Test equipment for 1.2v cell's: a principal plan.

If you have a transformer 6V AC, 15-30 Amps max, & one power thyristor
(50-100 Amps), you can make this plan to safely recover old battery cells:

May be 12V AC ?

Set S1 for choice load time.
Push the switch to left, the thyristor gives a dc pulse to the cell.

Push the swicth to the right, the caps are disscharged...
Change the cell for the next one..

This is for Alkaline types but I expect it will do for Nicads as well!