Humminbird Unit Problems
 

I have a Humminbird 998 c SI unit that was bought in 2012. It has stopped displaying GPS position data. I suspect that the antenna and/or antenna wire has gone bad. I would like to test my unit on someone else's boat before spending the money for a new antenna. Please private message me if you have a Humminbird installed in your boat where we could do this? Thanks.

I too have an older GPS. A couple of years ago it would not operate properly at the beginning of the season. A quick google search told me it was a common issue as the internal battery that keeps the memory alive had finally given up the ship after about 10 years. I opened the unit up, identified the battery and swapped it out with a new unit. This was a soldered in battery but being an electronics bench tech that wasn't an significant issue for me to resolve. I had to perform a complete initialization set up as if the unit was brand new but the battery fixed the issue.

YMMV but its worth a shot.
Charlie T