Do I need to add thermal compound?

Thank you Mayer, however, I have already seen that guide and performed it successfully on quite a few other PowerBooks, but they didn't have the 128MB ATI graphics that this machine does, and they only had thermal compound on their processor, not the graphics card. The heat sink on this machine does have two copper plates, one under the processor and one under the graphics card. I suspect that I will need to apply paste to both areas, but as it isn't described as such in the iFixit guide, I wanted to make very sure before I make a mess of things. I thought, when I pulled the faulty logic board from this machine (which has a short circuit), that the short may have been caused by compound being on the graphics card too. Then I saw the eBay picture of the logic board I just bought, and noticed compound on that graphics card too! Thanks again! ;o)

I really don't remember seeing this problem before. Do you have the Apple part number on the logic board? Maybe I can help you do some research on this.

The Apple part number is 820-1940-A.

And here is the eBay item with photo showing graphics card in the top centre and processor top right, both with paste residue on:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?V...

I have this machine in my parts pile and saw the reason they missed it in the teardown, it's on the bottom side of the board. Mine has paste on it also. So I would replace it.

Thanks Mayer, your help is greatly appreciated. ;o)