After removing the armature I cleaned the commutator. I tried just wiping the little brass tabs using a soft cloth, but that wasn’t very effective. As suggested by the Adjusters Manual, cleaning them with a rubber eraser did much better. The photo below, and close-up, shows the commutator cleaned up as best as I could.
The next step was to unscrew 2 screws (shown below) to remove field core with coils.
The manual warns to be very careful when removing the filed core so you don’t dislodge the wires soldered to the brush tubes. This particular step was difficult for me because the melted and bad wiring connected to the motor became stuck in the outlet hole/grommet. It was so bad that the grommet itself came out along with the wiring.
The next step was to clean the brush tubes. I did this with a Q-tip dipped in a bit of solvent, and used the same technique to clean the bottom of the motor casing. My brush tubes were in good shape so I didn’t remove them or the bushings – just cleaned them in place.
Next steps – take a close look at the wiring to assess what repairs will be needed.