Thinkpad Z61t FIXED, caused by weird plastic PIC

[GnatGoSplat]

I have a Thinkpad Z61t with a T5600 Core 2 Duo 1.83GHz processor that I picked up from eBay. It had a strange problem where it would just randomly shut off under heavy CPU load for no reason. It's still under warranty, but I'm a pretty technical guy so I didn't think it'd hurt to take a peek under the hood.

I pulled the CPU heatsink, and here's what I found.


It's a weird piece of plastic with adhesive tape on it attached to the heatsink and was sandwiched between the CPU and heatsink. It had grease on both sides. It seems to be the exact same type of plastic used for blister packs. I may not be an expert, but that didn't seem like any kind of silpad I'd ever seen, and my knowledge of plastic is it's an insulator. It looked to me like the kind of thing that would be attached to a brand new heatsink to protect the pre-applied grease.

To confirm it's not some kind of special heat-conductive substance, I pulled the heatsink off my other Z61t which works perfectly, and it had no such plastic.

So I took that plastic thing off and reapplied grease to the bare CPU, reinstalled heatsink, and now it's been happily running HOT CPU Tester for some time now where previously it would shut off after about 10-seconds. Upon closer examination of that piece of plastic, it seems definitely like blister-pack plastic. It's even heat-warped. I'm quite positive it was just a protector for factory-applied grease. Wow, I wonder how somebody could miss that! I bet the seller unloaded the Thinkpad on eBay because they never got it working right.

[SMA]

Thanks for posting your finding.
Who knows - there can be hundreds of similar machines out there, all having the same problem.
Job well done.