Treadmill IMAGE 10.0 / electronics run crazy?

I live in Costa Rica and own a IMAGE 10.0 Treadmill which I bought 5 years ago. Since approx. 6 months the electronics run crazy. Suddenly the machine starts accelerating and all electronic displays show 'wild' numbers. The machine cannot be controlled manually. This happens for a few minutes or for long cycles. The problem is arising in manual mode as well as in the preprogramed cycles.
Has anyone a suggestion how this problem can be fixed?
Thanks in advance.