Display Falls Off After Repair - New Adhesive Not Sticking Properly

@Adam Atkinson - I don't use anything to scrape the glass, just my finger wrapped with a lint free cloth dampened with Goof Off/GooGone. If the tape is still left I use my finger nail to lift the edge (not the black tape!!)

Sometimes it’s the approach you take not the parts failure. Heat and pressure are very important here.

This just happened to me for the first time. Funnily enough, this is the first time I bought ifixit strips (normally I get them on Amazon) and months later, their screen fell off and is damaged. The adhesive is still stuck to the case and all the old adhesive was cleaned off. I've done hundreds of iMacs and only ifixit adhesive strips have caused this issue for me.

@judahorion - There are a few things that can get you besides an oily surface. The tapes need to be stored in an air tight bag as the adhesive can dry out and clearly the stock shouldn't be old. FYI there are only a few sources for the die-cut tapes.

Generally iFixit's stock is fresh, so its possible you got one that got stuck in the back of the bin. That can also happen from any seller.

Even still I do find heat and a J roller makes a big difference!

I’ve seen a few failed display re-attachment. You need to heat both the case and display so the adhesive is more effective in its adhesion (more so in the winter). You also need a J roller to help press the displays edge down.

I’ve repaired quite a few iMac’s and I you do need to be diligent as an incomplete bond will do you in.

There is no difference between the 2015 & 2017 strips as far as their adhesion! The only difference is a slot cut for the microphone pickup hidden behind the panel.

Just like painting you need to prepare the surface properly. grease and oil will interfere with the tapes ability to adhere, and depending on the temp of the hardware and air the cold will also mess things up.

Following the steps I outlined above you shouldn't have had any problems!

It's a bit late for that, the device is bricked - the screen falling broke the motherboard - the cost of repair from Apple is more than a brand new M1 iMac.

In regards to adhesion - I used 99.9% isopropyl alcohol and cleaned it as instructed. After taking the device to Apple they were unaware that the strips were aftermarket and put on by me. They did notice how the lower part appeared to look odd (the part I cut for the microphone) but they thought this just ripped off as the screen fell.

If the strips were fine, why do iFixit advise on the guide not to use the wrong strips for the wrong device? They specifically provide different strips for the different devices. If it made no difference, A. Why would they provide different ones and B. Why would they not just tell you to cut them.

@alex_rhodes - To mess you up! Not really!

The reason is very simple! Apple altered the way they placed the microphone so using the old tape blocked the needed gap for the microphone hole. As such they made a new part number for the newer designed tape (cut differently).

Now the only risk is tapes age as like your potato chips! There is an expiration date as the oil in the potato chips can go rancid after a few months.

Here, the volatiles that make the tape sticky can dry out. So it's important the tapes are in a vacuum sealed bag and kept in a cool environment. This is true for any tape.