Combo move worked for me
Following an hint found in a post on this same blog a few days ago, I tried doing some experiments with power management unit reset.
…and I think I found a pattern!
Actually neither simple PMU reset nor simple PRAM reset works, but a combination of the two allowed me to go back to glorious performance even if only until the next shutdown.
So, here’s my combo:
. shut the macbook down
. remove the battery and power cable
. hold the power key down for 10 seconds or so
. reconnect the cables and battery
. power up the mac and hit Cmd-Alt-P-R, until the mac reboots.
Et voila’! After this combo my macbook was able to sustain Divx playing + second life sessions heating up to above 70 degrees at 2.0 GHz (as reported by CoreDuoTemp) with fan working correctly and no signs of shutdown.
Note that at next reboot the system will be subject to Random Shutdown again :-/
At this point I’m starting to wonder if it’s a firmware bug more than a physical issue.

September 22nd, 2006 at 2:47 pm
Interesting… A-Mac in Utrecht (Holland) told me to wait for a firmware update… maybe that will help after all!
September 22nd, 2006 at 3:26 pm
Yes I think so…
Let’s hope it comes soon, I cannot stand doing this trick everytime I shutdown the beast!
September 22nd, 2006 at 5:42 pm
I do that every morning, and yes it works, but the next day when i start the mac the screen its black and dont charge the OS X…so i need to do ur combo again…for me works for one session to work, 10 or 14 hours, but when i try to turn on the day after…still the problem…
September 22nd, 2006 at 11:51 pm
Yes, the PMMU reset works for me every time… until I next have the machine go to sleep (e.g. closing the lid to carry it from one meeting to another).
Once it’s gone to sleep, and woken up, inevitably I’ll get the sudden screen goes black, power goes off within 10-20 minutes.
The question has to be asked…
September 23rd, 2006 at 7:33 pm
Unfortunately, this solution did not work for me. I am quite confident that the problem is, for some users at least, in the hardware.
September 23rd, 2006 at 11:13 pm
The pattern of RSS on my machine sounds similar to yours. I’ve found, though, that if I hold down the start button until the white LED flashes and the computer beeps, then I’m good to go until I restart the thing or close the lid. I haven’t needed to fiddle with cables or anything.
September 24th, 2006 at 9:42 am
Mahlered: true, but your cpu will be capped at 1.0 Ghz… I’d like to use some more power
September 24th, 2006 at 9:07 pm
I want to mirror what FruJu in post #4 said. This was exactly my experience.
I reset as stated in the first post, but once it’s gone to sleep, and woken up, inevitably I’ll get the sudden screen goes black, power goes off within 10-20 minutes.
I called AppleCare yesterday (Sat 9-23-06) to get a box for return and repair and the AppleCare rap states this will take 20 business days to fix! A month without my computer! I am outraged at this! Meanwhile Apple will have my computer for a month and the warranty ticks away.
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