MacBook pro not booting

Hi there, im new to macs so i need some help and advice please

I bought a faulty MacBook pro off eBay.

It is immaculate externally and came without a battery, charger or HDD.

I've purchased a charger and a battery. It didn't used to power on with just the charger but now with the battery it does.

However the screen doesn't light up at all nor does the keyboard.

The disc drive spins and noises are being made but there is no signs of life.

Obviously it won't boot without a HDD but surely the screen would light up?

Do I need a new logic board?

Thanks in advance