iMac power problem

[frankie big face]

Reset the SMU:

http://support.apple.com/kb/HT1767?view ... cale=en_US

[Caravan Ray]

Reset the SMU:

http://support.apple.com/kb/HT1767?view ... cale=en_US

Done it repeatedly. No good.

[AJOwens]

I know nothing about Macs, but I love a good mystery.

One page I consulted seemed to think it was very important to unplug the power cord at the unit, not at the wall outlet. They didn't say why.
http://forums.macrumors.com/showthread.php?t=987528

Another suggested that depending on your model, the System Management reset may be triggered by an ambient light sensor when you unplug the unit.
http://www.justanswer.com/mac-computers ... won-t.html

So I gotta ask: Which end of the power cord are you unplugging when you try the fix that doesn't work?

[Caravan Ray]

I know nothing about Macs, but I love a good mystery.

One page I consulted seemed to think it was very important to unplug the power cord at the unit, not at the wall outlet. They didn't say why.
http://forums.macrumors.com/showthread.php?t=987528

Another suggested that depending on your model, the System Management reset may be triggered by an ambient light sensor when you unplug the unit.
http://www.justanswer.com/mac-computers ... won-t.html

So I gotta ask: Which end of the power cord are you unplugging when you try the fix that doesn't work?

I think I have pretty much tried every combination and permutation.
I have been trawling the various mac user forums for months now and found a lot of different variations of cord pulling and button pushing. Tried all of them.

I think there is just something wrong with whatever does the 'reset' thing. I have found in some of those forums comments from people with what sounds like exactly the same problem

[AJOwens]

OK, here's a wild shot. Inspect the AC receptacle area to see if you can find a light sensor. If so, try cleaning it. God knows what kind of gunk could be stuck there!

[fluffy]

I know nothing about Macs, but I love a good mystery.

One page I consulted seemed to think it was very important to unplug the power cord at the unit, not at the wall outlet. They didn't say why.
http://forums.macrumors.com/showthread.php?t=987528

Because computers are apparently products of voodoo and not science/engineering. There is absolutely no reason that would make any difference whatsoever.

If it's not the PRAM or the SMU, maybe it's the PRAM battery? If you can get the darn thing open try replacing it.

[AJOwens]

These days you just never know. I still remember my surprise when I learned that my Windows speaker settings were disabled because the the sound card jack wasn't occupied.