Humminbird fishfinder keeps blowing 5v fuses .Power ok to base but as soon as you attach fishfinder fuse blows

The ASD relay supply's battery power to that fuse . The wiring from the fuse to the O2 sensor has a short to ground somewhere . Look at the O2 sensor ,these wires sometime's get loose from body attachment point's an melt on exhaust manifold's or exhaust pipes .

Best precaution is an in-line fuse of a Slow Blow 5 amp near the battery or power distribution terminal.

there could be something wrong with moisture. I had a drink spilled down the back of mine and I had to clean the board cause it kept blowing fuses.

If you live in the US you can have it shipped to our service center here in the us. The address is:
Humminbird
Attn Service
678 Humminbird Lane
Eufaula Al 36027

http://www.humminbird.com/FAQ.aspx?Contentid=1768

If you are in Canada. Attached is the link

http://www.humminbird.com/FAQ.aspx?Contentid=2678

There is not a fuse in the unit. If you want to install a fuse inline with your power cable you can go out and purchase a direct inline fuse holder.

Hi Jeff,

If they're blowing as soon as it powers on, it's likely to be a short.

Pull all signal cables, lower the volume and power it.

If it doesn't blow the fuse, attach the cables one by one starting with the outputs. When it blows, you'll have you suspect. Trace it to it's dest/source to find the problem

Best regards,
Mike

There is a ground not connected or a wire open that is causing it to blow

There are a few common reasons the fuse keeps blowing:

1. The transmitter final transistor is bad, it usually is directly connected to the 12v source and not switched by the power switch.
2. The power wires were accidentally reversed I.E. positive to ground, neg to 12v. There is a protection diode on the circuit board that did its job and is now shorted. it will keep blowing fuses until its replaced.

first u will check the signal cable then check crt base [ if lot is arcking ok] replace crt base check filament volt,g2 volt,g1 vot .....etc,then u r chek 5v reg ic in supply out on smps,eprom chip and check H OUT transistor base voltage u r problem not solved about this information pls ask again to me may i help u.......

does the unit works at all?