I unfortunately have Navico Corus instrumentation on my boat and the depth sounder has ceased to function. The transducer, which is of the 'in hull' type has been checked in another boat and works fine. All four multi-data instrument heads show identical readings when set to depth. That only leaves the active depth module to check out - it's an ATSD600 model, no longer made and no spares available. This unit is now in a repair shop in Marmaris, Turkey and the owner of the shop tells me he cannot repair it without a circuit diagram. So......my question is....does anyone know where I can get such a diagram? Or does anyone know of a place in UK that could repair it? Any help would be appreciated. E-mails to Simrad Navico bring no response - they are not interested in the private sector anymore it seems.