PRAM/CMOS battery?? Quick tip and question!

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Level 1

8 points

PRAM/CMOS battery?? Quick tip and question!

Hi!

I have a MacBook Pro8,1 (early 2011) which I am typing this on. Works great without anything noteable in the system logs or any problems. This was my sisters MacBook and my brother spilled soda on it. She was told at the Apple store that it would cost $750 (flat rate) to repair it even under apple care (for good reasons as it was water damage). To make a long story short, I was able to clean it up over a course of days, and it is up and running. My brother bought her a new MacBook and when it wasent working I said I would buy it from her as I am sure it could be fixed for much less.

The MacBook works great execpt that it will not charge the battery if the system is runs out of battery. If I leave it in sleep mode and do not use it for days or ig I do not have the charger plugged in and it dies, it will not charge after you place the charger back in; it will NOT show a light on the charger and the battery lights will still show that it is dead and not charging after hours. At some point I got lucky and saw the green ligh on the charger but will still not charge or power on at all.

Here is my quick tip based on much trial and error and the only think that will work and get it back up to normal status:

1) After being properly grounded and straped to the chasis of my desktop,

2) Remove the screws on the Mac book,

3) Remove the battery cable with my finger nail

4) Remove the RAM

5) Place the cable for the battery back in

6) Put the charger cable back in

7) Start the Mac - It will power on at this point but just beep at you that there is no RAM - The charger cable will be green if you did not have any lights on it too.

8) I power it off, place the RAM back in and start it up BUT it will not charge until I reset the SMC and will only reset the SMC if I did the steps above in that order (Press Shift+Control+Option (not Command!!) and the power button at the same time for 3 seconds and then let them go at the same time (very important to do all at the same time)).

At this point the charger cable turns amber and begins charging again and everything returns to full working, normal, non-problematic status unless it runs out of battery again (Note: not sure if necessary but I always clear out the PRAM too before actually booting and I boot in verbose or single user to do an fsck).

Thats my quick tip. My question is, the SMC seems to get corrupt or deleted when no power or battery is left on the MacBook. I have read different contradicting information on wether or not there is a PRAM/SMC/CMOS battery that would normally hold this settings (SMC) even in the event of power rundown or failure (just like CMOS). Is there such a battery or anything else that prevents these settings from having to be reset if no power or battery is available on the MacBook???

For those wondering, battery is fine - lasts for hours and I did replace the RAM for known good MacBook RAM and with new good (but not apple branded) RAM of the same type with the same results, thus the RAM is fine.

I am happy with the results and if I do not think I will be using the MacBook for days, I can just turn it off instead of sleep. But fixing this would make it a perfectly normal MacBook and I also wanted to post the procedures on top in hopes it helps someone else in the same boat.

Thanks,

Art

Posted on Mar 15, 2013 12:55 PM

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Answer 1

projectx2501 Author

Level 1

8 points

Mar 15, 2013 1:01 PM in response to projectx2501

Oh, an edit on my last post, step 5 and 6 and transposed - Put the charger cable and start the Mac with getting POST errors due to the lack of RAM. Then put the back the RAM (obviously) and the battery cable. then proceed with the rest of the steps.

Thanks,

Art

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Answer 2

Mar 15, 2013 1:34 PM in response to projectx2501

No PRAM battery on unibody MBPs.

From what I've seen constantly here, MBPs who's batteries have been left to die completely for a few days seem to have an issue coming back up for some reason. They also experience the same issues as you where the charger won't charge or when it won't power up. Seems that if the owner leave it plugged in for a while, all of a sudden it starts working. Ya, weird, I know...

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Answer 3

projectx2501 Author

Level 1

8 points

Mar 15, 2013 1:58 PM in response to SwankPeRFection

I noticed that too sometimes that if I was too lazy to do the steps above I would just leave it plugged in and will eventually hear a chime all of the sudden and then see the apple boot logo. But what I described above brings it back right away. While it takes only 3 minutes, it does require tiny screw drivers and and properly grounging yourself and straping to the chassy (I know, I know, I am probably the only person that considers that a requirement but I rather play it safe than to short out the logic board with static electricity).

I hope them my notes help people who this happens to and need their Mac running right away and not in hours. But I am still wondering if their is some way to do this that does not cause apple care/ Warranty issues (possibly - I dont think it would but I am not sure since RAM is user serviceable but they say the battery is not thus you can upgrade your RAM but you cant touch your battery is what I understand but I could be wrong). Do you know of anything besides holding Shift+Control+Option and the power button to reset the SMC as this will not work if you are not getting power from the PS or the battery?? I am sure there is no jumpers to reset CMOS like in PCs but if there was it would be point less as it would also require you to open up your MacBook...

Thanks again!!

Art

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Answer 4

Mar 15, 2013 2:27 PM in response to projectx2501

Some have had success with holding down power and then plugging in the adapter. Again, it's hit/miss. Seems to be some goofy hardware behavior that normal PCs just don't exhibit. I can take any other laptop known to man and let its battery die, then plug it in and hit the power button and it comes right up. The more I work with Macs the more I realize they're not the wonders hippies make them out to be. lol Don't get me wrong, I like mine, but it's nothing special. I think the one real reason I buy Apple phones and laptops is because of the fit/finish on them. That's about it.

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