Lionel 675 bad E Unit?

[edtybor]

If have a Lionel 675 engine that will only run in reverse.  I'm guessing it is a bad e unit.  Does anyone have any suggestions on how to get the e unit working properly or does it just need to be replaced? Thanks

[lionelsoni]

You say that it runs only in reverse.  Does it move backwards every time you apply voltage to the track?  Or does it move backward every fourth time you apply voltage?

[arkady]

Most often, vintage E-units are just gummed up with ancient oil residue and dust.  Before you go the replacement route, I'd say try to clean it thoroughly with some grease-cutting solvent.

 

[edtybor]

Its move like every fourth time. I also have a prewar 1689e engine that works but only powers up every fourth time or so. Is it the same issue?  Also, what in the e unit should I clean?

[lionelsoni]

The e-unit is stepping, but the fingers are not making good contact with the drum.

First, examine the ends of the six fingers.  Each should have a semi-circular shape at the tip, with the convex side of the semicircle touching the drum.  The drum might be dirty; and it wouldn't hurt to clean it with a pencil eraser if you can do it without bending the fingers.  But the problem is more likely that one or another of the fingers has part of its tip worn off or that it is no longer pressing hard enough on the drum.  You can repair a worn finger by slightly straightening the angle where the curved part begins, from the original 90 degrees to about 45 degrees.  That moves the remaining 45-degree half of the semicircle so that its middle faces the drum and gives it a second lifetime.

You can tighten the fingers by taking the thing apart, bending the fingers toward the drum, and putting it all back together.  But that's very hard to do, even with practice.  There is a way to tighten them without disassembly.  Make a little L-shaped hook from a paper clip, with the bent part about as long as an e-unit finger is wide.  Hook that under the finger as close as you can to the circuit board to which it is riveted and pull as needed to keep the finger against the board while you push with a small screwdriver in the other direction, close to the hook, to bend the finger toward the drum just a little at its base.

[servoguy]

I remind everyone that Dave Smith had a post many months ago about an E unit that he fixed.  The drum had gotten hot and was distorted, and Dave used a pair of pliers to squeeze it back into shape.  I did this to the E unit on a 2045 that I have and it worked for me, also.  I had to reform the fingers and I had to remove the drum from the unit, but it was a good midnight repair.  What happens is that the contact between the drum and one of the fingers becomes poor and the resistance increases.  This causes local heating which warps the plastic.  

Bruce Baker