I don't remember the V7 having a non-TE option. I fly with a V7 hooked to my TE Probe and a 302 electronically compensated. They are very similar in response so I have been impressed how well the 302 works non-TE. I configured my panel so that the two varios would be independent in case I lost the TE system for some reason.

As for the B Box, not sure anyone knows how to service one now. They have tubes that are likely rotted inside so I would not trust one. I have one on the self but have never used it.

TT