[wswartzwel]

Voltage check coming from the rectifier would be next.... You can also get ohms readings across commutator to see if there are any open windings... as well as resistance from each commutator to the armature shaft to see if there is a shorted winding. You should be able to find manufacturer tag and google a parts list online to locate the right rectifier... it will need to handle whatever amp rating the motor requires. sounds like a fun project.