Lenovo Yoga 14 not turning on with batteries connected

[RethoricalCheese]

Model 20DM-003TMS

Laptop doesn't turn on (only lights up keyboard but no display). It turns on when I disconnect charger, battery and CMOS battery and reattach them. After I shut down, I need to disconnect them again.

Just tried updating BIOS via USB to the newest version but it did not help.

Any idea where to look at? It seems like a common fault on these models but I haven't found a solution yet.

[RethoricalCheese]

Re: Lenovo Yoga 14 not turning on with batteries connected

Looking how this model has a safety switch on the motherboard telling if the backplate is on or not and that switch often stops working properly, I tried shorting the pins to make it switched on all the time.

Sadly, did not fix the problem. Still need to remove power to start it up again.

Edit:
When charger and CMOS battery are disconnected, I can get it booting by holding down the reset button underneath the laptop for a few seconds.

[appie1206]

Re: Lenovo Yoga 14 not turning on with batteries connected

And did you fixxt it?