Chosen Solution
My wife’s iMac 20" Core 2 Duo (A1224 - EMC2210) started to present a strange problem. She was working normally when the screen suddenly turned white. She tried turn off the iMac and could not. We took all his cables, turned off the power cord and waited for about 30 minutes. Then I reconnected everything and iMac turn on normally. It worked for about 15/20 minutes and then the white screen again. The iMac is fully locked, does not turn off, does not respond to any command, nothing … That’s when I decided to open it and see the LEDs indicators. At first the iMac turn on normally and about 15/20 minutes of use… again white screen, but before that I realized that, the LEDs all went out and started to light in sequence (same as the boot, but the iMac was not restarting), the 3 first LEDs are on, and the last one off. And the screen went white. So what can be … the LCD ??? The Inveter ??? Or something worse ?! Live long and prosper, Marcelo Magalhães Brasil - RJ - Rio de Janeiro
See if you can discern the desktop on the screen by holding a flashlight at an angle to the screen. If so then replace the inverter: iMac Intel 20" EMC 2133 and 2210 Inverter Replacement iMac Intel 20" EMC 2133 and 2210 Power Supply Replacement But this is a strange problem. The white screen usually indicates a failing hard drive but the restart points to a failing PSU. The power to the PSU may be going causing the white screen and then cascades into a restart. Know issues on this model are failure of the PSU, inverter, hard drive and GPU, in that order. Personally I’d start with the PSU.
You may want to review this IFIXIT guide which explains what the onboard diagnostic LED’s mean: iMac Intel 24" EMC 2134 and 2211 Diagnostic LED’s. Jump down to Step7.
start it up safe mode and see how much memory you have on the hard drive if it’s almost full it would cause this problem
