My son has stuffed coins into my Concert II non bose (A3 Sportback 06) which have all been removed now by opening up the unit however there is no sound. Unit works ok, CD player, IPod connectivity, Radio, Phone all work just no sound so I suspect the amp chips at the back left are ******. However before I get an exchange unit, is there anywhere else in the Audi audio wiring loom that could have been fried, or tripped/fused? I don't want to pay Audi service £50 for diagnostics on-top of £305 if I know the unit's goosed.