NMEA plotter to VHF problem

[Jizm]

Calling electronics wizards....

There is no position display on my icom m505 from my standard horizon cp175c plotter. Had a look behind the console and noticed I had snagged the NMEA connections with the new grab handle I fitted. Repaired the cable but still nothing, all connections are correct etc.
what voltage is NMEA?
Do plotters have an internal fuse to protect the output?

[Daniel]

It's very resilient, usually. And there's no fuse to speak of 😟.

It's 5v ish; but you'd need an analogue meter not a DVM as the needle will flick if there's data. You can't typically see this conclusively on a DVM.

One of our most used tools is an old laptop with a cut down rs232 cable and hyper-terminal. We can instantly see if there's nmea data.

Not sure what advise to offer...

[Jizm]

Only have a DVM at the mo. But I am a bit confused as to why it's packed up as it's been clamped for a year and not really shorted out.....
I have got into the data output page of the plotter and can only see output on one of the three port pages....
Weird....

[Last Tango]

If you wire an LED in series with a resistor (about 1k ohm) try it both ways round you will see it "flicker" about once per second with the data. Better still if you can borrow a Breakout box eg "Interfaker" again, you'll be able to see the data.

[Jizm]

Ok cheers guys.
Going to try and borrow a plotter from some where and see if the radio displays the data with that.

[Jizm]

Sorted it😊

Iffy connection on the back of the potter.

Took off the bracket and cleaned it. All ok now...