Mercedes BE6000 Mid Headunit wont start

[sonices]

Need help with this unit, it wont start, voltages all ok on optical no light, radio pulls constantly 0,38A current

Any info will help, thanks

When i applie heat on arround optical circuit i get red light, when it cools it stops to glow?

[gapco]

Indicate which components make the LED light up when heat is applied.

When the LED lights up does the HU work correctly ?371571