Tough luck. These Beosound 4’s does not seem to be as easy to work on as the BC2300/2500/BS Ouverture/BS 3×00 system
I agree – they’re far too modern for my liking.
Looking in the servicemanual for the BS4 something about modules being registered to the BS4 when powered on for more than 12 hours or the Pin code being activated/deactivated which sounds like a lock in between the main PCB and the other components which could probably cause trouble if one module is malfunctioning.
Thanks @madskp I hadn’t spotted the 12 hour comment! Because I disconnected several ribbon cables when dismantling, I will power the unit up and leave it overnight in the hope that this may cause the modules to ‘re-register’. I don’t hold out much hope, but worth a try!
I also noticed in the servicemanual that there are some pictures showing different points where certain voltages should be available. If you wan’t to dig further one option could be trying top measure if these voltages are present.
The manual also says that the BS4 should be in CD mode when testing voltages. I can’t get it into that mode, or indeed any mode other than standby!
The service manual does also mention a removable/replaceable EPROM on PCB06, but as you can see in my photo, where the metal cover is removed, none of the chips look to be removable.
I’ll persist a bit longer, but to be honest I don’t like working on it! Those pull-out ribbon cables are very tricky, and the very sticky outer case leaves black marks all over your hands (and workbench) when handling it. I am adamant that I won’t clean it until it shows signs of life!
