Cell replacement - OK to disconnect old cells?

[Fusion]

Can anyone with experience in cell replacement recommend whether or not its OK to fully disconnect the balancing board? The info online differs, either saying no, keep the board "alive" or yes, jump start the board after replacement with a fan.
The batteries I'm dealing with are originals from T60/W500 era, 6 and 9 cell.

Thanks!

[RealBlackStuff]

I've never done it (and never will) but the tendency and advice on the forum is to keep connections ALIVE.
- Connect the new cell parallel to the old one.
- Only then disconnect and remove the old cell.
Don't know anything about a balancing board, never heard of it.
I assume that is not a Segway...