Explorist 500 USB quit

I've been using an Explorist 500 on hikes for half a year. Mostly OK,
although occasionally it has me going where no one could go.

Lately my computers have been refusing to connect with it via USB. My
guess as to why is that one of the six contacts the cable connects
to--the one in the seven o'clock position--has come off. At the very
least, it has changed color from silver-gold to gray.

What's the usual way of fixing this problem? (OK, I don't really
*expect* an answer, but I can hope.)

Bart Mathias

I wrote:

Well, it turns out my "has come off" was a wrong guess. "Changed color"
was the right answer--apparently the waterproof Explorist has contacts
that are subject to sweat corrosion. Whatever, scraping the grey off to
a shiny surface, I can connect directly to a computer again (no more
need to save tracks to the SD card and dig under the battery after each
hike).