Dewalt DCH253 drill loses power - Dewalt Hammer Drills: Hammer. 18-Volt Cordless 7/8 in. SDS Rotary Hammer Tool Only DC212B

It's common for the brushes to pop out of place causing partial contact to the armature . If there not damaged you can simply slide the brush and holder back in place or replace if damaged. .another common issue is the leads going to the motor can become damaged . Most of the time you can clean the terminals and reattach them to the motor .if loose use pliers to carefully squeeze the terminals to the contacts on motor . .I hope that helps !