Powerbook 540c won't startup

[Iesca]

Hello all,

I had turned on my Powerbook 540c yesterday and it worked fine (although I forgot to turn on the external CD Drive so it wouldn't boot initially, derp). After using it for a bit, I shut it down as normal, but later in the day (and today) it didn't turn on; it remains completely silent.

Am I correct in guessing that the power brick finally bit it, or could it be something else? I have heard of recapping the Blackbird's power supply, though it requires cracking open the enclosure...

Thank you!

 

[Johnnya101]

You could try measuring the output voltage of the brick, however that wont tell you if its dipping under load. They usually all need to be recapped at this point. 

Edit: Also, Im not sure on the later Powerbooks, but on the 100 series, if theres a battery short it will cause issues. You could try removing the battery?

 

[Iesca]

Also, Im not sure on the later Powerbooks, but on the 100 series, if theres a battery short it will cause issues. You could try removing the battery?

No worries on the battery pack, it's been removed for some time. I did fabricate a new PRAM battery and install some time ago using keyfob cells, but that doesn't seem to work regardless...

 

[Paralel]

Zap the Power management chip. What you're describing can be a corruption in the power management system.

I forget the exact combo, but I know its documented.

When BlackBird power adapters die there is usually a loud pop, and/or, a flash of light (meaning a spark inside the adapter), and/or magic smoke. I've never seen one die quietly, and I've seen more than a few go over the years. If you didn't see any of those 3 things, it's unlikely your AC adapter is dead.

 

[Iesca]

From this list I tried out the given sequence, but to no avail. Sadly, I do recall hearing a click or mild popping at one point unplugging/plugging in the power brick, but I had assumed (or hoped) it was the same sort of crackling noise you sometimes get when plugging in a more modern Macbook power supply into the power outlet.

Edit: I tried both the standard Power Management Reset (Cmd-Ctrl-Shift-Power) and the PB500 specific one (Cmd-Opt-Ctrl-Power), both to no avail. Should it chime at some point? I'm not sure what is supposed to happen.

 

[Paralel]

Yeah, it should boot after that.

Sounds like you AC adapter died. There is no pop with these AC adapters under normal working conditions

 

[Iesca]

Dang.

Anyone have a cap list handy?

 

[perez6991]

I’d be skeptical on suggesting the ac adapter is dead. Try squeezing the outer metal contact that surrounds the 4 pins, it gets loose over time. My 520c was working completely fine and I had the same issue OP has. Couldn’t hurt to try.

 

[Iesca]

Would it be obviously loose? The metal outer ring on my adaptor seems pretty rigid. (Unlike, say, the one on the iBook G4...)

 

[Paralel]

Would it be obviously loose? The metal outer ring on my adaptor seems pretty rigid. (Unlike, say, the one on the iBook G4...)

Yes. If the interface is damaged, it should be obvious. It is far more rare than a dead power brick these days. Actually. I'd say dead powerbricks is the norm, rather than a functional one these days. Out of 5 that I have plugged in, 1 mostly works, but will cut out if it gets too warm.

 

[Iesca]

Thanks for the clarification! Gonna hafta dremel that thing open then to know for sure...

 

[Paralel]

Another method that has worked well, which is kinda bizarre, is to put a golf pencil (for some reason it has to be a golf pencil, regular size pencil does not work as well) on either side, in a bench vice, and just keep twisting the vice tighter until it opens. For some reason, way the the pencils apply pressure, it will always fracture right along that indentation where the two pieces join and pops right open. It's the damndest thing, but people have proven it works more than a few times here. There should still be pics that show how.

 

[Iesca]

How interesting! I'll have to keep in mind.

However, between some earlier prying and gentle hammering on a box knife I was able to get the case open.

And I think we have found the problem... (see photo)

There is a shield underneath, any tips for removing that, or just have to unsolder it at the solder point?

 

[CC_333]

I opened one by prying a bit and cutting along the seam with a box cutter. I think it cracked in a spot or two, but it was actually rather easy compared to, say, a MagSafe brick!

Maybe it was beginner's luck?

c

 

[Iesca]

It seems we hit upon the same solution!

 

[Iesca]

For those in need, I made a diagram!

 

[Paralel]

Thank you. The info you have provided has been quite helpful for those of us who eventually will have to recap their power supplies as well. Damn things.

 

[Iesca]

Damn things.

Damn straight...

 

[CC_333]

I have at least one, possibly more, PB500 AC adapters that need to be recapped. This will help me to do that!

Now all I need are the capacitors....

c