Chosen Solution
Hi everyone, When my iMac goes sleep it won’t wake up, instead it will restart. I have tested it with different OS’s, HD’s and RAM modules. I have also replaced the CMOS battery, still no luck. Now I am going to buy a power supply and give that a try. What would you say? Does anyone knows if power supply could be the source of the problem or nothing got to do with it. Thanks for the help in advance! P.S. - Everything else works way it should. Update (09/16/2016) Hi Finally I have replaced the power board but unfortunately it didnt fix the issue :( I guess its related to logic board . Thanks
Have you tried Resetting the SMC? Follow this Apple T/N: Reset the System Management Controller (SMC) on your Mac I would start there.
Power supplies have a second supply for standby. It is low power but keeps certain circuits alive during sleep mode. If that supply stopped working but the primary supply was ok you might get the effect you are seeing. Before replacing it, I would unplug the AC for one minute and then reconnect and try start up and sleep again. If the standby supply has become locked off due to some glitch, the unplugging the AC will allow it to reset. Worth a quick try.
