Although lots of people refer to the American Flyer mechanical reverse unit as an eunit - that is a misnomer and a Lionel term. American Flyer trains use a mechanical reverse unit. If your loco is not running, here are some things to check.
- Make sure it actually IS the reverse unit at fault. Do that by disconnecting the tender and jumping the ports on the jack panel. Jump port #2 with port #3 (two inside ports). Feed your transformer leads to port #1 and port #4 (two outside ports). The loco should run in either forward or reverse. You can wire the male part of a jack panel as a tester for future use. If you do, use a red wire on port #1 and a black wire on port #4. That way, you can first check for forward by putting the red lead on the variable post and the black lead on the base post. Swap them to test for reverse. Let's assume the loco works just fine.
- Are the fingers actually making solid contact with the drum. Sometimes it looks like they are, but they actually are not or not enough to make good electrical contact. The trick is to have the fingers make solid contact, but not SO solid that they impede the drum from revolving.
- See that the fingers are in alignment so as to make contact with the metal parts of the drum.
- Check to see that the wires are soldered on their contact points securely.
- Look at the little contact knobs on the reverse unit fingers. Are they worn through? If they are, a dab of solder will fill and fix them.
- Does the drum rotate freely? If not, there may be dirt, lint or animal hair tangling the pivot points.
- Does the flapper fall back down or hang? Sometimes a small nut or washer taped or glued to the underside provides enough weight.
- Are all the metal parts clean and shiny? Contact cleaner is usually all that is needed to clean the parts.