On Jul 27, 9:19 am, Maccountant <[email protected]> wrote:

> Has anyone done this before? I purchased a Sonnet G4 1.8gz MDX for my
> G4 single 1.25 MDD. It works fine but generates too much heat, even
> with the built-in fan. I want to remove the heatsink and replace it
> with an Apple copper one from a 1.45 G4 that I have but the Sonnet is
> screwed in in a proprietary way. I contacted Sonnet but the guy just
> said they attached it in such a way so customers won’t remove it. Big
> help. Has anyone done such a thing and can tell me what kind of tool I
> need?

i second the suggestion from pete.  just add another fan to the
heatsink.  you can get them at radioshack fairly cheap, or online.
but you will also want to have a way to power it, so you'll need MOLEX
plug adapter or a splitter.  if there are unused MOLEX plugs in your
computer (eg, for unused HD bays), an adapter will allow the leads
from the fan to connect to the MOLEX to get 12v for the fan.  if all
your MOLEX connectors are in use, the there are "splitter" type
adapters that will allow you to keep all your devices powered and tap
into one of them to connect the power leads to the fan.

as for removing the heatsink and replacing it, geke is correct that
there needs to be thermal paste, but i caution you about doing that,
especially about applying thermal paste.  virtually everyone gets this
wrong and uses WAY TOO MUCH paste.  it is a silicone compound, and
like all covalently bonded compounds, it is NOT a good thermal
conductor.  NOTHING is as effective as direct contact between the chip
and the heatsink.  the function of the paste is to fill in microscopic
gaps that are present when any two "flat" surfaces are pressed
together.  invariably, everyone applies too much paste and it ends up
preventing direct contact between the chip surface and the heatsink.
if the proper amount of thermal paste is used, it will be almost
invisible over most of the surface of the chip.  i have seen apple
computers shipped from the factory with egregiously excessive amounts
of thermal paste, particularly the G4 PB's, and they were notorious
for processor failure for exactly that reason.

so rather than trying to shoehorn the copper Apple heatsink onto the
Sonnet processor, you might want to remove the Sonnet heatsink just to
see if someone has already gooped it up with an excessive amount of
thermal paste, and if so, remove the excess.  however, DO NOT use
acetone to clean the CPU chip.  that's just plain crazy.  acetone is a
powerful solvent, and while it will not attack the plastic of the CPU
chip itself, it could damage any adjacent CB components with which it
comes into contact.  wipe the heatsink and CPU chip thoroughly with a
clean soft cotton cloth or a cotton Q-tip moistened with a little
isopropyl rubbing alcohol.  apply fresh (NON-METALLIC) thermal paste
judiciously and SPARINGLY then press the heatsink and CPU together
firmly.  if any paste squeezes out, you've used too much.  wipe it
from the edges and press them together firmly again.  when you pull
them apart, the surface of the chip and the heatsink that are in
contact should appear virtually "clean," ie, barely a "haze" of
thermal paste in a few spots only.  THAT is the PROPER amount of
thermal paste.  if yours has too much paste on it, removing the excess
will make it run MUCH cooler.

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