The return message I received from Garmin yesterday.
Dear Andrus Chesley,
Thank you for contacting Garmin International.
You have done all the troubleshooting available for the device. Unfortunately, there is nothing left we can do. We can no longer repair the GPSMAP 276C due to a lack of parts. Please consider replacing it with another Garmin device. Here is a link to our current lineup:
https://buy.garmin.com/shop/shop.do?cID=147
With Best Regards,
Christopher Bl.
Product Support Specialist
Marine
Garmin International
913-397-8200
800-800-1020
913-440-8280 (fax) Att: Christopher Bl., Associate #5842
www.garmin.com
Additional solutions may be found at
http://www.garmin.com/garmin/cms/sit.../searchsupport

I'll just keep it for parts.
And, think Montana in the furture . Darn I llked having a unit for each bike that I didn't have to swap when I got off one and on the other. ;-(