iMac 21.5 Mid 2011 screen artifacts / pixel problem

[XM22]

Hi, i've been experiencing artifacts / pixel problem on my iMac for a few weeks now. Initially i thought the graphics card was failing, however when I ran the Apple Hardware Test, I was shown the message (4MOT/4/40000003: HDD-1451), which pointed to a Fan motor problem causing the hard drive to be failing. I've since installed the SSD Fan Control and the pixel problem is showing up less frequently.

Im wondering how accurate the Apple Hardware Test is and also if a failing Hard Drive will cause the screen to have artifacts / pixel problem? Thanks

 

[chscag]

Welcome to our forums.

I doubt a fan problem is causing the pixeling. Your 2011 iMac has three fans: Hard Drive, Optical Drive, and CPU. That AHT message is actually referring to the hard drive temperature sensor. You're probably correct about the graphics card failing. Keep your eye on it.

 

[harryb2448]

Any chance the hard drive has been changed without a heat sensor kit, necessitating Fan Control software?


https://eshop.macsales.com/item/OWC/DIDIMACHDD11/

 

[XM22]

Any chance the hard drive has been changed without a heat sensor kit, necessitating Fan Control software?


https://eshop.macsales.com/item/OWC/DIDIMACHDD11/

Hi nope the hard drive has never been replaced. The one and only time i service this iMac was for optical drive issue. Everything was done by Apple, hence no 3rd party hardware installed.

Also i realise that the artifacts / pixel only appear on the desktop/finder screen. Will never appear when I'm using full screen browser or watching movie.

 

[XM22]

Welcome to our forums.

I doubt a fan problem is causing the pixeling. Your 2011 iMac has three fans: Hard Drive, Optical Drive, and CPU. That AHT message is actually referring to the hard drive temperature sensor. You're probably correct about the graphics card failing. Keep your eye on it.

I pray it isn't the graphics card issue as it is very expensive to fix. Wondering why AHT isn't able to detect it if it was indeed graphics card issue.

 

[ferrarr]

Make an appointment with Apple Store Genius Bar closest to you. Let them look at it, and then decide, if the fix is worth it. I also believe it is the drive failing, which you may want to explore the do-it-yourself route, https://www.ifixit.com/Device/iMac_Intel_21.5"_EMC_2428.