Reassembled XOs fail heat spreader test

[Sridhar Dhanapalan]

We are currently engaged in changing the motherboards in over a
hundred XO-1.5s. In many cases, the XOs are failing the heat spreader
test afterwards.

However, we can get the test to pass if we press down on the lid,
behind the screen. This suggests to me that the heat spreader is not
in proper contact with the chips.

Without the lid plastic affixed (heat spreader exposed), we can see
that the spreader is not touching the chips properly. We have tried
bending the metal slightly near the screw points, but the contact
doesn't last.

Is there any way that we can deal with this better? We are changing
the motherboards in these XOs because they have succumbed to
overheating. I want to avoid that from happening again.

Thanks,
Sridhar


Sridhar Dhanapalan
Engineering Manager
One Laptop per Child Australia
M: +61 425 239 701
E: sridhar at laptop.org.au
A: G.P.O. Box 731
     Sydney, NSW 2001
W: www.laptop.org.au