68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.

Mid-05 12" iBook G4/1.33 CPU PLL Resistors?

Posted by: John8520 on 2021-10-19 11:27:01

I have a few of these iBook G4s, and I'd like to take a swing at overclocking them a smidge (or underclocking for better battery life, perhaps?)

I found this forum post from 2010 regarding an 800Mhz iBook G4 overclock, but this model does not have PLL resistors in the same place. Below is a photo of the under-CPU region of one of the boards in question, where I would expect to find such resistors. I have yet to find a schematic for this board, but that would quickly answer the question.

Posted by: Ncc74656 on 2024-06-23 19:49:58

did you figure this out? i dont see anything in that photo that looks like a resistor bank for the VRM's. might be on the other side of the board? i have a 1.42 ibook and i did find that forum you are refrencing but all the photos are down. you dont have htem do you?

Posted by: alectrona6400 on 2024-06-23 21:09:58

I might actually have spotted a difference between the two boards but I don't really have access to a spare board anymore... I do like the idea of getting the FSB clocked to 167MHz though, as the 2005 iBooks only run at 133MHz for the 12" board and 142MHz for the 14".

Posted by: Ncc74656 on 2024-06-23 21:32:46

i have hte 14. ive clocked the G4's up. id have to dig into this to try and find hte right resistors.

Posted by: John8520 on 2024-06-26 06:48:07

did you figure this out? i dont see anything in that photo that looks like a resistor bank for the VRM's. might be on the other side of the board? i have a 1.42 ibook and i did find that forum you are refrencing but all the photos are down. you dont have htem do you?

Nope, never got around to figuring it out. The archive.org link for that forum post includes the photos:

Overclocking my iBook G4 - Apple Computers and Hardware

Overclocking my iBook G4 - posted in Apple Computers and Hardware: I have an old iBook G4 sitting around that I would not mind messing up if this goes wrong (cheap enough to replace the logic board if I do). I only found one guide that shows how to change some resistors on the bottom of the...

web.archive.org

Might be worth reaching out to dosdude1 - he may have schematics for later iBook G4s.

Posted by: Ncc74656 on 2024-06-26 19:47:43

kool. ill dig into that when i tear it open to repaste it