Guidance in troubleshooting

Semiconductor Integrated Circuits (ICs)
1

Hi,
I was wondering if anyone could advise if I have gone the right route for diagnosing my laptop (Acer Helios).
I have attached the schematic.
The laptop was not turning on and there was no signs of power.
I injected voltage at the power input and measured the motherboard under a thermal camera. PU4501 was getting hot. I gather that PU4501 is the converter creating the 3.3v and 5v power rail.
I removed PU4501 and noticed a short on the 100K resistor on pin 7.
I injected voltage at the resistor and measured heat coming from U3801 and U3802 which I believe are the USB controllers.
From there I measured a short on resistors C3812 and C3801. When injecting voltage there, the chipset got hot.
I therefore gathered that the chipset is kaput.
Am I right? What would your approach be?

Thanks in advance.
bios-fix.com_WistronGhibli_CFSrsc0328_18803 scheamtics (1).pdf (6.1 MB)

2

Devices this complex do not lend themselves easily to troubleshooting and repair; even at minimum wage, purchasing a replacement would likely be the more economical use of your time.

2 Likes
3

Thank you for your response
I would like advice on my troubleshooting methods.
If I wanted a new motherboard, I would have asked where I could get one…

4

Hello urad29,

Just a quick follow up note:

There are a few people who repair PCBs and post the information to YouTube. In my personal opinion they are like watching skilled surgeons. You may be interested in:

NorthridgeFix - YouTube

Actually, lets open this up to the community.

Where can we find PCB repair information? Do you have a favorite video personality?

Happy soldering,

APDahlen