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Run a MacBook at full clock speed without a battery

post #1 of 12
Thread Starter 
I purchased a broken MacBook (Santa Rosa) from Ebay several month ago. I use it as a media center connected to my home theater. The MacBook was dropped and had a broken screen and a beat up case. It was always the eye sore of my entertainment center. I recently decided to put it in a custom tiny enclosure witch is nothing more than an attractive external hard drive case. I got it all together and everything is running great...except one tiny detail. The MacBook underclocks itself to 1200 MHz when the battery is not connected. After much research I discovered this was intentional by Apple and all advice given to me was just put the battery back. I don't have room to put the battery back I just have it laying next to the computer causing the same eye sore I had before. There has to be a way to "trick" the computer in thinking the battery is connected. I wouldn't mind it if 1200 MHz was enough raw power to decode HD h.264 but its not. Does anyone know a way to either directly attach the mag safe adapter directly to the battery terminals or somehow short the pins to simulate a connected battery? Or better yet a software solution?
post #2 of 12
I would have assumed that if Apple were making the CPU underclock under certain conditions, it would be while on battery, not plug. Forcing it to underclock when plugged in doesn't make any sense.
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post #3 of 12
Quote:
Originally Posted by addabox View Post

I would have assumed that if Apple were making the CPU underclock under certain conditions, it would be while on battery, not plug. Forcing it to underclock when plugged in doesn't make any sense.

Forced underclock when plugged in with no battery.

Normal clock when on battery.
Normal clock when plugged in with battery in.

Originally Posted by Marvin

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Originally Posted by Marvin

The only thing more insecure than Android’s OS is its userbase.
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post #4 of 12
Quote:
Originally Posted by Tallest Skil View Post

Forced underclock when plugged in with no battery.

Normal clock when on battery.
Normal clock when plugged in with battery in.

Why the underclocking with no battery/plug? It's not like the battery is buffering the power, or something.
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post #5 of 12
Thread Starter 
My understanding is that the battery essentially acts as a large capacitor. What I don't understand is why the power adapter can't compensate for power fluctuations? My thought is to short the pins on the terminal to simulate a connection?
post #6 of 12
Quote:
Originally Posted by yeroc3103 View Post

My understanding is that the battery essentially acts as a large capacitor. What I don't understand is why the power adapter can't compensate for power fluctuations? My thought is to short the pins on the terminal to simulate a connection?

Interesting, I had no idea that was going on. My guess, though, is that there's actual logical process on that bus (since any capacitor-like function would need regulation and surely be included in the general power management routines), so that just shorting out the pins won't work. Worse, you might damage something, since if the system sees even an unneeded battery as a reserve it's going to be expecting to route power accordingly, not just into a short condition.

Any chance you could find a small batt of the right voltage that would fit into your enclosure? Or better, maybe someone who can do the circuit calculation better than I could recommend an actual capacitor sized to match whatever the battery was doing?

EDIT: Aha, I looked around a bit, and seems you may be out of luck. The Apple support page explains that when being stressed, the system actually needs more power than the AC adapter can provide, so it pulls from the battery. So it appears that sustained h.264 decoding on that model may take more juice than the mains can give you-- which means any battery work arounds would just risk killing your motherboard.
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post #7 of 12

I may not be an expert, but for me that makes no sense at all. If the Macbook actually needed more power than the AC adapter can provide, then it would never charge while powered on.

 

If the AC Adapter alone couldn't provide the necessary energy to make the Macbook work, how could it charge the battery while the power is on and the battery is being used? 

 

There's more. Windows actually works at full speed on a Macbook without the battery, using the AC adapter.

 

There must be a way to bypass the forced downclock.

post #8 of 12
Originally Posted by interrock View Post
There's more. Windows actually works at full speed on a Macbook without the battery, using the AC adapter.

 

There must be a way to bypass the forced downclock.

 

Sure, but don't come whining to Apple when you break your laptop.

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post #9 of 12
Quote:
Originally Posted by Tallest Skil View Post

 

Sure, but don't come whining to Apple when you break your laptop.

 

It's ALREADY broken ! :)

That was the whole point of the thread! (and piqued my interest for the same reasons as the OP... too bad nobody has figured out a solution yet.)

From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, "Look at that!" -...
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post #10 of 12

Hey guys, I finally managed to make it work!! Here's how:

 

1- First download these two kext files:

SleepEnabler.kext.zip

NullCPUPowerManagement (32-/64-bit)

 

2- Go to /System/Library/Extensions

 

3- Make a backup of AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext and then delete it from this folder

 

4- Add here the two kext files you've downloaded earlier

 

5- Open Terminal and do the following:

 

cd /System/Library/Extensions

sudo chown -R root:wheel SleepEnabler.kext

sudo chmod -R 755 SleepEnabler.kext

sudo chown -R root:wheel NullCPUPowerManagement.kext

sudo chmod -R 755 NullCPUPowerManagement.kext


6- Reboot and you're done!

 

 

If the computer doesn't boot, do this:

 

1. Hold down the option key while powering on


2. Choose [Recovery HD]


3. Open Terminal


4. Do the following:

 

cd /Volumes/[volumename]/System/Library/Extensions

rm -rf SleepEnabler.kext

rm -rf NullCPUPowerManagement.kext

 

5- Restart

 

6- Put AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext back in the /System/Library/Extensions folder 

 

Voilá!

 

 

The fans are still on high and I'm not sure the CPU is working properly, but the slowdown is totally gone. Is good to use a software like CoolBook to manage the energy resources from now on.

 

 

Source: http://forums.macrumors.com/showthread.php?t=1401957


Edited by interrock - 3/17/13 at 10:40am
post #11 of 12
Quote:
Originally Posted by Tallest Skil View Post

 

Sure, but don't come whining to Apple when you break your laptop.

 

What's the use of a Macbook that's already broken?

From here I'd have five options:

 

1- Pay for the logic board replacement (costs around $900 here in Brazil)

2- Sell parts on eBay

3- Stick with Windows

4- Make it work without the battery somehow

5- Set fire on it and post a video on youtube

 

What would you do?  1biggrin.gif

post #12 of 12

Did some tests with CPUTest and it turned out ok. The max temperature was 52ºC. 

 

Still couldn't make the sleep function to work, even with the SleepEnabler.kext. I'll turn off the sleep option until i find a workaround for this. 

 

I'll keep you updated if something new happens. 

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