Quick video of 21" tear down. There is no way I would want to attempt to replace the ram myself after watching this, but it is possible after breaking the glue ...
http://blog.macsales.com/15932-what-does-it-take-to-upgrade-a-2012-imac-21-5
Got a question for you. Or if not you, anyone who reads this and knows the answer.
Say I were to get a 27" iMac, and I want to upgrade the storage from, say, an HDD to an SSD at some point in the future. Do I have to sell my iMac and buy an entirely new machine, or can I take it to a certified Apple repair shop, and get them to swap one out for me without voiding my warranty? Can I provide my own drive, or do I have to buy one directly from Apple?