Manuals for GPS and Sounder

[qm960q]

I have just bought a second hand boat equipped with Furuno LS1600 Sounder and Navman Tracker 500 GPS. Neither came with a manual. Does anyone know of a source to download manuals, or another means of working out the equipment? Second point is that the Navman has a lazy button. The down arrow button doesnt work - makes working the menu a bit tricky. Has anyone sucessfully repaired a dodgy button?

[finga]

Furuno
http://www.furunousa.com/Furuno/Rooms/DisplayPages/LayoutInitial?Container=com.webridge.entity.Entity %5BOID%5B0EF1EA129F5663429E13A3E2D8FE038B%5D%5D
Just select LS6100

Navman
http://www.navman.com/Navman/Templates/standardcontent____29482.aspx
And select Tracker 500