Macbook Pro 7.1 - slows down to full stop when charger is disconnected

Lightspeed65

macrumors newbie
Original poster
Oct 1, 2017
10
1
Germany/Ruhr-Area
Hi there,

I am looking for a solution for the following odd behavior of my MBP 7.1 2010. I

The problem:
MBP 7.1, 4 GB RAM, OS 10.11.6, 320 GB HD starts to slow down immediately after disconnecting the charger and letting the book run only on battery. Systems slows down to full stop within 10 to 20 seconds. With wall charger plugged in again, the book runs smoothly and fast.

What have I done until now?
  1. PRAM and SMC reset (of course), no effect
  2. Installed Mavericks and El Capitan fresh and restarted, also on external drives. No effect
  3. Ran AHT twice, full test (german version, don't be alarmed ;-) ). See first two pictures attached. Sensor errors, afaik. But where?
  4. ran activity monitor and saw kernel_task activity rising high after unplugging the charger, getting nominal when charger is replugged. see pic 3.
  5. Ran iStats-Menu. No Problems with fans, temps or sensors detected. All nominal.
  6. Tried this trick, deleting some plist from library. No effect. Reinstalled 10.11.
  7. changed internal HD with SSD. No effect.
My theory:
When wall charger is unplugged, kernel_task is unable to detect sensor readings from cpu or battery and tries to protect cpu from overheating.

Question:
Which sensors might be affected? Where are they?
If battery sensors are failing, is changing the battery the solution?
Logicboard failure?
What to do now and ... ist the macbook pro worth of all the hassle?

I would appreciate advice from all sides - i wouldn't feel good, leaving the Book behind.

Hope, my german accent wasn't too bad :)

Yours ..

Lightspeed65
 

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Lightspeed65

macrumors newbie
Original poster
Oct 1, 2017
10
1
Germany/Ruhr-Area
Additional information:
Ethernet Port does not function. It does not appear in system report. It does not appear in network preferences. Even after clean install.
Maybe it's a hint for further explanation.
 
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Lightspeed65

macrumors newbie
Original poster
Oct 1, 2017
10
1
Germany/Ruhr-Area
Further additional information:
starting the book secure-mode: No problem kernel_task with battery!!
installing windows 10 only: No problem either!!

In my opinion this has to do with the OS, checking sensors. But which sensors?
Does anyone know, if there are sensors within the battery? Can anyone specify which sensors are meant by AHT-error-reports? Does anyone has an idea, what happens inside system, when book changes to battery-mode? Maybe Mac OS checks sensors in special way and is alarmed by circumstances which might harm the system (Overheating)?

Maybe i am becoming a pain in a neck here. But the solution for me seems to be not so far away, when I only would have more knowledge about the sensors and the way, MacOs handles them.

Thanks in advance
 

Fishrrman

macrumors Core
Feb 20, 2009
19,625
6,838
Easy thing to try:

Create a NEW, "empty" account (for testing purposes).
Give it administrative privileges and any name you wish.

DON'T put anything "non-Apple" into it.
You want it to be "bare bones", for test purposes only.

Now, boot and log into the new account.
Do things go as smoothly as they did in "safe mode"?

If so, that points to something (not sure what) in your regular account that is slowing things down, forcing CPU into overdrive, etc.
Further investigation will be needed.
 

Fishrrman

macrumors Core
Feb 20, 2009
19,625
6,838
If it's a 2010, it's no longer worth replacing the motherboard if you think that's the problem.

Really -- time to start shopping for a replacement...
 

Lightspeed65

macrumors newbie
Original poster
Oct 1, 2017
10
1
Germany/Ruhr-Area
Shopping has to wait. Success.
Started to analyze point six of my list from start. Tried a second time, deleting the plist for my book.
Now the book is running perfectly. Istat Menu controls all temps and fans - all nominal. Obviously, i made something wrong during first attempt. Came to it when installing the original OS (10.5.7) by DVD - and the problem disappeared.

So ... after working now for nearly three weeks in a german forum and here on this, one thing is clear: too many people give up too early. To much logic boards are changed without any reason only on spec. And i am a little disappointed about the lack of interest here. Buying new books and LBs seems the only option for the masses. Kernel-Task-problem is widely spread especially with MacBooks upgraded to modern OS-versions.

No offense ..

Greetings
 

kukulu

macrumors newbie
Feb 28, 2018
2
0
Hi Lightspeed65, have the same problem with my Macbook 13" early 2011 (upgraded to SSD and 8GB RAM, High Sierra),
runs fine until I remove the wall charger. Would you mind explaining how to find and remove the plist. I´m searching in many forums without success and don't fully understand the link you posted above (point six)! thank you very much!
 

Lightspeed65

macrumors newbie
Original poster
Oct 1, 2017
10
1
Germany/Ruhr-Area
Hi Kukulu,

try the following:
1. Go to "About this mac" under the apple in the upper left and click on More info
2. Click on system report
3. make a note of what it says after Model Identifier (i.e. Macbook Pro 5.5 or something like that ...)
4. go to your master drive – System -Library – Extensions – IOPlatformPluginFamily.kext -(right-click-mouse-)Contents – Plugins – ACPI_SMC_PlatformPlugin.kext – (right-click-mouse-) Contents – Resources – find the name from your System-report in step 3 (it ends with "...plist) and move it to a folder that you can find again if needed. Be sure, that this plist-file is removed properly. First time i just copied it and the trick had no effect. Could have saved a lot of time ...
3. Restart and you’re done

I don't know exactly why and what is happening when removing this file. In german MacUser-forum we discussed al lot of possibilities. Nearest is, that Apples temperature control since 10.9. became much to aggressive for some older models. In fact, after removing the file, i monitored the Macbook days with temperature and Hardware-monitor-software. There were no problems at all with overheating or fans out of control. Everything is running fine since then. The book is even running now with sierra. After such a major update you may need to repeat the procedure or at least verify, that the plist-file hasn't been reinstalled by a system upgrade.

That's all. Feel free to comment or ask if you encounter any problems.
And may your MBP live long and prosper.

Greets

Lightspeed
[doublepost=1519892144][/doublepost]supplement ...

If your Mac doesn't allow removing the plist-file, you need to switch off
System Integrity Protection (SIP) first. Read more here


And again ... problems? I try my best to help.
 

kukulu

macrumors newbie
Feb 28, 2018
2
0
Thanks Lightspeed65!
Found it, I seem to have been in the wrong library folder, not under system.
Deleted and testing now! Awesome.
Thanks
 
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