Yamaha 75hp. gauges not working

Hi I am not that technical, but I have a 75hp 2 stroke outboard. Have also a tacho gauge that shows oil level with trim level, tacho worked upto 27hours then flashed and died, oil level worked but never saw the trim gauge work. What can I do to troubleshoot the gauge? or is it not worth it? actually planning on reverting back to analogue gauges. any help is greatly appreciated, as the motor is on a hydroambulance and therefore need a fix asap.

[boats.net]

Check inline fuse on yellow wire between key switch and tach, should have 12 volts between yellow and black wire at tach with ignition key on.