Shut down the imac and unplug power cable.
Place the iMac on a smooth and clean surface, and put it face down (the handle on the table)

Using a coin (or a big flat-headed screwdriver) free the door of RAM bay by turning the lock ~90° CCW

Open RAM bay door

Before plugging the RAM DIMM module ensure that plastic hooks –on RAM slot sides– are open.

Put the DIMM module in place, taking care of its direction

Once the module has been placed press it carefully but firmly with fingers close to DIMM edges. This should cause the white plastic hooks to come up and lock the DIMM module.

Verify the correctness of DIMM locking.
We can now close back the iMac.

© and credits

All material used is orginal and specifically produced for faqintosh.com

⌘ Marco Balestra (operator, author)