Instruments and fuses, a little help please.

[djousset]

Both my depth sounder/knotmeter have gone out at the most inopportune time. Clearly an electrical issue. Behind the main panel I see three fuses, one of which I think might go to the Datamarine. It's labeled BUSSAGC2A, which I do not have on board. I'm bouncing around like crazy on a mooring today and I would feel a whole lot better with this thing up and running before I move on.
A) Is it likely there is a fuse for this instrument?
B) If so can I replace it with an AGS-15A in a pinch? Guessing no....

[flee27]

I is a good assumption that the instrument is fused. When a fuse blows there is always the question on why. If all is OK and fuse blow from some random event than no harm will come temporary replacing the fuse with a larger one. It is generally not considered good practice but sometimes one must do what they must do. Also remembering a wire is fused to protect the wire and not the device it powers. If I were in your situation I would use the bigger fuse. Put it in and assuming the instruments work, leave them on for a few minutes and carefully feel the wire around the fuse to feel if it is getting warm. If not I would say all is good. I would make it a priority to replace with the correct size fuse asap.

It is also possible that the actual device is also fused at the device. This fuse is specified by the manufacture and is there to help protect the device.

Good Luck
Foster

[Cheechako]

a 2 amp fuse for an instrument seems VERY high. I wonder if someone already put that in there ....way oversize?
Or that fuse you mention maybe powers more than one thing? Trace what it powers, maybe something else is blowing it?
I agree, if a low draw instrument is blowing fuses, something is shorting somewhere, check wires, wire ends etc for chafing etc.
A 15 amp is way overkill. Do you have the instrument manual? what should it have?
Where are you? AGC fuses are very common.

[Rumrace]

I was going to say if you know why the fuse blew you could tin foil to limp for supplies. Otherwise you run the risk of destroying equipment. I’d check every connection for continuity and corrosion first. I’d check the hull grounds and verify polarity I’d disconnect the most recent thing added to that circuit.

[djousset]

Thanks all, I topped off the batteries thinking it might be a low power issue but still no luck so I replaced the fuse, which appears good, with a 15 amp and everything came back up. I'm out at an island with no access to an appropriate fuse so for now this will have to do. I'm monitoring the wires for heat. I was hoping to jump a USB charger off this connection but now have second thoughts.