[Doc HM]

Just fitted a replacement HDD for a friend into their iMac 21.5in. On these Macs Apple has started using the SMART diagnostics socket on the hd to report temp data etc so the replacement hd needs to match the type originally installed (or so I thought).

Anyway, I've replaced a Seagate Barracuda 320GB 7200 drive with a 500GB version of the same drive. However while everything work fine OS etc wise, the damn hd fan keeps ramping up to max revs.

Any ideas?

[Waragainstsleep]

Service manual only contains a warning about correct installation of the sensor cable with a WD drive. My guess would be that its not installed correctly. I would open it back up and check the sensor at both ends.

[Doc HM]

The cables definitely in. It's hard to get it wrong, one end clips into the smart socket of the drive the other into the "temp" connector on the mobo. Have checked it twice and it's connected fine. Temperature sensor app is showing a steady temp reading off the HD but the fans keep speeding up. Strangely on the first drive SMART reporter reported the drive as failing, which it wasn't. So there's definitely an issue somewhere.

[MacCompuFix]

Unfortunately you must replace the drive with an Apple OEM drive. The only way to get one of these is to take your machine to an Apple Authorized Service Center.

[AKcrab]

Originally Posted by MacCompuFix 

Unfortunately you must replace the drive with an Apple OEM drive. The only way to get one of these is to take your machine to an Apple Authorized Service Center.

I don't think this is true.

[shabbasuraj]

I think your replacement drive is faulty.

Try another?

[Waragainstsleep]

I wouldn't worry about SMART reporting too much unless it comes with matching strange noises or performance issues. The SMART diagnostics are not always accurate, or rather I have seen them report faults on drives which have gone on for years.