it may pay to check rather than assume the ground connection Steve.
if you need a new battery then do that step first and see if that's enough - the DVR2 has a connection that can change it from 6 to 12v, so no need to change both at the same time. if you check your wiring make sure if has a fuse installed.
there's a whole very long thread on 6v vs 12v:
https://www.a7a10.net/forum/index.php?topic=7931.0changing volts also means changing bulbs which is a hassle, but there are a lot more 12v batteries and bulbs than 6v ones.
FWIW my a10 is still 6v and i kind of like that. your old b33 is 12v and i like that too - in fact i just stuck a 12v AGM battery in the b33 so i could use its 2xcyclons in the (6v) a10 when that battery died recently.
