Stumbled across your post. I have had 2 of the gps17's fail. The 2nd one just failed mid July. I replaced it with the gps19 because we were cruising and didn't have the tools. Opened it up today, there is a dead battery, that can be replaced #1220. The cover unscrews (big help to know) but you'll need a strap wrench. I didn't know that , I sawed the grove around. Inside the top box on the circuit board is the battery. I m pissed that I had to rip out all the wiring to install the new antenna plus pay $200 for the antenna over a $2 battery. AAAAARRRRGGGGGHHHH.