Replacing fan assembly on T43p

[davidski]

I have a T43p (2668-CMU) which has developed a horrible grinding noise from the fan under certain speeds (most commonly when running off of battery). After a rather torturous series of conversations with Lenovo support, I have a new fan assembly (FRU 26R9074) for self-installation. Ordinarily, this wouldn't bother me but I've run into a hitch that doesn't seem covered in the FRU service manual.

According to pp 103-104 of the June 2005 manual, once the screws are out, inserting a flat head screwdriver between the CPU and the fan assembly should allow the fan to pop off. Trying this myself, I'm getting a lot of resistance from the northbridge connection. It seems like the fan assembly is attached via some sort of thermal adhesive to the northbridge chipset. Is this common with the T43p's and, more importantly, how may I safely remove it so that I can install the new fan kit?

Thanks for the help!

[EOMtp]

There is no adhesive. The heat sink/fan assembly will lift off after you remove the screws. The only resistance is the "suction" effect which results from the good contact that the thermal compound (CPU) and thermal pad (GPU) provide.

[davidski]

Darn. That's actually disappointing to learn as it means I may need to push even harder. It felt like I was already putting quite a bit of pressure on the fan, to the point where the fan housing was beginning to bend. All the resistance was coming from the northbridge side. All three screws were definitely removed.

Any suggested methods for safely releasing the suction from the chipset so as to allow a removal without quite so much force? I'm pretty comfortable working with desktop components, but am inexperienced with the smaller scale of these laptops. Yanking this hard on any component, especially the CPU, makes me very nervous.

Thanks again.

[EOMtp]

There should be only two places where the heat sink may be "stuck" on components:
(1) on the GPU (the ATI chip), which is the protruding extension of the heat sink toward the lower center of the notebook, which has a thermal pad about 1" square, and
(2) on the CPU, where there is a 1/2" rectangular area that contacts the top of the processor.

Start by lifting the GPU part of the heat sink from its right side (the edge farthest from the fan vent), and keep lifting/rotating the assembly so that you can pull the exhaust manifold out of the lip created by the keyboard bezel, i.e., lift from the right side to about 20 degrees off horizontal, and pull to the right to remove.

You can use a sharp long very thin razor blade (one of those pocket pen retractable box cutters) to "break the seal" where needed. Do NOT use a screwdriver at all, and not the way shown in the document you mentioned. A razor blade will break with less torque than it takes to damage components; a screwdriver will not break! However, you should not need to apply any more than minimal torque.

Do not forget to disconnect the fan cable from the motherboard.
Good luck!

[agarza]

You say there's resistance in the northbridge chip, then I guess that confirms a variation of fan T43p has (the fan assembly goes to the NB chip in order to keep the heat down). Anyways, you should always lift the fan perpendicular to your motherboard, there should not be a lot of resistance, but you may go with the razor idea (although I panic if I ever could scratch the CPU mirror-finished core.

[EOMtp]

I forgot to mention that for this problem dental floss works even better than a razor.