ThinkPad X270 doesn't start anymore

[rumpumpel1]

I have a ThinkPad X270 that would not start from time to time. Now it won't start at all.
Setup: Mainboard with RAM, fan, display, speakers, and USB keyboard.
When applying power the current increases within two seconds to 560 mA and stays there. No Beep Code.
Heatsink gets hot, so CPU is running, display stays dark, not even backlight is on.
All fuses are ok and all voltage rails are ok, except GFXCORE. As far as i Know this is ok though, because it is not needed for LowRes graphics like the BIOS screen.
I have flashed two different BIOSes, both with cleaned up ME, but that didn't change anything.
Does anyone have any advice on how I should proceed?

[caspian]

Re: ThinkPad X270 doesn't start anymore

Does this laptop have a dedicated GPU chip?

[rumpumpel1]

Re: ThinkPad X270 doesn't start anymore

no, it has only integrated graphics.

[caspian]

Re: ThinkPad X270 doesn't start anymore

Visually inspect all the components on the mainboard to find a damaged or suspect component.

[rumpumpel1]

Re: ThinkPad X270 doesn't start anymore

one suspicious spot I have found: https://postimg.cc/dhyZ2Vhm
it looks like someone here has already attempted a repair and was a bit careless with the soldering iron.

[caspian]

Re: ThinkPad X270 doesn't start anymore

a photo of it would help.

[rumpumpel1]

Re: ThinkPad X270 doesn't start anymore

click on the link.

[caspian]

Re: ThinkPad X270 doesn't start anymore

This damage seems serious and can be the cause of the black screen. you should check this section of the mainboard according to the schematic to discover any defective component there and replace them.
However, it is also possible that the components in that section be still fine.

[rumpumpel1]

Re: ThinkPad X270 doesn't start anymore

The shown parts are responsible for the 3,3V supply of the display. This voltage is present at the fuse F2, so I assume that the components in that section are still fine.

[caspian]

Re: ThinkPad X270 doesn't start anymore

yes, probably.
Now you should trace signals according to the following thread:
https://www.badcaps.net/forum/showthread.php?t=44779