Hi I’m new to the site and I’m having the dreaded mmi 3g system problem on me Audi a5 b8. When you turn the system on the screen lights up for a bout 8-10 seconds then goes off. I bought a fibre optic loop thingy and disconnected the cd multi changer in glove box. I put on fibre optic loop to bypass the cd unit but when I turn mmi on I’m now getting sound /music but can’t adjust volume and as soon as I touch radio / media button on centre console the whole lot shuts off again so could I possibly have a fault on circuit board in centre console ?? I also don’t have any lights working on centre console as well. 
it’s really doing me head in. 

HELP ME PLEASE SOMEBODY 🤷‍♂️🤦‍♂️

Id recommend a diagnostic check to see if any fault codes flag up. You could also speak to an auto electrican. You might find the cheapest option is changing the system for an aftermarket one. 

Hello Steve 

cheers for getting back to us. Think I’ll try diagnostic check and see what that brings up. I’m not gonna let this beat me as it seems to be a common issue so I would like to get it sussed as to help other Audi owners having the same issue. 
cheer bigger Steve 👍