Lenovo X1 Carbon, 7th Gen no Display!

[Ariu]

Hello,
I have a problem with the device mentioned above. It starts but shows no display, although the device works perfectly via an external monitor. The display itself also works because the self-test shows all colors. All fuses seem to be OK, Vsys18 is also 12.24V. Has anyone successfully repaired a case like this? If necessary, I would post schematic and boardview.
Thanks.

Lenovo Thinkpad X1 Carbon: Intel I7, Type 20QE-SAY601
S/N: PF-1W6Z7X
Boardnr: FX490 NM-B861

[Ariu]

i double checked now and for me seems to be VSYS18 to low(12,24V) VSYS18 muss be at least the battery voltage when depleted (15,4V) or not? i dont know if the charging circuit is working because the battery is faulty.
is it possible that a faulty charging ic bq25700 or mosfet Q282 may cause the blank screen, because that signal vsys18 to the screen connector is coming from there ?

https://www.badcaps.net/forum/troubl...-fx490-nm-b861

[Ariu]

According to the Lenovo diagnostic app, the notebook has an error with the integrated graphics (0286 error), can anyone confirm that this is a known error for this model? is there a possible fix?

[rddube]

Are you saying you are getting perfect output on an external monitor but not on the internal monitor? Do you get bios screen (non graphic) ?

[mcplslg123]

VSYS18 at 12.2V is correct as charging ic is NVDC type.
Since you have external display,measure voltage on EDP pins.