problem winguard road trip minimal inmotion

Iv got a inmotion road trip minimax. i have had it for 2-2.5 years about 100-120k miles of driving countless hours parked. well I'm missing channels it started yesterday on those channels it says 771-signal loss if you check the signal strength everything is 80 or above except transponder 4,12,and 20 on tuner 1 and I'm missing all the evens on tuner 2 anyone have any ideas