The backlight is CCFL. It is not as bright as the later LED backlit models.
The bulb may be weak.
Additionally a CCFL unit is not a good choice at the bow since the display is tilted up for viewing. Does OK for 2D sonar and mapping though.
You can try a brigher SI color pallet to see if that overcomes the lack of brightness.
That is why there is a model 998c HD SI Combo. The "HD" means it has LED backlighting and is brigher than the previous 998c SI Combo and the 997c SI Combo.
Edited by Wayne P. (07/06/15 01:28 PM)
Humminbird Helix 12 CHIRP SI, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2, 360, RC-1