Electronics > Beginners
Learning motherboard repair
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SolderOcelot:
Why this topic?
I've been wanting to learn computer motherboard repair for over 1.5 years. You would think there is plenty of resources out there but I strongly disagree. I've learned so much by my self on the internet (cooking, coding how to do a double windsor tie knot) but when it comes to computer motherboard repairs, I find that Louis Rossman, iPad rehab and even Sorin jump right in the middle and don't really consider beginners.

What's the device?
It's an old Lenovo laptop with a faulty motherboard. I can replace the motherboard for $ 38 but that's not the point of this project.
Model: Lenovo x220
Motherboard part number: 48.4kh17.021

Facts

* Symptoms: No power, no boot, no charging led
* Charger has been checked and replaced
* DC jack has been replaced
* DC jack connector on motherboard has been measured with multimeter
* In the past (while the mobo was still faulty) I have been able to get the motherboard to power and boot laying bare like this (with just keyboard and hdmi cable attached)
* CPU gets warm when motherboard is connected to DC jack for over 5 to 10 minutes
Question

* What's the sensible next component to check without using schematics and why?
* Shouldn't I have 20.5V on the black to ground point where I have 0V now?
Please bear in mind I'm an electronics beginner and so extra info on your comment is appreciated.
tszaboo:
Check all the fuses. That PCB looks damaged, maybe try to clean it and see if it is in one piece or charred and dead.
SolderOcelot:

--- Quote from: NANDBlog on November 13, 2019, 03:20:10 pm ---Check all the fuses. That PCB looks damaged, maybe try to clean it and see if it is in one piece or charred and dead.

--- End quote ---
Thank you. I've cleaned it with IPA multiple times and since it powered on before after I played with it for hours, I have a feeling the PCB isn't broken / damaged.

Good point on the fuse.
Jan Audio:
Put in oven after removing all plastic.
SolderOcelot:

--- Quote from: Jan Audio on November 13, 2019, 05:12:10 pm ---Put in oven after removing all plastic.

--- End quote ---
Thanks, what spices should I add?
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