hi all,

at a loss here as bought a second hand mercedes w169 a class 2005 plate as a car to use in spain on pick up from garage it was found the radio head unit was working but has no sound.
the car has a harman kardon 12 speaker system with fibre optics (b2b not most) as you can tell i have been researching this extensively as the garage whilst trying to sort it out are getting nowhere (its been with them more than we have had use of the car for the last 3 months!!)

so i made the decision to look at alternative aftermarket solutions but with a dead amp it appears i will have to scrap the entire harman kardon sustem due to the fibre optics and complications they bring.
a replacement amplifier is over £1k and the head unit does not have any navigation so on an old car i need a cheaper solution.

i bought an ATOTO s8 head unit and it arrived today so i wired it up to just the acc. permanent live and of course the ground terminals on the quad connector but the unit would not fire up!!!
i suspect a faulty unit but could there be another complication i am missing.
i am sure i have the right connections.

the plan was to try to utilise the speaker looms by redirecting from the amp location in the boot, replace the spaeakers with 4 ohm speakers instead of the hk speakers in the doors only, fit a canbus adaptor to be able to use the SWC but using only a 4 speaker system.
i believe the fibre optic signal is generated by the old head unit which will be taken out obviously along with the cd changer and amp (so in effect bypassing the whole system.

am i missing something or do i have a faulty head unit from the supplier??

its going back tomorrow if no good!
TIA