How to Replace the Armature on a DeWALT Miter Saw

The armature is the central part of your tool's motor. It consists of windings, the commutator, a cooling fan, the shaft bearings and the drive shaft. The armature, along with the field, create a magnetic field that causes the armature to spin. The carbon brushes transfer electricity to the commutator. Over time, the commutator will wear from this constant contact. If the tool is overloaded, the armature can overheat and the insulation around the windings will burn away, creating a short-circuit. When this occurs, there will be excessive sparking from the motor brushes, and smoke or a burning smell from the motor.

Let's get started.

REMOVING THE ARMATURE   1. Remove the end cap.

a. Remove the (2) screws securing the end cap to the field case.

b. Remove the end cap from the saw.

  2. Remove the motor brushes.

a. Use a flat-blade screwdriver to remove the two brush caps.

b. Remove the motor brushes.

  3. Remove the carrying handle.

a. Remove the (2) screws securing the carrying handle to the lower handle.

b. Remove the carrying handle.

  4. Remove the top half of the handle.

a. Remove the screws securing the top half of the handle to the lower half.

b. Lift the top half of the handle away from the saw.

  5. Remove the switch and power cord.

a. Disconnect the white cord wire from the insulated terminal connector.

b. Remove the screw securing the switch to the lower handle.

c. Lift the switch assembly out of the housing.

d. Note the location of the switch wires for reassembly.

e. Disconnect the wires from the switch assembly.

f. Remove the switch and power cord from the handle.

  6. Remove the lower half of the handle.

a. Pull the wires free from the clips on the lower handle.

b. Remove the screw securing the lower handle to the saw.

c. Remove the lower handle from the saw.

d. Separate the wires from the lower handle.

  7. Remove the field case.

a. Remove the (4) screws securing the field case to the gear housing.

b. Remove the field case.

  8. Remove the armature.

a. Grasp, rock and pull the armature assembly away from the saw.

INSTALLING THE NEW ARMATURE

  9. Install the armature.

a. Install the new armature onto the gear housing.

b. Rotate the armature as-needed to engage the gears.

c. Press the armature firmly toward the gear housing to seat the retaining ring (O-ring).

REASSEMBLING THE UNIT

  10. Reinstall the field case.

a. Install the field case.

b. Secure the field case with the (4) screws.

  11. Reinstall the lower handle.

a. Route the wires up and through the opening in the lower half of the handle.

b. Install the lower handle onto the saw and align the mounting hole.

c. Secure the lower handle with the screw.

  12. Reinstall the switch and cord.

a. Connect the motor wires and the cord wire to the switch assembly.

b. Install the switch into the lower handle.

c. Secure the switch with the screw.

d. Tuck the wires into the lower handle (working from the switch toward the cord).

e. Connect the white cord wire at the terminal connector.

f. Tuck any excess wire into the rear portion of the handle.

g. Align the power cord with the slots on the lower handle.

h. Align the cord protector with the pocket on the lower handle.

  13. Reinstall the top half of the handle.

a. Install the top half of the handle.

b. Secure the top half of the handle with the screws.

  14. Reinstall the carrying handle.

a. Install the carrying handle.

b. Secure the carrying handle with the (2) screws.

  15. Reinstall the motor brushes.

a. Install the motor brushes into the brush holders.

b. Secure the motor brushes with the brush caps.

  16. Reinstall the end cap.

a. Install the end cap.

b. Secure the end cap with the (2) screws.