RE: OT: HW-issue, PowerBook G4 Ti does not power on

>   PROBLEM:
>   my dear old PB G4 Titanium (500MHz, no Gbit, no DVI -

> the real old one) does not power on any more: whether I

> leave the battery in place or not,

Allen, Michael,

  thankyou for your information.

  I was not able to pull "ifixit.com" off google,
so I'm
glad I've been pointed to this: I've found and read the 
related article.

  Albeit I know where the PMU reset button is, I did not 
know that it does a "sane discharge": I merely
expected it 
to be sort of a 'logic' reset of the PMU and now I better 
understand -and agree upon- keeping it pressed for a long
time. I'll try harder on this in my spare time.

> >   what voltage at which pins are expected?
> Something between 12v and 16v IIRC, on the two inner
rings 
> of the central pin - the tip is unconnected or ground.

  I love to know this.  

  Is the DC voltage unregulated? 
  must it be precise within certain limits?

  I hope to be able to perform trials with my lab 
power supply, therefore also my next question:

  Is the outer "shell" also a ground connection?
(or does it only serve as a protection against shorts when
the DC cable is danging around?)

best whishes
Stephan

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Hello,

On Nov 13, 2007, at 04:27, Schwerzmann, Stephan wrote:

>>   PROBLEM:
>>   my dear old PB G4 Titanium (500MHz, no Gbit, no
DVI -
>> the real old one) does not power on any more:
whether I
>> leave the battery in place or not,
>
> Allen, Michael,
>
>   thankyou for your information.
>
>   I was not able to pull "ifixit.com" off
google, so I'm
> glad I've been pointed to this: I've found and read
the
> related article.
>
>   Albeit I know where the PMU reset button is, I did
not
> know that it does a "sane discharge": I
merely expected it
> to be sort of a 'logic' reset of the PMU and now I
better
> understand -and agree upon- keeping it pressed for a
long
> time. I'll try harder on this in my spare time.

On my PB3400c it took more than a minute. Just holding it
for a  
couple seconds won't do a thing.

>>>   what voltage at which pins are expected?
>> Something between 12v and 16v IIRC, on the two
inner rings
>> of the central pin - the tip is unconnected or
ground.
>
>   I love to know this.  
>
>   Is the DC voltage unregulated?

Good question.

>   must it be precise within certain limits?

I think so - should be roughly in the same region as
whatever the  
battery supplies. A few volt more or less shouldn't make a
difference  
- - the laptop has to convert it to 12v, 5v, whatever the
CPU's core  
voltage is and so on anyway.

>   I hope to be able to perform trials with my lab
> power supply, therefore also my next question:
>
>   Is the outer "shell" also a ground
connection?

I think it's connected to ground but I'm not 100% sure. The
connector  
is designed to make it almost impossible to short-circuit it
by  
accident.

> (or does it only serve as a protection against shorts
when
> the DC cable is danging around?)

Bit of both I think.

have fun
Michael
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