There's no info on Lionel's web site about your specific unit yet. But, except for replacing the old mechanical E-Units with an electronic one, they haven't changed much over the years. The web site does have some info an an earlier unit, 6-18446, with an electronic E-Unit that should be useful.
You can download the .pdf file containing an exploded diagram of this unit from the Customer Service area of Lionels web site. Click on the "Parts List & Pictorial Diagrams" link on this page, then enter 6-18446 as the search criteria. That should take you to the page where you can download the diagram. You can also use this number to get an owners manual from the "Owners Manuals" link on the Customer Service main page.
Some, not all, mechanical possibilities, in no particular order:
- Check that the impeller drive pulley on the extended armature shaft wasn't pushed too far down. If it is, it could be binding against the brush plate assembly.
- Check that the worm gear end of the armature shaft is properly seated in the thrust bearing located in the hole in the chassis. If it's not, the armature windings can jam against the field coil.
- Check that the worm wheel on the drive axle hasn't been pushed to one side of the axle. If it is, operation will be erratic. More so in one direction than the other.
- With the drive belt off, check that nothing is binding in the impeller assembly.
Some, but not all, potential electrical possibilites:
- The 104 electronic E-Unit (PN: 610-8446-256) got zapped at some point, and is flaking out.
- One of the insulating washers (PN: 610-8049-076) used to mount the E-Unit motherboard is damaged, creating an intermittent or hard short.
- The Collector Insulator (PN: 600-0041-026) is damaged, creating an intermittent or hard short between the collector assembly and the chassis.
- The primary power feed wire, attached to the tab of the collector bracket that pokes up into the chassis, may be coming loose or have a cold solder joint.
- One, or more, of the wires in the wire harnesses that plug into the motherboard may not be seated properly in the plug.
And never forget, there's nothing that says there can't be more than one problem at the same time!
Len