This is a long shot, but Y!A haven't let me down yet. I've recently picked up a DT50 portable PA system, with a non-working VHF microphone receiver. (Not a problem, it was free - the worst I've got is a very loud FM radio) I think that the VHF switch needs replacing. Does anyone have a circuit diagram?

Do you think I'd be asking the question if I hadn't tried the manufacturer? They'd rather sell me a new one.