[ltp] Thermal pads and GPU cooling

[Adrian Filip]

I'm in the same situation as you, but I haven't ordered yet the new thermal
device and fan for my laptop.
The laptop's type is 8744-C9U and the FRU for thermal device and fan is 41W=
6409.
At a quick glance on the net I discovered that the replacement is expensive=
,
the two parts are coming together and I couldn't find only the fan. If
somebody knows if it's possible to change only the fan please let me know.

If the bending of the heatsink fix the fan issue please report back.

Thanks.

P.S. I also read this: Download and install the May 2011 Bios Update Utilit=
y
2.27 and May 2011 Power Manager 1.99g.  Lenovo fixed the temperature fan bu=
g.
Source:
http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/ThinkPad-T60p-f=
an-replacement/td-p/27827/page/2

On Mon, May 30, 2011 at 4:51 PM, Richard Neill <rn214@richardneill.org> wro=
te:
> Dear All,
>
> I think I may have got to the root of why my T60p has the fan on all the
> time, even when idle.
>
> 1. I've already replaced the fansink unit with a new one (fan bearings we=
re
> failing), having cleaned the thermal bonding surfaces. The new fansink un=
it
> is identical to the old one:
> =A0- it has a very thin layer of thermal paste between the CPU and the co=
pper
> plate (with pressure applied by screws)
> =A0- it uses a 1mm thick "thermal pad" onto the northbridge, (with slight
> pressure)
> =A0- it uses a 2mm thick thermal pad onto the GPU, (with slight pressure)=
,
> misused (imho) for gap-filling.
>
> 2. The result is that, when idling, the CPU (sensor 0) sits at 44 degrees=
,
> but the GPU (sensor 3) sits at 78 degrees, requiring the fan.
>
> 3. Some specs for this type of thermal pad are here:
> =A0http://www.farnell.com/datasheets/530848.pdf
> Thermal conductivity is about 5 W/m/K.
>
> The equation for heat-flow is:
> =A0power_flow =A0=3D =A0thermal_conductivity * (area / thickness) =A0* de=
lta_T
>
> This means that with a pad 1cm x 1cm x 2mm, and a GPU that idles at 5W, t=
he
> temperature drop across the thermal pad is 20 degrees! So the heatsink ru=
ns
> cold, while the GPU runs hot. I knew these things were bad, but that's
> terrible!
>
> I shall bend the heatsink to be the right shape, and then use thermal
> paste...will report back.
>
> Hope that's of interest.
>
> Richard
>
> P.S. =A0Normal thermal pads, as supplied on stock intel cpu coolers are d=
ecent
> enough - they are less messy than thermal grease, but work almost as well=
.
> However, they are usually about 0.1mm thick, not 2mm.
>
> --
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>