Garmin GPSMAP 740 chartplotter on the way out? - 2018

 You can see that around the edges white is starting to show
 on our Garmin GPSMAP 740 chartplotter. 

We wrote to Garmin and they think it's just age. We purchased a backup navigation app  for our Samsung tablet (Navionics).

December 2018 -We are currently in Paradise Village Marina in Banderas Bay Mexico (by Puerto Vallarta)

 Yikes!