Mercedes c180 head unit fault ??

[Frazzman-c180]

I have recently bought my mercedes c180 kompressor, it has the head unit that comes with tv, satnav and bluetooth calling the radio works also the cd player works, but there is no visual in the display so this means the satnav and tv do nit work i was wondering if anyone has had a similar situation if it can be fixed ect. Or if requires a new head unit

 

[television]

You can pick up good working ones on Ebay and cheaper than getting the old one repaired.