Resetting PMU, I think?

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Level 4

2,826 points

Resetting PMU, I think?

Hello,

A friend of mine has a MacBook Pro which for the most part works very well. There is only one major issue with it, and that is it won't fall asleep. Even though the settings are correctly set to have the laptop go to sleep after 10 minutes it never falls asleep. It will simply stay on until the battery runs out and the then goes into hibernation/deep sleep mode. This was an issue before and she took it to the Genius Bar, there she said they did something where they took the battery out, left the power cord plugged in and pressed some button combination. She's sure it included something in the lower left hand corner of the keyboard (ctrl, shift, option, command) but she's not sure what. I think they reset the PMU, but I don't know if they did that or reset the SMC or the PRAM. Does anyone know what they did, 'cause whatever it is it worked for quite a while, so that I can try it for her again? Thanks so much.

-NifflerX

MacBook, Mac OS X (10.4.11)

Posted on Jan 4, 2011 5:19 AM

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Answer 1

eww

Level 9

53,052 points

Jan 4, 2011 5:42 AM in response to nifflerX

It was the SMC:

http://support.apple.com/kb/HT3964

There isn't a PMU in an Intel Mac; the SMC is its rough equivalent.

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Answer 2

nifflerX Author

Level 4

2,826 points

Jan 4, 2011 6:49 AM in response to eww

Thank you very much for the quick reply. The SMC reset page you sent me says that to reset the SMC you must unplug the power adapter and then hold down the power button, but my friend is certain the power adapter was plugged in when the Genius Bar guy worked on her computer. Is there some other operation that could take place with the power adapter plugged in that would fix a problem like this? Maybe I'm just completely wrong with the SMC thing and the Genius Bar guy did something else? Thanks again.

-NifflerX

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Answer 3

nifflerX Author

Level 4

2,826 points

Jan 8, 2011 8:59 AM in response to eww

Hi,

Not surprisingly, you were right and I found the old receipt that said what the Genius Bar did, and they reset the SMC. However, it doesn't seem to have worked. I followed the instructions on the site you posted, then I did a test. I set the sleep settings (in System Preferences) to 2 minutes and left the computer alone. The display dimmed as expected and turned off after 2 minutes but the computer was not asleep. If I touched the trackpad the computer's screen lit back up right away.

The computer can sleep, if I go to the apple menu and choose sleep it does sleep and requires a key press to wake up, not just touching the trackpad. I did all these tests with the computer plugged in.

Is there anything else I can try to get the computer to fall asleep when it's suppose to. It becomes an issue when the computer is left open accidently and then when I come back to it the battery is completely drained.

Thanks again for all your help.

-NifflerX

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Answer 4

eww

Level 9

53,052 points

Jan 8, 2011 4:32 PM in response to nifflerX

Create a new user account, log into it, open Energy Saver Preferences, click the Battery tab, set Computer Sleep to one minute and Display Sleep to Never, and see whether the machine sleeps as scheduled in that account. Post back with results.

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Answer 5

nifflerX Author

Level 4

2,826 points

Jan 9, 2011 8:36 AM in response to eww

Hi,

I went and created a new standard account, logged into that account and set the settings up as you said. After a minute the screen went black but everything came back with a touch of the track pad. I tried letting it fall asleep again including letting it sit with no interaction for 2 minutes and the results were different. At that point it actually fell asleep and required a keyboard press to wake up. Does this mean I need to clear our my energy preferences at ~/Library/<some file> for the main account? If so, which files, if not is there something else I can do? Thanks again so much for all the help.

-NifflerX

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Answer 6

eww

Level 9

53,052 points

Jan 9, 2011 9:29 AM in response to nifflerX

Before you do anything else, repeat the test in that new account, but this time watch the sleep light on the front of the machine when the display goes dark after one minute. I'm guessing the light will come on steadily (not pulsing), and remain that way for somewhere between ten and thirty seconds, and then will begin to pulse. See whether I'm correct, and post back with your findings.

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Answer 7

nifflerX Author

Level 4

2,826 points

Jan 10, 2011 6:22 PM in response to eww

Hi,

Thanks again for the post, here are the results of the test.

Once the screen dimmed the light came on, as you expected, however it stayed on, no pulsing, for 1 minute and 45 seconds. At that point the light started to pulse and the computer was asleep (required a key press to wake up). I ran the test a second time and this time it didn't pulse for 3 minutes. I ran it a third time and the third time it pulsed after 1 minute and 40 seconds. What should I try next? Thanks so much.

-NifflerX

Message was edited by: nifflerX

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Answer 8

eww

Level 9

53,052 points

Jan 10, 2011 6:42 PM in response to nifflerX

What's supposed to be happening while the light is on steadily is that the contents of RAM are being written to the hard drive. But 1:45 or 1:30 seems much too long for that to take, unless you have an awful lot of RAM in use and a slow hard drive. If it takes that long right after you've started up the computer and before you've opened any applications (so that very little RAM is in use), I have to think the hard drive must be impaired. What does Disk Utility say about the SMART status of the drive?

Better still, what does [SMART Utility|http://www.volitans-software.com/smart_utility.php] say about it?

Message was edited by: eww

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Answer 9

nifflerX Author

Level 4

2,826 points

Feb 1, 2011 5:46 AM in response to eww

Hi,

Sorry for the delay in getting back to you. I ran Disk Utility's Verify Disk and got the following results:
"The volume appears to be OK."

I also ran SMART Utility and got that the Overall SMART Status is: PASSED.

Anything I should try next? Thanks again for helping me.

-NifflerX

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