2013 A1418 EMC 2742. Yup that's the video I watched.

Anything else I should tend to while it's opened up?

And how does this fail? Seems pretty common after google it.

[Robotron2k84]

Are you sure it’s the display that’s the problem? LCD displays are pretty reliable now.

Sounds like the logic board and display driver is at fault. Possibly a failed connector to the display cable or similar to the old MBP display issue that the solder joints were crap to begin with.

[rice_man]

Are you sure it’s the display that’s the problem? LCD displays are pretty reliable now.

Sounds like the logic board and display driver is at fault. Possibly a failed connector to the display cable or similar to the old MBP display issue that the solder joints were crap to begin with.

Is there a way to troubleshoot / verify this?

So would an external monitor be working as well as sound and bluetooth capabilities (mouse, keyboard) if both logic board and display driver are at fault? This literally failed overnight. Was running when I went to bed last night and wasn't the next morning. I honestly don't know.

I am currently using this computer to reply to this using a mirrored monitor. So as I mentioned earlier - everything works except the main display.

[Robotron2k84]

The fact you see anything at all on the screen suggests it’s not the display, but the components that drive it.

IIRC LED macs are still edge-lit displays and not matrix-lit. That means that if the backlight failed, you wouldn’t see anything at all on the screen. As well, failure modes for IPS displays are regional, not global.

This is upstream of the physical panel. Yes, your system could still be working other than the display.

When my 2008 MBP ultimately failed, years ago and after four logic board swaps, I still could use it as a target drive to boot another Mac, and pull the contents.

[Robotron2k84]

Do you have the ability to run hardware diagnostics?

https://support.apple.com/en-us/HT202731

[rice_man]

I see nothing on the screen at all. I am using an external display plugged into the Thunderbold port. This is what led me to think that the diplay went bad and not a gpu or - driver issue.

What is meant by regional vs global failure?

[Robotron2k84]

Has anyone here done this? LCD is out - black screen with blue vertical streaks.

If the panel had failed, you wouldn’t see anything, including blue vertical streaks.

If you are connected to thunderbolt, you are using external display driver hardware in the second display.

Does DVI/HDMI output still work? Or, are you using a TB dongle?

[rice_man]

Thanks for the conversation Robotron. I've built a few PCs in my day but the mac is foriegn to me.

I am using a Thunderbolt to HDMI cable. This one to be exact

https://smile.amazon.com/gp/product/B0757JWW81/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

[Robotron2k84]

When you use thunderbolt the data is sent from the GPU, back over the PCI bus, out the TB port and rasterized by a display driver in the dongle or monitor. The cable you are using has the driver inside the HDMI-end of the cable.

Do you have the ability to connect to the DVI/HDMI port on the mac? That’ll be more telling than a video connection over a data-line (TB).

Apologies, reading the specs. says your model doesn’t have a dedicated video port other than TB.

Please run the diagnostics as linked a few posts up.

Regional failure is only a section or set of pixels, global is the whole panel. IPS displays use a transistor for each color of each pixel, meaning that you have to take out a lot of them to see a large effect. If something disrupts all of them at once, it’s the controller, not the LCD.

[rice_man]

There is no DV/HDMI port on the mac. Only USB, Thunderbolt and ethernet.

Trying to run the diagnostic but not successful launching it so far as I have no display to tell if it launched let alone make any selections.

it does make sense to me now that this may not be the panel at issue. Thanks for that input or I would have tried to purchase a replacement already.

[Robotron2k84]

If you can’t run the diagnostics on the system, better to take it to an Apple store, where they can run remote diagnostics on the machine and tell you what the problem is. You could even try to call Apple support and see if it can be done over the internet.

If you go and try to replace a logic board and find out it’s a cable or actually is the panel, you will have spent money trying to find the problem and wasting some of it to find the right component to fix. On newer machines, only Apple can replace the system board (>2018) because they have to initialize the T2 processor.

If Apple will do the diagnostics for you, you can narrow it down. If you wanted to have Apple fix the problem, diagnostics are part of the price and are included.

You might even get lucky and they have a repair program (recall) to address the issue. Or, they might even goodwill you a new machine for the repair price, I had that done on a G4 laptop.

[ghostwong]

I have taken off the screen of the iMacs. Look at www. I fixit.com for detail instructions. Here are the hard lesson of life hints.
1) lay out some nice material to "catch the screen" in case you slip. Hit the edge crack the screen,

2) Wedge something solid between the bottom of the mac and the stand. have the screen at -1 to 5 degrees , before you start cutting

3) Ifixit sells a rolling plastic cutter, works great and is part of the tape kit when you reaaemble the screen to the body.

4) After you roll along the right, top, left edge a few times, the tape HAD NOT bee cut through all the way. THe best thing to do is us those "paper credit cards or a think plastic notebook cover" to cut through the rest of the tape. You don't have to worry about severing and connections, Its all tape and adhesive resistance.

5) once you feel all the tape is cut, slowly bring the screen forward, THe lower edge is also taped on. Disconnect the 2 cables, !) monitor signal cable, and the the port to the LCD panel. The LCD panel is ready to be removed, slowly, SLOWLY cut the tape away with the plaice notebook cover or the rolling cutter.

Remember like shooting do NOT LOOSE control of your Firearm, Never loose hold of the LCD panel, once cut loose, place face down on a soft covered surface,

Good luck Mr. Phelps. If you need pointers OM me
.

[ghostwong]

Rice man, the lowest core operation on the mac is "Target Disk mode" when you turn on the mac hold down the "T" key, if you gave no image on the screen use a flash light to look. It could be the back panel illunaamation is out. to test he machine just plug the a thunderbolt cable on the back of the Mac to a mac and if ir mounts you are good. then you have a bad Panel, not worth replacing at Apple of a third party, If you have a working scrap unit , YES!