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Model A1418 / Late 2012 / 2.7 & 2.9 GHz Core i5 or 3.1 GHz Core i7 Processor

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Sleep awake failure and restarts. Is it related to power supply?

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

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crwdns2933315:02crwdne2933315:0

Have you tried Resetting the SMC? Follow this Apple T/N: Reset the System Management Controller (SMC) on your Mac I would start there.

crwdns2934105:0crwdne2934105:0

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crwdns2942205:01crwdne2942205:0:

Hi Dan.

Yes I have reseted the SMC but it didnt help.

Thanks

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934285:0crwdne2934285:0

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.

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Hi Whole Witt.

I have unplugged the AC several times didnt change anything.

I guess replacing the power board is my only option .

I just want to find out whats role of the power board in Sleep Awake cycle before I spend any money .

Thanks

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

I suspect a power issue. If the supply standby power is not working at all it could give you this problem. No guarantee but that is worth a try. If you find the solution, please post it here for others to see.

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

I will go for power supply and post the result here .

Thanks again.

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