MBP A1286 2011/2012 Stuck in sleep!

[mbates14]

Someone brought me this macbook to take a look at. It has a strange problem I cannot figure out.

I apply power, it will chime and the screen will light up grayish/white for a second, then it goes black. It will stay black until the login screen. From there, it just goes to sleep with the breathing white light.

If i hit power, screen lights up and shows login screen sometimes. sometimes not, and you need a flashlight to see it. This will stay for 5 seconds and then it goes back to sleep again.

I tried another power brick, same thing. the battery is charging. I decided to remove the logic board and check for any spill damage, and there is none.

I tried zapping PRAM, resetting PMU, etc. no difference. Even removed the battery and power for awhile.

Tried recovery mode, it will still go black in recovery mode and into sleep. if i hit power, i see the recovery screen for a few seconds and out it goes again. Removing the HDD has no difference either. It will still chime and go grey, then black.

any ideas?

 

[DeltaMac]

Can you boot into single-user mode? Restart while holding Command-S. You should get a text screen. Let that sit for a couple of minutes. It should not change (go black). You can test the hard drive on that screen, using the fsck command. If that works OK, type reboot, and hold Command-V, which will take you to the same screen, but continues to show the services that start up during boot (that startup is called "verbose mode" )

If your MBPro always goes to sleep (the sleep light "breathes", but is NOT a steady brightness), then I might suspect the keyboard/power button.

What happens if you have an external USB (wired) keyboard plugged in?
Same response?
What happens when you press any key on that external keyboard?
Does the sleep light stop blinking, at least for a few seconds? Does the light EVER go completely off?

 

[mbates14]

The internal mouse/keyboard responds. I know this for a fact, as on the login screen I can move the mouse and type in the password box before it shuts off and goes into sleep.

The light breaths as my post had clearly stated. it never goes completely out unless i press and hold the power button to shut it off.

pressing a key, or mouse will not wake it up. I have to press the power button again to wake it up. but it only stays awake for 5 seconds or so and goes back to sleep. I can zap the PRAM, which means the keyboard is working.

I did not try single user or anything of that nature yet. Also unhooking the ribbon cable to the keyboard makes no difference, still goes to sleep. Unhooking the LCD, still goes to sleep.

 

[mbates14]

Command-S made no difference. its still a black screen no video. I can hear the HDD booting though. It always has, and video never comes back until I reach the login screen but only 5 seconds before it goes into sleep.

 

[mbates14]

After screwing with it, it finally stayed on at the login screen. Never shut back off. but after a bit, it froze up no mouse movement or anything.

so the LB is bad.

 

[DeltaMac]

You may be correct about a bad logic board.
Be sure to try swapping the RAM. Try other chips if you have them available, or just swapping the chips between the slots.

 

[mbates14]

been there done that.