Hi. On my Perkins M135 the trip counter on the original dashboard has a fault. When exceeding 1000 rpm the display drops to 0 and stays there without twitching. When reducing the throttle below 1000 rpm it works again. We have replaced the alternator, it is new; the "W" connection is OK. The error has remained. Of course, the engine hour counter no longer works either. Does anyone have any ideas? Thanks for your feedback. Greetings, M.F.