there is sound but command LDC not turning on please can you help


I have 2010 Mercedes W221 S550 I bought this 1 year ago and giving me keep problems and thanks to here MBWorld user and members I found many solution to fix it if its electrical issue. I searched in forum but I couldn't see 2010 Mercedes S550 Navigation Sound Radio LCD screen turned Black I tried many times its not coming. Hold on ON button for activate lcd and turns off from control panel next to joystick.

The day before its broken I need to the emergency flash light button and when I turned on flash lights LCD gone black and I turned of car and pressed * button turn on car turn of car and it fixed next day gone again even I didnt press any button, do you guys need I need to Change Control panel which is all together with joystick or LCD or both it may be fuse can fix to problem.

I tried ON or OFF command lcd screen but didnt help. still same.

Important thing is there is sound and working radio channels usb device CD can play. I didnt understand why LCD turned Black.

Please can you explain to me what I need to do fix this problem with less cost. If i need to change fuse where is the fuse if inside of dash board how to open dash board to change it. I am handy man I fixed it many times this car and still learning I do not want to break another part while fixing one part thats why I am asking.

I can upload here pictures upon request how its looks like.

Thank you,
The Best Regards,
Nick G.