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Lowrance problem - report, not request
Took a couple of days off, and decided to spend 4 days diving in Monterey (Calif, USA.) Weather didn't exactly cooperate, but that's another story.
What did happen was that, on Saturday, just before leaving the dock, my GPS (Lowrance LMS-520C) suddenly decided to give me a "Position Lost" error message, followed by a "GPS Module not Responding" message.
A bit of background here: The Lowrance unit uses an antenna that connects to the GPS via a "plug and bayonet" connector (I.e. you align the key, push the connector on, then twist the collar on to lock it in place.) As simple as that sounds, the antenna is part of the NMEA 2000 network, so you also have to connect the network power wires to a 12V power source. Any other sensors you may have (I have a fuel management sender; you can also get fuel tank level, radar, and a bunch of others) get connected into the network as well, basically daisy-chained into the antenna cable.
So, given the failure mode, I figured one of two things had happened: Either the antenna had bit the dust, or the network wiring had gone away. Since there was no way to troubleshoot the antenna in situ, I concentrated on the wiring.
The wires for the network power come out of a similar connector (if not the same connector; don't remember) as the antenna; but are simply exposed wires that the installer is supposed to terminate to 12V. For some dumb-ass reason, Lowrance has decided to use something like 24 or 26 ga stranded wire for these connections. This causes a couple of potential problems: If you use crimp connectors (as the ABYC recommends), the small diameter of the wire make for a tenuous connection, as the crimps don't reliably grab the conductor. If you decide to solder the connection, the small conductor diameter and solder makes for a connection that is very stress-prone.
Almost immediately, I found a wire that had succumbed to both problems. Despite being in an area that was not subject to much movement, the wire had broken at the spade connector. Attempts at opening the connector and recrimping were only partially successful; only when I soldered the wire onto the connector did the problem fully resolve itself.
I don't see why the wires for network power should be so small. I understand there is very little current going through them, but handling and durability suffers with this size wire, and the loss of a connection brings down the entire NMEA network. Not a great design, IMO.
Anyway, that was just a heads up for other Lowrance owners. Hope you don't have to solve similar problems.
jky
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