How to build a T43 southbridge cooler

The T43 has a serious thermal design problem, where the area under the touchpad get very hot. This causes a problem with fan noise and a problem with hot surfaces.

The culprits are the Intel 82801FBM southbridge and the mini-PCI WiFi card, which generate significant heat and don't get adequate cooling. Moreover, these components are adjacent to the GPU, whose potentially high temperature affects the whole region of the planar board.

This page documents a successful hardware mod for thermally attaching the southbridge (and to a lesser extent the mini-PCI card) to the PCMCIA card cage. Since the PCMCIA cage is a major air intake and gets significant air flow, this effectively cools the southbridge to a comfortable temperature even under full system load.

ATTENTION!

This hack may damage your ThinkPad or you, and will surely void your warranty.

Phillips #1 screwdriver
Sharp knife
Thermal epoxy (e.g., Arctic Silver Thermal Adhesive)
A 4"x2" sheet of 0.0135"-thick copper plate (e.g., from OnlineMetals.com). You can probably get away with slightly a thicker plate, but much thicker will make the palm rest bulge against the LCD.
Heat-resistant electrical tape, or a thin sheet of some heat-resistant electrically-isolating material
Ruler
Heavy-duty scissors
Patience

Opening up

Disconnect power and batteries
Remove hard disks
Remove the keyboard
Remove the palm rest. Use the knife to carefully peel the screw covers; you'll need them back later.
Remove the mini-PCI card

You can now see the southbridge, which is the big black chip under the mini-PCI slot.

Making the copper heatpipe

Cut and bend the copper sheet as follows, using the scissors and ruler. Make the flat areas as straight as possible.

Cover all areas that may touch exposed electronics (see below) with heat-resistant electrical tape.

Fit the copper heatpipe in place under the mini-PCI slow and bend it so it sits snugly, as in the photos below. Push it all the way to the left against the mini-PCI slot (I have a small gap between the two, which was a mistake).

Try placing the palmrest back and make sure the heat pipe doesn't get in the way.

Gluing the heat pipe

Cover the southbridge with thermal epoxy. Be generous, since it needs to fill the gaps under the copper plate (which is not that flat by now). Do the same with the relevant area of the mini-PCI cage, being careful not to plane glue on or near the moving parts.