PowerBook G4/550 won't power up, please help...

[Tsaitsai]

Greeting,
I have a dead PowerBook G4/550 that won't power up quite completely.

I tried to reset PMU (control+option+p+r), and the few times when it powered up (just fine with the chime sound and the normal gray screen), but then the powerbook would freeze few minutes later. I have to press the reset button (at the back of the unit) to shut it down, but then I won't be able to power up the laptop at all. I tried to ignore the issue and returned few hours later to attempt to start the laptop, sometimes it powered up to a black screen (attached an external monitor to nothing) and sometimes it wouldn't power up at all (dead as a rock). Then there was one time I powered up the thing and ran the "hardware diagnostic" CD (before it freezes) and everything showed normal (logic board, screen, memory, etc).

So what could be the problem? Bad logic board? Power Management Unit problem? Dead pram battery? Any hep would be greatly appreciated. Thanks in advance.

Tsai

p.s. the AC adaptor is connected and the battery hold only 2 minutes of charge.

 

[Ric]

Hi there and welcome !

Can I just check, you said that you have reset the PMU...did you mean the PRAM ?

Have a quick read of this if you haven't and try resetting the PMU...

http://docs.info.apple.com/article.html?artnum=14449

regards

Ric

 

[Tsaitsai]

Hi,
I did perform a PMU reset, but after the reset the laptop still doesn't not power up at all. It's just a sitting duck....

Tsai

 

[Ric]

Hi Tsai,

apologies for the delay in replying...

Have you got any further ? Or is it still a dead duck ?

regards

Ric

 

[Tsaitsai]

The powerbook remained dead. Although today I pressed the power button with "ctrl" and command buttons and it actually started in a normal fashion! However, after I logged into my account, it crashed few seconds later whiling trying to get into my desktop scree.

So it looks like my powerbook is sort of fine, but not really..... very frusted situation. What should I do now?

Tsai

 

[Ric]

Hi there,

do you have a Multimeter ? Do you have any way of checking the power adapter ?

The only time I have something similar is on an old PowerBook, that like yours the battery would not hold a charge...but the cable connecting the power adapted was frayed internally...so when the power adapter was plugged in it wasn't really charging the battery...

Do you know anyone who has the same type of charger ?

Or possibly pop the PowerBook into an Apple Store and see if they mind sticking in one of there adapters to see if it will boot ?

let us know how you get on !

regards

Ric