Drill stop working after drilling hole in concrete. I can see smoke coming from drill. Now both forward and reverse does not work any more. Is the drill motor burnt out? Or is there a fuse that I can replace? What is the best way to fix this problem?

With the DeWalt cordless drills, the weak link is that the leads tend to burn (melt) off at the motor brushes when the drill is overloaded. It's happened to mine now about 3-4 times, so much so I've had to replace the wires after they got too short to put a new terminal back on them!

The only other issue is that the trigger mechanism could have failed due to the hevy load of drilling in concrete. But before you spend the bucks on that, you can easily check to see if it's the wiring or the trigger assembly.

Before you take anything apart, make sure the top speed selector is at #1, and the torque setting set to the lowest setting. (makes it easier to remember if you have the speed selector come out of the drill body)

Now lay the drill on it's side and with the battery out of the tool, remove all the screws that hold the two halves together. Take off the top half and look at the back end of the tool to see if the wires going to the motor are in good condition and not burned off the motor brush tabs. If they are, you can either resolder them or recrimp them (DeWalt used different methods for different models) with a new .25 female terminal (any auto or hardware store will have them)

You can give the repair a quick check (IF you are careful) by putting in the battery into the lower drill body and holding the drill motor, gently squeeze the trigger and see if the tool runs. If so, you've fixed it and can put the drill back together.

If the wires are good, then it's the trigger assembly and you'll have to get one from either a DeWalt Authorized service center or distributor that carries repair parts, as these are sealed units and can't be fixed (I've tried). There are some available online too, if you wish to do the replacement yourself, which is a straight forward unplug and plug operation, now that the tool is apart.

Reassemble, making sure the speed selector is in the slots on the tool body and everything else lines up correctly. Install the screws and you're back in business.

Hope you find this very helpful and best regards!

From what you describe, it could be the carbon for the brushes could have shorted the commutator. Or it could be that the motor is fried. Without tearing it down to see, it's difficult to diagnose. Should you decide to repair it yourself, this site has the parts you need.
Hope this helps.

toolpartsdirect.com/dewalt/dewalt-7.html