Apple Mac Intel 27 Retina 5K – How to fix the display of apple Mac

DISPLAY FIXING PROCEDURE 

Before you start placing strips, remove all of the old adhesive. Use a spudger to scrape up an edge, then peel with your fingers.
Remove all of the remaining adhesive strips from the iMac's frame and display glass.

Start with strip 13, which goes on the right vertical. Before peeling off any backing, line it up against the frame of the iMac to get an idea of where it goes.

Peel the short piece of backing off the back of the strip.

Insert the tip of a spudger into the hole at the top of the strip from the side that still has a backing on it.

With the spudger still poking through the hole in the adhesive strip, push the spudger tip into the corresponding hole in the frame of the iMac.

Using the hole and spudger to anchor the position of the adhesive strip, line the strip up against the right edge, gently pull down against the spudger to ensure the strip is taut, and stick it onto the frame.

Once you're satisfied that the top half of the adhesive strip is neatly aligned, peel the longer piece of backing out from behind the strip.

If the top half isn't aligned properly, you can carefully peel it up and re-stick it before peeling off the lower backing strip. Be sure to use the spudger tip to anchor the top.

Align the lower portion of the strip with the right edge of the frame, and stick it down.

Use your finger to smooth all of strip 13. Make sure it is neatly aligned with the right side of the frame and that it sits flat.

Do not peel off the front adhesive backing yet.

Work your way around the perimeter of the iMac, adding three more adhesive strips in the same manner.

Working counter-clockwise from strip 13, place strip 12 on the top right, strip 11 on the top left, and strip 16 on the left vertical.
These three strips have a hole at each end—always use the smaller hole for alignment for more precise placement.
On the iMac Intel 27" Retina 5K Display, strip 12's blue tabs will not line up with the top antenna in the same way as the regular model. This is perfectly acceptable and won't impact the performance of the strips or antenna.

Strips 14 and 15 will go on the display frame.

Remove the white backing from the back side of strip 14.

With the front-side backing still on, line strip 14 up with the bottom right edge of the rear of the display.

The "L" shaped corner at the end of the strip should fit around the back of the LCD.

Use your fingertips to smooth the adhesive strip from its center out to ensure a good seal with no bubbles or wrinkles.

Repeat the previous 3 steps to place strip 15 on the left side of the bottom edge of the back of the display panel.

Strips 14 and 15 should butt up against each other in the center of the display.

Peel up and remove the backing from strips 15 and 14 on the display.

Peel up and remove the remaining backings from all of the strips around the frame.

Do not fully lower the display in this step; there are still two cables that must be attached. Once you've set the display down, you won't be able to lift it again without damaging the adhesive.

Lay the bottom edge of the display glass against the top of the lower bezel. Be sure to align the edges of the display with the edges of the rear case.

While holding the display panel up with one hand, reach in to reconnect the display data and power cables, as shown in the next step.

Gently insert the display data connector into its socket on the logic board. Be sure to press it straight into the socket, and insert it completely.

Flip the display data connector lock down onto the socket.
Insert the display power connector into its socket on the logic board.

Before sealing the screen in place, you may want to test powering on your iMac to ensure you reconnected everything correctly. Be careful not to touch anything inside while the machine is  powered on.

While pressing the display against its ledge on the lower bezel, lower it down into place.