Battery Isolation Switches Dead -- NC 1095

[drakesmith]

I had my NC 1095 put on blocks for maintenance. The next day, the Yamaha technician found that none of the battery isolation switches did anything – no LED indicators and no house or motor power. I manually activated the solenoid controlled breaker switches and was able to get house and motor power (thankfully, those breaker switches contain a manual-override push button on top). However, the low-power battery isolation toggle switches are still dead – no indicator lights and no function. Unfortunately, the wiring diagram for those switches is not included in NC 1095 Owners Manual. But my feeling is that the “Lock” toggle switch provides +12VDC to the four isolator switches that enables them to activate their respective solenoid controlled breakers. So the problem I may be having is that the +12V is missing due to a blown fuse or faulty lock switch.




Questions: 1. Has anyone experienced this before? Does anyone have a more complete wiring diagram for the NC 1095? Does anyone know if there is a fuse protecting the “Lock” switch? Does anyone know how to get access to the wiring of those switches?

[drakesmith]

Problem solved. There was, in fact, a fuse in line with the lock switch that feeds the four battery isolation switches in the salon. The fuse was blown. It is a 10 amp fast acting ATC/ATO blade fuse that, in my opinion, is the wrong type for this application because it is not protecting delicate electronics. A more suitable choice would be a slow blow glass fuse. That’s because the fuse is in series with the coils in the four solenoid-controlled breakers. Those coils are inductive, and when the switches are activated, a momentary current spike is generated that can exceed the rating of the fuse and blow it (if it is a fast acting fuse).

In my case, the technician may have pressed the two motor disconnect switches at the same time which would produce even a larger spike. My recommendation would be to activate one switch at a time.

The fuse is located behind the service panel in the starboard cabin to the right of the solenoid-controlled breakers: