I have one AF3400 and one AF3500 installed. Two magnetometers. Got the right side magnetometer alignment done with out problem. The left side stopped at step 13 with a message that says:

Magnetometer calibration cannot continue
EFIS unit requires a power cycle
Power cycle unit or press return to quit calibration.

While doing the alignment for the right side, the left EFIS heading was moving around. At one point it's heading was the same as the right side, but I still could not get it to calibrate.

On a previous post did I read correctly that if you have two AHRS you need to have two OAT probes? That doesn't seem to make sense since the units should talk to each other.

Last question: how do you zero out the tach and hobbs time? My EFIS shows 65 hours on the tach and 87 on the hobbs. Today I did my first engine start, so I'm confident those times are not correct.

Thanks in advance,
John