
I bought a bunch of Green751 parts from
@DeltaDon, so I should be able to fully document these now.
Included three motherboards and two sets of case pieces with most internal parts. Two DSTN screens which both work, and a TFT one that’s cracked.
One of the three boards was in an assembled unit, and that one did work. Unfortunately, just my luck, after taking it apart to swap the case pieces, I’m now having problems.
One of the two other motherboards did also POST, but the third is missing the DC jack for…some reason.
All three boards had soldered VARTA batteries on them, same as the G753. The battery on the board with the missing DC Jack was intact, but the batteries on the two working boards had both begun to leak. Both broke vias that appear to go into the parallel port, so they may have trouble. I removed all three batteries.
So, the problem. During my testing, BOTH working boards started experiencing the same fault. They’d make it some way through post, then reset, and would freeze up randomly at the post screen. It would never reach the point where I could actually get into BIOS. The fact that it’s happening on both boards now is weird - makes me think it’s something else. I doubt it’s the display assembly, as otherwise I should still hear it post beep every time. The only two things I can think of are the following:
1. Even though the CMOS batteries were leaking, perhaps these boards need something connected through there or they get cranky? I honestly doubt it - usually if a board is picky about CMOS batteries it will not work right when it’s dead, not just when you remove it.
2. On one test, I I realized I had one sub-board connected incorrectly (had one set of connector pins misaligned so whatever was going through those pins made was going to the wrong place). According to the documentation that came with the laptop, this board down converts 3.3V to 2.9 for the CPU. Perhaps doing this fried the CPU? I don’t have another compatible one to test with at the moment. The issue did crop up around the time after I did this, but I feel like it would have immediately fried the chip if it did cause damage.
Now it’s just stopped posting at all - the CPU gets warm, speakers respond to the volume keys on the keyboard (small pop sound when I click them), but no post. I’m sure I’ll figure it out eventually, with more parts swaps and stuff.
I’ve also ruled out the 2.9V board and the main DC/DC module, swapped both with spares with no change. AC adapter is fine.