Cateye Padrone computer not recording properly

[Anthony MTB]

So, my Cateye padrone computer was working fine, then it stopped recording above 9kmh. I replaced the receiver battery and then it worked fine. Few months later (now) it won't record above 29kmh when riding. I replaced both batteries and did a full reset, and it worked for like a 2-minute ride, then next morning (a race too!) it stopped working again. Funny thing is if I spin the wheel with my hand, it records any speed fine, but when riding it won't go above 29kmh. And the connection distance is fine with both computer-receiver and receiver- magnet. Can anyone help me out?