I have two 997s right now, one NVB and one not. The chip works fine in my unit. The NVB unit is one I am testing out for a guy, putting it thru its paces. It was involved in a storm here on July 18th, that found the boat it was mounted on upside down in the water with a 997, 757 and an LCX 27 still installed in the boat. (Over 200 boats got loose in the storm and ended up piled up on the south end of the lake.) Both Humminbirds came right up when I powered them on, although it took the 997 a while to lock on, but there was a considerable distance from where it was last powered. The problem I was having was on the first day and to be truthful, I didnt leave it on for very long (maybe half an hour) and I switched back to my unit. I messed with it that night in the shop that night, and it worked flawlessly the second day of the trip. I dont have a power cord for the LCX 27, but Im working on that one also.
Impressive pieces of equipment, thats for sure.