Phil:
Are the ADAHRS physically close to each other, like stacked? If so, the compasses should agree pretty closely.
If the ADAHRS are far apart, perhaps some electrical circuit is influencing the "standby" ADAHRS.
The compass calibration process does calibrate both ADAHRS at the same time, but won't compensate for such a large discrepancy between the two.
Contact Technical Support at 425-402-0433 or support (at) dynonavionics (dot) com to arrange for a Return Material Authorization to get the "standby" ADAHRS back for service.
Note that your SkyView system has assigned the roles of
PRIMARY to the SV-ADAHRS-201 S/N 2390
and
STANDBY to the SV-ADAHRS-200 S/N 2968
So it sounds like the unit you would send back is the SV-ADAHRS-200 S/N 2968.
I have 2 Skyviews, a 10" and a 7", with Dual ADAHARS installed in my AirCam. After boot up they both work fine for about 30 seconds. Then I get a Compare message. Initially both compasses agree and then the Standby compass is off by nearly 180 degrees. I did a compass calibration on the 10". Not sure if I need to do one on the 7" that is connected to the Standby ADAHARS.
Attached is a photo of the problem.
Phil in Tucson