Gateway MX8739 - Dead

[Oklahoma Wolf]

Picked up this 17" laptop cheap off eBay as a project. I've done about all I can do on it, and have pretty much hit a wall. Thought I'd post here and see if anyone has any ideas.

Symptoms are - it's dead. No sign of power anywhere on the unit. Battery claims to have a charge via the built in gauge, but I doubt it works... it also gives me nothing to work with.

Power jack has been ruled out - I've been working with it using soldered in wires running to a compatible power brick.

Here's what I have for measurements so far:

PQ51 (an AO4914): pins 1-3 have 0.96V on them. It blips to 1.05V at regular intervals, so I think it's trying to do something but failing. Pin 4 has steady 1.14V. Pin 5 and 6 both have 19V from the adapter. Pin 7 has 1.5V, pin 8 has 0V.

PQ50 (AO4413): pins 1-4 have 0.35V jumping to 0.60 at intervals. Pins 5-8 have 19V.

PQ49 is the interesting one, also an AO4413. Pins 1-4 get 0.95V from coil PL10. Pins 5-7 have 0.35V from PQ50. Pin 8 is the odd one... it jumps from 0.1V to as much as 8V. Not sure where this goes.

Fuse F1 on the other side of the PCB tests good. No power on either side of it.

Anyone have any ideas from here?

[Th3_uN1Qu3]

Re: Gateway MX8739 - Dead

Is it just me or are those liquid spillage traces? If so, nothing can be done about it, i had a Samsung that had water spilled into it and the most i got out of it was charging.

But first, split it into blocks, it's easier. Check power to the CPU, chipset area, GPU if there is one, and so on. If it doesn't get power to the CPU or chipset it's pretty obvious why it doesn't work. You do power supply reviews so you do have an oscilloscope - check all PWM controllers on the board and make sure they're oscillating. If all go, check gate drive to all power MOSFETs. And so on.

[Oklahoma Wolf]

Re: Gateway MX8739 - Dead

Nope - that's glue residue. There apparently used to be a shield on that part of the board - missing on mine, because someone's already been monkeying with it.

Can't find any liquid spill traces on the board. They may have been cleaned off by whomever got in here last, in which case the board is probably toast.

PQ51 pins 1-3 now have 4V on them. PQ49 pin 8 is still jumping around.

[Oklahoma Wolf]

Re: Gateway MX8739 - Dead

Chipset area is getting about a quarter of a volt. No power to GPU area.

[Oklahoma Wolf]

Re: Gateway MX8739 - Dead

Yeah, this thing needs a new motherboard. Not sure I'm going to be able to do board level repairs on this one. She's a parts machine now.