A note on TruTrak magnetometers.  A friend of mine recently sent his DigiFlight II VSGV to TruTrak to have the display replaced.  (Apparently display failure has been a somewhat common issue with these units.)  While he said the new display is much better than the old one he was surprised to find that TruTrak, without informing him, had removed the magnetometer from his autopilot before sending it back.  He is not happy.

Tom Gourley