Desperately want to fix my dead for 4 year laptops please help

[thermometer]

Hi guys
i have few laptops which are dead oldest one is 4 years since death and recent one is 1 year all of them died suddenly.

(edit) They just died no charging no light no power on just dead

i do mobile repairs and replace visually broken parts so i have no great knowledge on how to check which part is dead in my laptop motherboard
i'll upload schematic and laptop board picture and please help me fix.
I've been trying to fix them for past 2 months but no luck.

Laptop 1 year : Sony Vaio VPCEG3AEN
Motherboard model : MBX-250

Laptop 4 years : Asus K56cm
Motherboard model : K56CM

Schematic for sony mbx-250
Schematic for asus k56cm


here are some pictures of the boards them self

Blue one is sony and Green one is Asus

This is asus












now the sony now















Thanks alot for reading would really appreciate any help

[sam_sam_sam]

Re: Desperately want to fix my dead for 4 year laptops please help

Please be a little bit more descriptive of what the problem is with both of them

[thermometer]

Re: Desperately want to fix my dead for 4 year laptops please help

Please be a little bit more descriptive of what the problem is with both of them

they just stopped working no charging no light no power etc just dead

[thermometer]

Re: Desperately want to fix my dead for 4 year laptops please help

Anyone help

[SMDFlea]

Re: Desperately want to fix my dead for 4 year laptops please help

You said you`ve been trying to repair them for the past 2 months,so list what you`ve tried. Have you checked both chargers,are you using a bench supply.Have you checked both power jacks, inspected both boards thoroughly with a magnifier or microscope for burnt/corroded parts. Does either board have power, have you tested the DC-IN mosfets , tried flashing the bios, do the LED`s light up or flash,are any parts heating up as soon as you connect power, tried different RAM, CPU`s ,Checked CMOS battery voltage ???.

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[MobileXT]

Re: Desperately want to fix my dead for 4 year laptops please help

they just stopped working no charging no light no power etc just dead

If you don't have a charging light then, you have a missing 3.3v power rail.