Chosen Solution
Hello, MacBook Pro non-unibody 15" Core 2 Duo 2.5Ghz Model A1260 - Early 2008 that doesn’t turn on. Logic Board 820-2249-A It has the nVIDEA 603 chip, the one that is considered more robust. Most of the problems with nVIDEA chips were the 602 model. Battery, PSU, RAM and Power button are working fine, those were already tested. SMC was already reset The PSU connector shows “Green Light” when connected, nothing happens when I press the Power Button.
I was able to force start the computer by doing something that was suggested in another thread, it’s an SMC Bypass power up: 1- Remove Battery and PSU connector 2- press Power Button for 10 seconds 3- while keep pressing power button insert PSU connector 4- then continue pressing for another 10 seconds 5- the Macbook will boot up normally, graphics, RAM, HD and OS work has supposed. Battery will not charge if you insert it after because the SMC was bypass, an the battey charging duty is controled by SMC Power button will work for Shutdown
So the MAC works and starts if the SMC is bypassed, probably or the SMC chip is bad, or any circuit around it, or it could any part of the circuit the SMC controls I have electronics knowledge, and SMT soldering skills and equipment. I would like to Repair my Logic Board and not replace it. Theres a lot of people having the same issue, but not a lot of info besides replacing the whole logic board Does anyone know what is causing this problem in Non Unibody Macbook Pros? Is there anyone around here that was able to fix their Logic Board? Thank you so much for your help
You should be able to find schematics and board views on line for that motherboard. Once you have them, Post the resistance to ground on PP3v42_G3H
