Despite my friend Bill's opinion, Sentrys are actually pretty good chargers. Mine did a beautiful job of maintaining two 32 volt banks on the Hatteras. One thing that makes them good is they are completely field serviceable; most factory certified CruiseAir
technicians can fix them. The customer service is pretty good over the phone too. The last number I have for them is 804-746-1313. I am not familiar with the G series chargers, so best to contact them. It may be as simple as having a blown DC fuse.
PS: Bevins, replacing the control board usually works better than trying the calibration routine.
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"