Pushead

And about sparks, when you inspect carbon brushes, you should also inspect that springs that push brushes are ok. And its good idea to lightly sand copper collector with P240 paper.

Or just remove small plastic block on battery slide that prevents 4Ah battery to slide in. Of course, with taht you dont get "star" marked tool that have battery protection circuit. But its now same as yellow base without star. I think thing with yellow base was that it was allowed to use old 1.3/1.5Ah batteries. Machines that used too much current for those small batteries had black connector and that block molded in to prevent use of small batteries.