C 80 Linearization issue

[BurleyCove]

I was trying to help a buddy fix an issue with his C 80 and got stumped. The display shows the vessel icon about 180 deg off. We tried to go thru the linearization steps in the manual and the system would never complete the process Looked for any potential magnetic or metal interference and found nothing but moved a lot of stuff around. WE were going the specified less than 2 knots and turning slow. Tried all kinds of combinations Now when traveling on plane the boat icon is 90 deg off the heading but every few minutes the display rotates thru 360 plus degrees for no apparent reason., Anyone seen this before? Is the compass sensor bad?

 

[BurleyCove]

Fixed it. The compass sensing unit was originally installed with double sided sticky tape. It had fallen off and was dangling. Once we got it installed right side up the system aligned and is working perfectly.
Added a couple of screws to teh compass mount.