This is an issue that started today.

Last night I shut down the machine. This morning I switched it on and got the initial sound but not the chime. The sleep indicator light would blink in groups of 3 blinks. I checked the battery. And also tried some tips on the Apple site for troubleshooting a MBP that won't turn on. Anyway, after looking at a couple of forums, I wound up removing and re-seating the memory. Ok, then it works for about 45 minutes, but then the screen went black and again the 3-blinks of the sleep light.

What should I try next in troubleshooting this machine?

I have had no problems in terms of performance or other issues til today. The MBP is from early 2008. There was an iTunes update yesterday and otherwise no new software or updates. Also no external devices plugged in.

However it did have the power supply connected. I did notice this morning that the power supply had come loose from the power strip -- possibly caused by a cat. This is the only thing that seemed to be a variance from usual.


Anyone? Links or tips on MBP diagnostics would be appreciated.

  • 1
    At what point in this process did you discover the MBP was unplugged? Is the problem continuing to happen after the MBP is fully recharged?
    – Dori
    Sep 12, 2010 at 1:12
  • @dori Right after I initially realized that the machine was not starting up and that the charge indicator was not on. And yes the problem continues even with the battery charged. I didn't try re-seating the memory until I had verified the battery charge. I can hear that something is 'on' in the machine when the sleep light blinks. Not sure if I'm hearing fans or the drive.
    – wdypdx22
    Sep 12, 2010 at 7:49
  • 1
    Have you tried removing the battery and turning it on without it? If there’s a problem or a shortcircuit in the charging circuit, that will skip it. (It happened to me on an old Powerbook) Sep 12, 2010 at 20:13
  • 1
    also try posting a similar or identical question on ifixit.com. There are a lot of hardware technician types on there. Sep 12, 2010 at 21:34
  • I have a same problem here since yesterday after update my MBP it's batery just charged 50% after that adapter stop charging and heated so much then yesterday it will not charge anymore and can't turn it on although by adapter attach it.
    – Am1rr3zA
    Sep 12, 2010 at 22:02

2 Answers 2


The blinking is a for of POST (Power On Self Test) and can certainly help diagnose the issue.

As most people are saying it is most likely a RAM issue.

The following documents can help diagnose POST messages and various issues related to your laptop during the boot process:


This happened when one of my RAM slots died. There was nothing I could do but use the other one. Note: if your RAM limit is 2GB, you can put a 2GB stick in one. The total system memory, however, cannot exceed that.

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