ORIGINAL: DBCherry
Unless you're real good with soldering I wouldn't bother trying to determine the bad cell, just replace the whole pack. Even if you replace the bad one, there's a good chance that another of those cells will go bad soon.
Dennis-
Yes, unless it's a Hitec "Focus 4"Tx, then you can just slide a new one in the "pack".
Been O.K. for two years now.
Jetts