HP Tx1000 repairs, part III – BBQ GPU

On removal of the heat sink and fan assembly, the next part of the repairs was a bit of a cleanup. For some bizarre reason, HP had sprayed the heatsink fins with a black gucky paste which has attracted all manner of dust. A bit of compressed air had cleared the dust but I read that it was best to remove the black stuff too.

Sexy black but not sure how this helps to extract heat.

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After about half an hour scrubbing away with an old toothbrush and plenty of Acetone/Nail polish remover, the gunk was finally coming off.

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Another half hour of scrubbing and all traces of the black stuff was gone. Next up was to clean away traces of the old thermal compound residue from the heatsink and CPU using some Akasa cleaning fluid I’d brought the other day from Maplins. This stuff is fantastic, a few drops and a wipe with a cloth was all that was needed.

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Before.

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Afterwards

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With the cleanup, out of the way it was time to move to create a makeshift heat shield to protect the motherboard while is was cooking:-)

Following the instructions online, I traced the outline of the motherboard on to a piece of cardboard and measured out where the GPU sits in relation to my cardboard template.  I them cut out a square hole in the cardboard so that all of the motherboard was covered by cardboard apart from the GPU sticking through the hole (hope that makes sense!).

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Another use for my PDA..a portable instruction manual!

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The final part to create the cardboard heat shield was to completely cover it with Tin Foil and create a little whole where the underside of motherboard were the GPU is located is  exposed.

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Time to BBQ the GPU using a desk lamp. The idea here is to heat the GPU pins to a temperature that softens the solder allowing the chip so it can be pressed back on to the motherboard. My instructions advised using something like a 100-200w bulb suspended over the GPU for about 1-2 mins but all I had initially was a 60w bulb.

After leaving it for about 5 minutes the motherboard wasn’t even warm so, as an alternative, I used my soldering iron (which was a blow torch feature) to heat things up a little. I didn’t want to cook it so I only applied heat for a few seconds, checking to ensure I wasn’t applying to much. When it was quite warm, I removed the makeshift heat shield and using a paper towel, applied pressure to re-seat the GPU back on to the motherboard. I didn’t hear a click or anything so at this stage I could only guess that things had gone well.

Turning up the heat

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Tomorrow, modifying the heatshield and testing.

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