I was given a 1666. The e unit wasn't working. I ordered the two pieces that attach to the drum. I pulled the entire thing apart, took the plunger out and found it to be in good shape. No rust or residue. I did take a kitchen scrubby to it, (Non Metalic) and shined it. I did this to the drum also. Both looked fine. When the two connection pieces came, I placed them into the e unit. Everything lined up nicely, I took a 9 volt battery and attached it to the e unit. The plunger went up and down on its own. No problem. The bottom connection had only one wire. That wire goes back directly to the brush area. I resoldered it. Now I have the three wires coming from the other connection. I can't figure out exactly where they go. Can anyone be of assistance?
If you ask your question in the Classic Toy Trains forum there are certain to be E-unit gurus who can give you a definitive answer. This forum is supposed to be for problems with computer/browser interfaces.
If I had the necessary expertise I'd be happy to help. Unfortunately, I gave my last E-unit locomotive to a cousin during the live fire phase of the Korean War. My present models use rail polarity for directional control.
Chuck (Modeling Central Japan in September, 1964 - 1:80 scale, aka HOj)