In article .net,
says...

snippety

I've run the mboard out of the case with just power, and pressed,
squeezed,etc. without any hint of what I'm looking for. I've examined it with
a glass looking for cracked board and/or traces, separating solder joints,
the obvious. It does still fail out of the case, so this isn't a
short-to-case issue.

Any ideas what else this might be? Do ASICS and other ICs fail (internally)
in this mode?

Remember that any modern computer motherboard is going to have a
bare minimum of four layers. Most have six, and I've even heard of a few
that have eight or ten.

It sounds to me like the board you're working with may have
developed a hairline crack somewhere. Short of inspection with high-end
ultrasonic or X-ray equipment (which probably costs more than you, me,
and my wife make together in a year), I really doubt you're going to
find the problem, much less be able to fix it.

Time for a replacement motherboard.

Happy hunting.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
(Known to some as Bruce Lane, ARS KC7GR,
kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com
"If Salvador Dali had owned a computer, would it have been equipped
with surreal ports?"

"DaveC" wrote in message
news.net...
Mac PowerBook G4 won't boot (but will give the boot "bong"). If I press on
the case below the motherboard, it boots and, if pressure is maintained,
functions normally.

If pressure is released, video will scramble, and -- sometimes -- system
will
freeze.

I've run the mboard out of the case with just power, and pressed,
squeezed,etc. without any hint of what I'm looking for. I've examined it
with
a glass looking for cracked board and/or traces, separating solder joints,
the obvious. It does still fail out of the case, so this isn't a
short-to-case issue.

Any ideas what else this might be? Do ASICS and other ICs fail
(internally)
in this mode?



It's gotta be a trace, solder joint, or via. Try resoldering anything in the
area, if that doesn't work and it's otherwise garbage, you could try heating
up that area of the board with a heat gun until it's hot enough to melt
solder then let it cool off.

On Thu, 26 May 2005 14:29:27 -0700, DaveC wrote:

Mac PowerBook G4 won't boot (but will give the boot "bong"). If I press on
the case below the motherboard, it boots and, if pressure is maintained,
functions normally.

If pressure is released, video will scramble, and -- sometimes -- system will
freeze.

I've run the mboard out of the case with just power, and pressed,
squeezed,etc. without any hint of what I'm looking for. I've examined it with
a glass looking for cracked board and/or traces, separating solder joints,
the obvious. It does still fail out of the case, so this isn't a
short-to-case issue.

Any ideas what else this might be? Do ASICS and other ICs fail (internally)
in this mode?

Thanks,


It's probably a bad solder connection, but as others have said, it
could be a crack in the board. I've seen a number of laptops with bad
soldering on the DIMM sockets. Try resoldering everything that's easy
to resolder with the equipment you have. On a board like that, there
won't be much that's easy to resolder.

If the problem is on a BGA IC, you're out of luck. I guess you could
try putting the whole board in an oven hot enough to melt all the
solder. It sounds crazy, but that's how it was originally soldered at
the factory.
Andy Cuffe

-- Use this address until 12/31/2005

-- Use this address after 12/31/2005

Andy Cuffe writes:

If the problem is on a BGA IC, you're out of luck. I guess you could
try putting the whole board in an oven hot enough to melt all the
solder. It sounds crazy, but that's how it was originally soldered at
the factory.

But they ususally do this before the plastic parts are attached.

Try it at home and you may find slag where you once had DIMM sockets.

-- David

"DaveC" bravely wrote to "All" (30 May 05 12:33:01)
--- on the heady topic of " Laptop motherboard fixes with pressure"

Da From: DaveC
Da Xref: aeinews comp.sys.mac.hardware.misc:9529
Da sci.electronics.repair:49238
Da On Sun, 29 May 2005 18:14:33 -0700, quietguy wrote
Da (in article
Da ): ...
Da as a suggestion perahps you could try the Mac groups etc to see if you
can
find someone with a similar unit, but crook or broken screen - might be a
cheap way to solve the problem.

Da That's the backup solution. I've got nothing to lose by trying the
Da heat solution first.

Another idea would be to talk to a Mac technician - he may know any common
troublespots on your model board

Da Already have, several. They all say "replace the motherboard". Nothing
Da against them; they've learned the modular-replacement method. I'm
Da looking a little closer than that.


Dave,

They are not too far off the mark actually because a modern pc
motherboard is a rather sophisticated piece of technology. To be fair,
I'm assuming you have little repair experience and even less equipment
than is available in a well equiped kitchen. Put it this way, it is as
if you were to attempt brain surgery with stone knives and suture the
wound using bone needles. Please, forgive me if my assumption is wrong.

A*s*i*m*o*v

.... Back when I was a boy, we carved our own ICs out of wood.