Switch V1 only Backlight

Hello friends,

I have a switch here where I can’t find the error.

The backlight of the switch turns on, but there is no picture. So no Nintendo logo and nothing. I measured the battery, it had only 3.72V and exchanged it for a good one with 4.16V.

When charging, it has 15V 0.477A.

I don’t get into recovery mode either. When I hold down the volume buttons and turn on the switch, only the backlight turns on again.

Does anyone have any tips?