purchased a lowrance m52i recently and am well impressed with it apart from poor (non - existent?) keyboard backlighting. Anyone on our new look forum have similar problem.
It should have 3 levels of backlighting. When you turn the backlighting on, does the screen backlight work OK? If so, the LEDs lighting the keypad may be faulty.
screen backlighting ok.
does your keyboard lighting display symbols on keypad? this one doesnt
just been told by distributors (silva) that m52i doesnt use leds (the amber backlight described on label) - something like cold fluorescence
what coo;our is your backlight?