Does the Garmin Oregon have any diagnostic screens?
Yes. Select the Satellite Tool from the Main Menu. Press and hold the upper left corner of the Satellite Tool page for 5 seconds and the Oregon will display a diagnostic screen. There is a button at the bottom of the diagnostic screen that will allow you to page through various display test screens. You will need to power off and back on to exit diagnostic mode. A second set of diagnostic screens is available through the Trip Computer. Press and hold the lower right corner of the Trip Computer. The brings up a page of most recent exceptions, tapping the trap exceptions seems to give a register dump. The bottom of the screen gives some memory utilization statistics. Tapping the lower right of the screen cycles through what appears to pages of tasks and memory utilization.