Chosen Solution
Hi all, First post here looking for some help. I’ve been given iMac by a family member due to it not working. It looks like someone has opened it before, as the cable to screen have been damaged :-( However the iMac turns on but the screen is black. It chimes,as usual hard drive and everything boots up, but no picture. After about 10 seconds the fans go into mega overdrive. I’ve plugged it into an external monitor and the screen appears fine on there. But it doesn’t boot to anything just hangs. I’ve tried resetting the PRAM I think it is, no change. I’ve even tried holding down D upon startup, but the fans are going so mad I don’t want to damage it further. Any ideas what this could be so I could order a part to fix it. I was hoping this could diagnose what the fault would be Any advice would be greatly appreciated. Thanks, James.
What model is this? You can check with the serial number on the bottom of the foot. Go to this page and choose “Browse by product” and enter your serial number. If someone has opened it and you say the the screen cable (LVDS) was damaged, it seems it maybe was not inserted correctly on the logic board side. Also it could be damaged again inserting it incorrectly. If you can open the iMac and tilt the screen so you can see the 4 LED lights beside the LVDS connector you can tell us what light are on. LED 1, 2 and 3 should light up. Then LED 4 should light up and then off. The crazy fan blowing indicates that a cable is not attached correctly, maybe the temp sensor to the hard drive or LCD. Take a look at this guide and check that all the cables are attached. Could be going over the cables again could solve your problem.
