lionel sticking E unit

Have you tried locking it in reverse to see how it runs?

Lights go out?

3 position or fwd/rev.

Clean brushes, tubes, good springs, clean armature plate gaps?

Direction should not effect the e-unit coils pull. A directional problem may be the isuue though; the drop out a symptom. A bad eunit coil would drop out both directions if the windings were bad.

thanks for the input guys. after my post I put that loco into reverse then bypassed the E unit and it ran perfect I did the same thing in forward and it ran perfect so I am convinced this is a flakey E unit

If the eunit pulls but no power flows to turn the motor for long, the contacts might have been overheated and curl when hot now. Rebuild kit time.

Look for loose wire scrap on drum, under finger, or bent contact finger etc.

A short anywhere could also cause the e-unit to drop, we are chasing the rev. fact, but it may be coincidence; don't forget.

Replace both sets of contacts and the drum.

Here is the proper spreading tool for servicing 'E' units, available from The Train Tender.

Here are 2 nice video tutorials showing the rebuild procedure.

Part 1

Part 2

Larry

A short. You could pull every drum contact wire and the eunit should still draw the plunger.  Changing motor direction wont change anything about the e-unit coil or its feed power either.

Only a very heavy draw that drops track voltage/amps to under 3-5v should make the coil drop out,.... or a bad contact at the e-unit on/lockout lever.    The drum/motor are a different circuit altogether.

If the motor bushings are oblonged your armature might be rubbing the field only in rev. . That could cause a big enough short to drop the eunit out too.

@Adriatic posted:

If the motor bushings are oblonged your armature might be rubbing the field only in rev. . That could cause a big enough short to drop the eunit out too.

@rebuilder posted:

...after my post I put that loco into reverse then bypassed the E unit and it ran perfect I did the same thing in forward and it ran perfect...

As was mentioned earlier.    Contact cleaner will clean the contact fingers and drum

with all the posts i’ve read on strange E unit problems I may try my luck at converting to an electronic E unit it can cost a little but takes out the mechanical E unit too so this could be the way to go and from what I know lionel dropped the mechanical E unit design some time ago

Remember KISS (Keep It Simple, Simon). Maybe try that contact cleaner first.

@rebuilder posted:

...... will not cycle the E unit.....

I assumed it didn't even try to cycle once it stops. I asked about the headlight for that reason too.

If it tries to cycle, pawl angle, drum/teeth or contacts, sure.

If the coil won't pull, the mechanical contacts are not the issue unless shorted out; normally easy to clear if there is just some conductive crap in the points.

Don't even have all the answers and you've focused ahead of the logic chain....does the coil drop out of cycling or just the motor...The light usually bypasses the eunit too, it going very dim also points to a short.

AND/OR  folks aren't sharing WHY they've come to their conclusion.

You can't use "any old board" to reverse. An open frame motor needs a high amp board. If your problem isn't the e-unit, it's a waste of time and money.

The slug in the coil can also become magnetic and stick in the up postion in neutral, but it doesn't really explain the drop out.  Id think a roller issue could also short directionally, arm or wire.

Bypass the e-unit, but leave it mounted and the coil active.

Does it the coil drop out running in rev. now?... fingers are shorted if it doesn't. Rebuild.

If it does drop out, I could only guess the coil was bad when exposed to the rev. motor field changes. I.e. about to fail outright.  That would be a needle in haystack fail though.

Just for kicks, reheat the soldering at wires that go to the coil. Don't trust your eyes for cold solder joints, reflow them.

@Adriatic posted:

The slug in the coil can also become magnetic and stick in the up postion in neutral,..

Just run it on AC for a while, that should degauss it.

I think this E unit has a coil problem with the lever switch in the active position I power up the track the loco goes a very short distance then stops with track power still on I tap on the top of the E unit and it energizes again so I strongly believe it is replace time

I won’t try to save this flakey E unit so i’m buying a rebuild from Jeff the train tender got one from Jeff for another love awhile back and it runs flawlessly

I think in the future if I do any more MPC without an electronic E unit i’ll convert it just a bit of cost

1. It's a simple switch and does lose connection when loose at the pivot point rivet. Pressure of a connection is important.
2. Set the rivets more, and/ or bend the arm carfully so when on it is tight to the contact pad or rivit and pivot post. (don't pry to bend and lift the pivot rivet, use pliars to hold that part stiff, bend the end of the L lever )... of course clean the 2 sw. contact points, reflow the solder. 
3. Jump across the sw. with a test wire (wired tight or gator clips) Now if the unit falls out call it junk.  Otherwise you could solder the wire in and never worry about it doing it again (but you can't lock it in fwd,N, or rev)

I.e. the switch likely needs tweaking on the arm,  nothing more.

Im trying to recall what I had to to one of mine as a kid that would magnetize and stick.  It never lasted long.

It wasn't just ac, I never ran dc. It might have been Neu. full throttle, whistle, and repeat with reversed track leads, no tender..?  It might have gotten a conical spring or pad (or both) added at the land to stop it from striking. I know I saw both, just can't recall which was which upside-down.

did all this stuff you could imagine. another rebuilt E unit doing the same thing so I conclude it is another bad rebuilt E unit it also tells me the Lionel train hobby is a waste of time and more than that a lot of cost to try and keep anything they build running as it should

very sadly enough this is the only loco I have that does this last thing i’ll do is go with the electronic E unit but in the near future will sell all this junk it’s not fun anymore

Rebuilder:

Please don't give up. I love old MPC locomotives myself and the E-units can be a challenge. If you're up to rebuilding the E-unit, drop out the slug and polish it with automotive rubbing compound until it is clean and smooth and reinstall it. The MPC Geep shown below was a basket case when I bought it at a local train show and now runs smoothly and dependably!

If you give up, drop me an email and I'll send you a QSI RU-101 electronic E-unit free of charge. Don't give up on America's greatest hobby!

@rebuilder posted:

very sadly enough this is the only loco I have that does this last thing i’ll do is go with the electronic E unit but in the near future will sell all this junk it’s not fun anymore

Diagnostics and repair can be frustrating to some folk; understandably. We all want the repair to be fast, simple,and cheap. Unfortunately it isn't as cut&dry as folks might imagine at first. Be it your car, or the trains, the variables to each issue can stack up high. Get in a hurry and the next thing you know there is a hole in a wall.

Relax, run another.  Ive left poblems rest for years..One loco down out of how many? How old now?  I've lost one about every 10yrs averaged. But in waves of "oh man, #$&%.

The satisfaction in success; that's fun... sure you don't want to taste that?

( I don't accept "I can't" easy... "Won't"; I don't argue with much.)

I knocked the electronic E a little, but it was really about you jumping the gun. If you've got the deep pocket, go for it..... make sure you don't buy something too light, that's all. If it turns out to be something intermittent maybe you can use it later on another.  I like electro mechanical, you can like electronic or not; help is still here.

Process of elimination... or logic chain; a techs best friend....and a short one so far.

1. you can't  duplicate the  issue ,either direction, while the e-unit is 100% bypassed, motor running.   Points to e-unit. (not a sure thing, just points)

2. bypassed, but mounted e-coil in the circuit. E-Coil dropout cannot be duplicated.      This points to fingers/wires/drum (or bad #1 test, something intermittent in the motor. Too deep, and iffy for "fast" fix, check elsewhere 1st. 

(frame wire...tighten and clean that terminal screw/nut and thread area on frame. Lightly squeeze the wire terminal crimp to reseat connection if there. This is a common issue sometimes missed.

3. continuity checks are needed on wire/drum/finger assembly...result yeilds #4 step.

You haven't even used a meter here yet have you?  That is the next question, do you own a ohm, volt, or multi-meter(even an itty bitty toyish one)  Test light probe?

You kinda need one to check things better. Meters don't have to be expensive for basics. When you're ready for design, then upgrade   You will likely make far more use of one than you can imagine today if you can measure things at all. (you can)

Extra socket , wire, 12v bulb?  (automotive is ok) and a simple power source (lantern battery is easy to use here, 9v?, anything, transformer, wallwart etc.) 

If you hang in there, you'll likely get it. Basics arent so hard. It's not always this tough. Once you have the basics down, everything starts to click.

It can also take a while to firgure out how to word things so different people can relate easily to what we say too. (that's why you get so much "echo" of information in others replies. I had to teach basics to teen assistants, rephrasing a few times always worked.)   If one person is more easily understood, address them more often. Then other folks usually back out of it some; making more general fact statements or catching the loose ends.

 

@rebuilder posted:

hello all, i’ve encountered a strange problem with a 1978 model year lionel SD 18 diesel lionel loco. it runs fine in forward but in reverse will randomly stop and will not cycle the E unit the rollers and track are clean and the other engines of that same design are all good I suspect a failing E unit any input is appreciated

I had a similar issue with my 1977 Southern Crescent Limited steam locomotive a few years back. I had a local train guy repair it and it was only $17! She still runs great 40 years later! There's tons of good train repair guys out there, just gotta find a good trustworthy one.

all good info guys and I did solve the E unit problem. the next adventure now is to replace the plastic knuckle leaf spring type with a die cast knuckle and coil spring i’ve done it before following some good recommendations but this die cast knuckle is a reproduction that seems to not want to fit into the pocket without popping the spring off the rivet any new ideas on doing this?

@TrainLarry posted:

Replace both sets of contacts and the drum.

Here is the proper spreading tool for servicing 'E' units, available from The Train Tender.

Here are 2 nice video tutorials showing the rebuild procedure.

Part 1

Part 2

Larry

Thanks Larry,  Fortunately the engine that has this type of reverse unit seems to work OK.  I'm pretty sure the others have modern digital boards.....