When starting up only back light lights up

Phone: Xiaomi redmi 2.

After changing the front glas of the phone it doesn't start up anymore.

When i push the power on button only the backlight lights up shortly.

Even the 3 button at the bottom on the screen don't light up, but when clicking on it, the phone vibrates.

When i charge the phone the led (at the bottom) light up.

Could anyone indicate what te problem could be?

Best regards,

Jeroen