Looks like a cool little piece of kit. You might want to contact Mike at m-are to help you sell it. I also suggest you put the price on your advert with all the inclusions.
Northseahero,
Do you remember if it was a Microstrain AHRS? Those sensors need to be re-calibrated periodically.
In the end, if the compass is the only problem it can be replaced with a better brand.
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