YOGA AIO 7 27ACH6 will not turn on

[Rudolfl]

Hi all

This is an all-in-one machine. Power supply OK.
I can turn it on, but PC part does not start. Monitor turns on and goes into standby. There is a button that control video input to the monitor. Button is on the main board. When pressed, I can see selection on screen. If I switch into "cast mode", I am getting display showing QR code to connect. So, monitor works, power works, some functionality on main board work as well. I am not sure if it uses main CPU or a controller on board for this sort of things.

Fans are starting, CPU heatsink gets warm. No POST sounds. Tried to remove HDD and M2 drive. No luck

This is the first time I see this machine and wonder if anyone had any experience.

Thank you
Rudolf

[rogfanther]

Can you remove the RAM and see if it beeps ?

[Rudolfl]

Sorry, i though I mentioned this. Obviously not.

Yes, it beeps without RAM.
Removal of all peripherals is not helping.

At this stage I suspect video card module N18E-G1-B (p/n 5C50Z66222). I can only see one connector going to it. Unplugging it doe snot produce any POST. And heatsink on this card gets warm, so something is running.
I want to remove heatsinks and check power rails on it.

Rudolf