Thermal Paste Thermal Tape Question Logic Board

On my G4 1.5 gHz early model (BT 1.1), the CPU had thermal compound which was black and stiff. The system controller had what appears to be a thermal pad on the heat sink, and the GPU had a gray colored sticky putty-like compound, which I assume is silicone-based thermal paste. When I removed and replaced the logic board, I scraped off all the black stuff from the CPU die and copper heat sink, cleaned both with 91% isopropyl alcohol, and applied Arctic Silver 5 thermal paste to the CPU die and GPU surfaces. I am not sure if the GPU needs the thick silicone paste or not -- time will tell I suppose.

Look at this image for relative locations of the components. From left to right is the CPU, controller, and GPU.

It appears from iFixIt.com's guides that it's the same material for both? At least, the paste. They say when you remove the logic board, scrape off all of the paste from the old joint. Then, when replacing the logic board, to put in new paste compound on those two sections, but don't instruct you to use a special one on the left and another on the right. They just say "thermal paste."

[http://www.ifixit.com/Guide/64/images_large/46.jpg]

(This is from their main fix it guide for the 15-inch PowerBook 1.5/1.67GHz model).

Thanks -- I read the iFixIt guide, and also the guide over at powerbookmedic (which does not mention the thermal paste, unfortunately). Powerbookmedic.com has the orange static tape you need for taping things to the innards, which I could not find anywhere else. Their thermal paste did not identify the manufacturer nor type, so I bought the Arctic Silver 5 from my local Radio Shack.

The Kapton tape is available on eBay. So are the spudgers, Apple's "black sticks."

Thank you!!!

You helped me out in turn. I am endeavoring to restore my PowerBook to brand new condition (no scratches, no dings, nada) and that's the thing that's worrying me. The thermal paste issue. I never thought of it until I read your post.

Irony is that I'm helping you in the process of helping myself. And you've helped me out by pointing out that that paste is available at RadioShack. I will go buy that now.

(When I bought a bottom case on eBay, and then looked at iFixIt to see how to do it, I thought the thermal paste I already have would suffice. I have a tiny tube of it from a previous installation of a processor upgrade. Then after helping you with your posting, and then studying that picture, I realized that I may not have the right stuff and didn't want to touch a good logic board and the other innards just to have a scratch free bottom casing).

Message was edited by: Pismo 900

And I just also realized that we are talking to each other but the original poster is the one who needs the help. (I thought you were the original poster and I just looked. It's someone else).

Sorry for invading your space brettkramer!

Oh, the irony! Did you see this? =)

[http://www.ifixit.com/Apple-Parts/Arctic-Silver-Thermal-Paste/IF179-010]

Yes -- I did see that they had the AS5 -- I bought at RS because with shipping, I would have paid more than the $9.99 RS was charging. If you are near a Fry's, you can get it for $7.95 (assuming you want to stand in the lines!)...

I went to RadioShack yesterday afternoon, like I mentioned, and got the one you got too. Though I am near Fry's, it's the drive out there that I didn't want to do yesterday.

I'm guessing you're in the California/West Coast area, because of the Fry's thing?

I'm going to check CompUSA to see if they have it too. Before they close down.

OK -- an update -- The Arctic Silver 5 works fine for the CPU and GPU. However, the GPU needs a thicker layer of the thermal paste because the GPU does not make direct contact with the heat sink like the CPU does. I applied the AS-5 to the GPU according to the Arctic Silver directions (a layer about the thickness of a piece of paper). It worked fine for a month or so, until I ran a game that stressed the GPU. Then the screen went wonky. When I pulled the logic board, the GPU had the thin layer of AS-5 on it, but there was none on the heat sink, so I cleaned it up and reapplied it as a thicker layer. This time I checked to make sure it was in contact, and cleaned it and applied another thick layer. All is well now.

Message was edited by: Dana Leighton