Thanks, I'll read through it 
The G4's, as I said, is now written off because of the below reasons:
#1: Charred components in the IDE power section. (Black PCB and missing traces etc)
#2: While powered on, it started to make a chirp/hiss noise, two legs on the VREG went black, and smell of ozone
#3: Powered on to full blast fan, started to smell burnt after a while.
If I had gotten my hands on them before some inexperienced guy touched them, I am sure I could have gotten them back up and running, especially #1, as the initial problem was BGA soldering cracks on the graphics chip. A reflow would have fixed it.
Almost all the "how to fix it" documents and threads I have read is about adding shims. This is, at least in my opinion, a ghetto fix which does not solve the root cause. A heatgun reflow works and is more permanent (for the BGA) or just plain solder and flux (on the VREG). Applying too much pressure on the PCB can easily damage other solder connections due to the added stress it puts on the PCB. Just my 2 cents.
Now, the 12" mystery, I still don't get it. I tried to make it crash by pulling and inserting the power plug on it, and it stayed alive. The battery also works fine. The sys uptime is now over 14 hours and still counting.
The G4's, as I said, is now written off because of the below reasons:#1: Charred components in the IDE power section. (Black PCB and missing traces etc)
#2: While powered on, it started to make a chirp/hiss noise, two legs on the VREG went black, and smell of ozone
#3: Powered on to full blast fan, started to smell burnt after a while.
If I had gotten my hands on them before some inexperienced guy touched them, I am sure I could have gotten them back up and running, especially #1, as the initial problem was BGA soldering cracks on the graphics chip. A reflow would have fixed it.
Almost all the "how to fix it" documents and threads I have read is about adding shims. This is, at least in my opinion, a ghetto fix which does not solve the root cause. A heatgun reflow works and is more permanent (for the BGA) or just plain solder and flux (on the VREG). Applying too much pressure on the PCB can easily damage other solder connections due to the added stress it puts on the PCB. Just my 2 cents.
Now, the 12" mystery, I still don't get it. I tried to make it crash by pulling and inserting the power plug on it, and it stayed alive. The battery also works fine. The sys uptime is now over 14 hours and still counting.