DeWalt miter saws are designed for durability and really hold up to being lugged around the jobsite. Any moving parts, however, are going to wear over time and eventually need to be replaced. If your miter saw is experiencing symptoms of power loss, intermittent power or if you're seeing sparks/smoke when it runs you may have a problem with the armature. The armature and carbon brushes spin against one another, wearing with use, and after heavy use can degrade to the point that electricity is unable to transfer evenly between them. You can inspect your brushes first to see if they're worn, but keep in mind a damaged brush often indicates a problem with the armature - so we recommend replacing them together. This is a simple job you can do yourself, saving you hundreds of dollars on a replacement.
Step 1: Remove the belt cover.
Step 2: Remove the belt.
Step 3: Remove the motor end cap.
Step 4: Remove the brushes on either side of the motor housing.
Step 5: Remove the motor housing.
Step 6: At this point the motor housing should pull free from the saw body. Remove the motor housing and pull the armature out. It may be stuck in there tight, wiggle back and forth or tap on end to loosen.
Step 7: Be careful with the armature assembly and fan, as the fan is plastic and not sold separately - if you break the fan, you will need to replace the entire armature.
Reinstall in reverse order, and that's it!
If you have questions about any part of this process, try watching this how-to video we made on replacing the armature in a DeWalt miter saw.
Parts:
DW716, 779, 780, and 782 Type20:
https://www.mmtoolparts.com/store/n143958-armature-assembly-dewalt
DW706, 716, 718, 780 Types 1-4:
https://www.mmtoolparts.com/store/dewalt-armature-assembly-n027083sv
DW704, 705 Types 4A - 7:
https://www.mmtoolparts.com/store/dewalt-armature-kit-5140021-93