rpm readings

We have a FlightDEK D-180 paired with a Rotax 912 consistently reading 20-22% low on the tachometer for the full range of RPMs from idle to WOT. RPM indications are steady with no spikes or drops. This was verified by comparison to an optical tachometer reading (converted to engine RPM in...

After installing the latest firmware on my dual SkyView Classics Touch displays, I began getting warnings that engine RPM was too high. Looking at the display it was jumping quickly up and down from 4800 to 5200+. I did have a battery that was old (and not holding a charge), so I replaced it...