Just a quick followup on my earlier post; I decided not to try and replace the RAM battery myself. I took the back off the unit and saw the button battery had a tab welded to it and it was buried in silicone on the main PCB. I probably could have replaced it myself but didn't want to risk voiding any future warranty work I may need on the unit.
I contacted Avmap support via email and they have a fixed cost, battery replacement program which I took advantage of. The cost was $125 + one-way shipping to MA. Avmap actually replaces the entire main PCB. I assume the old PCB eventually gets reworked in a factory environment.
Anyway, the whole process took less than a week and I'm quite satisfied with the result. This is the first time I have had to send my Avmap GPS in for service. I'm still very happy with the unit after about 6 years of use.
RV9A - 647JC - 300 hrs - SOLD 6/23/15
OneX - Under Construction - For Sale