Wont Start, LED just flashing up for 1 second

Hey fixers,

I'm just bouth a GameBoy Color. But the GameBoy wont turn on. The LED on the left side only flashes 1 second an the GameBoy turn off.

The batterys are ok, and the contacts for the battery also looks ok.

I dont find any other who have the same problem as i, so i hope you can help me.

thank you guys