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

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