Replacing Hard Drive Help (not instructions) and compatibility issue question

[Jondrums]

So, I have two questions pertaining to the replacement of imac (21.5 and 27") hard drives.

1) Upon removing glass and disconnecting lcd I don't know how to (re)plug in all the cables. Does anyone have any specific diagrams or instructions for locating the correct cables and plugging them into the correct spots.
- I purchased the imacs without hard drives and i believe the auction people failed to (re)attach the cables after removing the hard drives.

2)I have read several articles about compatibility issues with the late 2009 to mid 2010 imacs regarding upgrading hard drives. Each post has said to (upon removing original hdd) take note of the brand either Western Digital or Seagate and purchase new hard drives of that brand to avoid temperature sensor/fan issues. The problem is that these 2 imacs do not have hdd's currently, so I do not know what brand to purchase. Is there any way to discern which brand based off the following information:

21.5" 3.06 Core i3 mid 2010 (2389 EMC)
and
27" 2.66 Core i5 late 2009 (2374 EMC)

thanks for any help!

 

[chscag]

The first question is easy to answer. Go to iFixit: The free repair manual and lookup replacing the hard drive for your model(s) iMac. They'll have step by step instructions including the diagrams.

Your second question is more difficult to answer because on some iMac models Apple used proprietary hard drives with special firmware and SATA cables. Even though those drives were manufactured by Seagate and Western Digital, they were made to Apple's specs. An ordinary hard drive as a replacement could cause the hard drive temperature sensors to malfunction resulting in a run away hard drive fan.

There are work arounds which have been posted. I'll leave that up to you to dig out and if you wish, to use one of them. The other alternative is to have Apple install the hard drives in both machines. Of course that will be at the cost of the new drives plus labor.