Electronics wipeout

[trentsidetimbo]

Hello everyone!!
New to the forum, basically looking for support with this head scratcher....
Our club Rib has spat all its electronics out dead,,, nothing.
No fuses blown and voltage present at 12.5v
Garmin FF blue 100 /nasa sx35/furuno gp31 and engine tacho all dead.....
Nav lights and bilge pump ok.
All share a common feed from the battery thro switch /fuse panel
Checked voltage with engine running, high at 17v but stable thro rev range.
The garmin spec is 10-18v with overvolt protection and the furuno is 10-30v so I would have thought that they would have at least survived any mischief!!!
Can only think that a big surge has got onto the system somehow
Anyone had a simular occurance?
gratefull for any ideas!!

Thanks in advance,,,,,,

[Polwart]

Originally Posted by trentsidetimbo

All share a common feed from the battery thro switch /fuse panel

and therein I think will lie the problem! (Presumably there are separate switches for pump and lights)

To kill 4 electical units (through fault or overloading etc) all at the same time would be unluckly. I suspect you have either blown a fuse you don't know exists, got a dodgy switch or a dodgy connection somewhere.

I have found sometimes the easiest way to trace a fault like that is to draw a diagram and then very systematically identify which bits of the circuit are definitley connected/live etc. Colouring over live wires with a red felt tip and good earth connections with a green felt pen - usually at some point you get the "doh" moment where you discover the fault. (in this case a red and green line should never touch).

[Jizm]

Do you still have a ground at the electronics?

[Biggles]

I'm not an electrician. But a marine electrician told me that with marine electrics you are usually better working backwards. IE from the earth back.

Check all you earthing points. Get a multimeter and use that to make sure you have continuity.

[trentsidetimbo]

Originally Posted by Jizm

Do you still have a ground at the electronics?

Supply is present at all units connectors!!
This is why I am thinking on the lines I am.
I am aware that modern meters don't offer any load so can kid you along a bit, but when the pumps /lights are on, drawing 10amps approx, the voltage is still present and stable at the instrument connectors.
Thanks to all for the responses,,,,,,

[Jizm]

Biggles is spot on (and I am an electrician!)

Check continuity from the main battery earth to the earth connections on the electronics. You are looking for a low reading with your multimeter <2 Ohms would be ideal.

[Jizm]

You must have responded at the same time as me!!

Anyway is there a possibilty of powering the electronics from an independant supply, booster pack or spare battery connected directly to the unit? That will rule out the boat wiring.

I would offer to have a look for for you but you are a little far away for me to pop round!

[trentsidetimbo]

Originally Posted by Polwart

and therein I think will lie the problem! (Presumably there are separate switches for pump and lights)

To kill 4 electical units (through fault or overloading etc) all at the same time would be unluckly. I suspect you have either blown a fuse you don't know exists, got a dodgy switch or a dodgy connection somewhere.

Each individual item has its own switch/fuse on a common fed panel,,,,
I agree it seems odd, but its strange how the non-electronic kit has survived!!!

[trentsidetimbo]

Yes I have tried an independant supply direct to each item and all are dead,,,,


I'm wandering wether the ignition has got onto the system somehow,,,,????

Looks like the kit has got to go for postmortem.....

Any recommendations????

[Jizm]

Well if no luck from an independant supply then it would appear your items are indeed dead! I would send the fishfinder back to garmin to see if they can repair it and what the probem was.