TZT2 not recording tracks

This ought to be an easy one. After a summer layoff I noticed that my TZT 12 is not recording/showing tracks (though it did so this spring, and old tracks do show up). When I tap the boat icon I see Track:ON and Automatic Track Deleting is ON.

Unlikely to be a cause, but for the record, another MFD (TZT 9) was sent back to the factory for a replacement of the display and re-installed. It is showing/recording tracks just fine.

Where do I look?

I suspect when the track was recorded the auto delete was turned off and now your track memory is full. I would back up any tracks you wish to keep and then delete all your tracks to empty the memory. If it still doesn't record tracks, I would suggest you back up all your user data and factory clear the display to start fresh.