My lionel 2026 died. I cleaned the commutator, bushes and such but it just hums. Can I bypass the e-unit to check the motor and field?
When you put the brushes back in you got to make sure you have the proper spring tension on them.
Try backing off on the brush plate screws a hair. If the engine runs then the brushes are to tight on the commutator. Or the tension can be the opposite and do not have enough tension on the brushes too.
Try first backing off the brush plate screws a little and then try to run it.
Also make sure the lever on the e unit is making contact when you move it.
Edit.......A copy and paste you can try.
The basic wiring of the AC motor is power runs to one side of the coil, through the coil, from the other side of the coil straight to one motor brush, through the motor and back out of the other brush.
One would normally find that the center rail collector powers one side of the coil, and the second brush is 'earthed' to the chassis, and therefore to the outer rails.
To bypass the reversing unit, use a length of wire with a crocodile clip at each end. Clip one end to the coil (the side that isn't connected to the center rail pickup), and the other end to the brush holder that isn't earthed to the chassis. The motor should then run, irrespective of the reversing unit.