Powerbook G4 mod

Discussion in 'PowerPC Macs' started by reddrag0n, Nov 25, 2011.

  1. reddrag0n macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #1
    Recently acquired a PB G4 15" 5,6 and i noticed that it runs hot. As part of the mods that i want to do to this laptop, i was wondering about a cooling mod.

    Now i already redid the thermal paste and i need to get new thermal pads, would it help if i made some slits just under the fans so that fresh air can be drawn in through the bottom and then out the back?
    Or would that just screw up the air dynamics?

    I am going by what i see on regular PC laptops, that they have slits and mesh to prevent dust from coming in, so can this same type of concept be done to a Mac laptop?
     
  2. adcx64 macrumors 65816

    adcx64

    Joined:
    Nov 17, 2008
    Location:
    Philadelphia
    #2
    Hmmm,
    I believe apple sets up the cooling systems in a certain way to maximize cooling, but I don't see how adding more fresh air could mess things up. I say go for it as I cannot see why more air circulation could hurt. Just make sure you put a mesh in the way so dust does not get sucked in.

    Good luck! :)

    btw, pretty cool mods on your site in your sig!
     
  3. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #3
    Well, from what i can see, when the PB is fully ripped apart, there is no way that fresh air can be drawn in from the lower air vents. It all looks like a closed system. This is why i was thinking of adding the fresh air vents.

    This is the picture i am referring to.

    And thank you about the mods, i also did one to the apple logo on this laptop.
     
  4. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #4
    Well performed the cooling mod, made G5 like holes underneath the fans to maximize cooling and i found something out!!!

    The Powerbook overheated and caused video glitches. So grabbed the tape, covered the holes i made and now it cools properly again.
    The graphics chip for some odd reason ran up to 60+ degrees Celsius and caused vertical lines on the screen and locked up. Shut down the PB, taped up the holes and let her sit for 30 min. Afterwards she started up normally again and the video issue was solved with it's own cooling method.

    So, drilling holes under the PB for maximum cooling is a bad idea. Leave the bottom plate in one piece.
     
  5. burnout8488 macrumors 6502a

    Joined:
    May 8, 2011
    Location:
    Endwell, NY
    #5
    From what I've discovered it seems the GPU doesn't make contact with the heatsink unless there is a thick layer of thermal paste between it and the heatsink. It is not like the CPU where the die actually makes contact with the heatsink. That may be part of your problem as well.
     
  6. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
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    #6
    Yeah, i noticed that when i first too it apart. Thermal paste from h**l. After, i put in thermal pads that were thick enough for both the VGA and the chip next to it. So they have proper contact, but i think it's because the airflow was disrupted and caused the system to freak.
     
  7. burnout8488 macrumors 6502a

    Joined:
    May 8, 2011
    Location:
    Endwell, NY
    #7
    Oh, I see! You put a thermal pad in place of the insane amount of GPU paste. That's probably better than what it was from the factory.
     
  8. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #8
    Yeah, what i did was take the pads from the bottom heatsink pads from a pair of old G5 1.8 processors, put them on top of each other and went to work approximating the height of each chip. Since the main NB/SB chip required only 2 pads high to touch the heatsink and the vga chips (all 5 of them) needed 4 pads to touch the heatsink
    So i cut a square big enough to make the large ship and i cut the rest to make 5 - 4 pad high stacks and put them on the vga chips. put everything back together and watched the machine come to life with a bit cooler chips.

    Yes, Apple did a horrible job gobbing the thermal paste on the chips to make due for the cooling on these notebooks. Hence why i hate the idea of these designed in California, but made in podunk Korea. They have no idea how to make proper thermally controlled units.
     
  9. goMac macrumors 603

    Joined:
    Apr 15, 2004
    #9
    This is because you've changed the airflow direction. You can't randomly drill holes in a case and expect that will make things cooler. It's causing the warm air to pool in the laptop.

    Unfortunately, the G4 was an insanely hot chip. There isn't much you can do. The only real way around is increasing the air volume which means putting it into a larger case.
     
  10. reddrag0n thread starter macrumors 6502

    reddrag0n

    Joined:
    Oct 1, 2007
    Location:
    Canada
    #10
    I didn't put random holes in the bottom case, it was a set of holes right underneath each fan for fresh air intake. Careful measurement was done, and the holes drilled with precision. Since every other PC laptop has the same design, i tried to replicate the same thing on the powerbook.
     
  11. iModFrenzy macrumors 6502a

    iModFrenzy

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    Lead The Way!
    #11
    I know this is an old thread but I've seen this done to MBPs too, which confuses me on how it overheated...
     
  12. RhianB macrumors 6502

    RhianB

    Joined:
    Sep 3, 2016
    Location:
    Albuquerque, NM USA
    #12
    Old thread aside, I think it is more likely that a previous owner before the OP went nuts with the paste. IME apple is thermal-pad happy if anything. After watching a few of the YT apple keynote addresses where the apple design folks talk about the evolution of their cooling/case design up to the unibody, I would not assume that more air intake is a better thing. I'd focus on cleaning out inevitable dust build up, replace any gooey melted thermal pads, and leave it at that.

    With that being said, I did read where folks installed an additional (small) exhaust fan on the 06 20&24" imac cases around the upper right hand corner which improved things in that singular instance. Still, they were increasing exiting air flow across components, not air intake with extra holes. Who knows, I'm no engineer, but it does make sense to me that if you increase your air intake (assuming your fans are at max speed) that you will also need to increase the amount of exhaust pull by adding another fan or air moves slower across your components as you now have say ... 4 air entry points vs 1 or 2 - easier to do in a desktop design - not at all so easy in a laptop design.
     

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