Charlie Nancarrow

This issue can also be the EMI filter. This is the actual AC inlet. There are also capacitors and other passive components inside here. If the earth lead from this is also not firmly connected you may get the same buzz shown in this video. Otherwise as others have noted, it is the power supply. You can solve many buzzing issues with reapplication or additonal application of neutral cure silicone or potting compound. You will find quite a bit on there already (those white globs). Just add some more around the transformers, between any larger capacitors that might likely be vibrating against each other. Dont use acidic cure silicone or you will corrode the insides of the machine!

Repairing sockets that come off the logic board is possible, but very specialised work. Unless you have a magnifying lamp and the necessary desoldering and soldering skills, it will be difficult but not impossible.

Mitch has the exact method that works a treat. You don’t need to follow steps 24-37 and also 40-63. Step 51 is the step to remove the camera cable and is needed. Steps 38 and 39 are for the Fan. That is all that is needed. Done quite a few like this.

Be careful not to drop the RAM down the back of the logic board!

By NOT removing all the other stuff you can avoid either damaging it or forgetting to plug in a cable.

You don’t need to remove the power supply, harddrive or logic board to do a RAM upgrade on these machines.

Skip steps 24-37.

You just need to remove the fan. With the fan removed, you can access the RAM and its release tabs sufficiently to remove the RAM and install new RAM.

Also skip steps 41-61

The steps 62-64 are useful above to show you exactly whats going on on the logic board, but you really do NOT need to remove the whole board.

It is a little tricker with the limited space, but you are far less likely to damage other parts of the machine if they are not removed.

I suggest putting the iMac vertically on its side (ideally with someone else holding it), so that when inserting the RAM, it stays in the slot as you clip it back into the socket.

This goes from a 2.5hr repair to less than an hour.

Both, you can’t decide later on. But if you really are pushed for one, do the RAM, or better still the SSD size.

Not sure if the EMI filter will NEVER fail as someone said above. Mine was buzzing and I replaced it and this fixed one of my displays that was buzzing. There are also other causes, including capacitors on the Power Supply board, worn out fan etc.

Often only parts of the logic board go faulty. The logic board in this unit is really a hybrid of several circuits, all running off thunderbolt. You may see that the Display Audio, Display Ethernet works when the display doesn’t and vice versa. The backlight power circuit is also on the logic board. It may have been both parts replaced were faulty, or just the display.

Add the note that it should be lifted from the bottom edge. It is also important not to twist the display by levering up from one corner.

Please update the picture to include the RED BOXED IN AREA that you refer to on all three pictures in this step. I have had a few zaps from these supplies and it is not pleasant.

If the note in this step can be updated to more accurately describe why the notches must be visible, that would be most helpful.

Perhaps written as per “The camera cable (ie the AirPort cable) whilst it can fit in both ways, you WILL cause damage to either the card, the motherboard or both if the orientation is not correct.

The cable MUST be installed so that the notches on one side of the cable are not visible”

The glass is glass Scott. It will shatter if you don't take it straight off. If you lever it open like a door, you will either break off the metal pins that are bonded to the glass, or crack the screen or both.

If you can get a pick in the edge, you can remove it without Suction cups, though they do help to remove it straight off without bending the pins.

If you are just doing the drive, then you can do it all without taking off the Screen completely. You just need to unplug the Inverter cables to lean the screen back then you can remove the drive, replace the drive and close it all up again.

Be aware the drive cables are very short in the 20" model. You will need a drive carrier that places the SSD data and power connectors in a similar location to a 3.5" drive (which these carriers are quite rare). Or get an SATA+Power extension cable for a couple of bucks.

You could do away with a bracket and use double sided foam tape or strong double lock velcro blocks to position a SSD on the back of the iMac.