Doug Rohrer
Well Known Member
I was returning from Chapel Hill to my home in western KY yesterday when my tachometer started bouncing around with erratic readings. This is the standard Van's electro-mechanical small diameter tach in an RV-9A. The needle bounced all over before eventually settling on zero. Then as I started my decent, it mysteriously started working again. After bouncing all over it now reads accurately with no fluctuation. I would have rather had it stayed failed so I could diagnose it better. Any advice how to diagnose this? The wiring is intact and all terminals tight. Thanks.