Testing e-unit

It is not clear if you have a 2 way FRFR e-unit or a 4 way FNRN e-unit. 

Cheaper eunits are FRFR or a 2 way e-unit and usually have a pendalum that swings between F or R sides no neutral. 

Better Lionel engines have a FNRNF or 4 way e-uint which has a plastic drum that stops each quarter turn and has several wipers on the drum.  It gives a neutral between each F and R.

Tell us what locomotive the e-unit came from.  After all that cleaning maybe you could just reinstall the e-unit and test it by putting a transformer wire to ground and the other to the pick up, hold the engine up right and turn it on and off and watch the wheels.

Charlie

Very useful.  I've done a similar test but went about it slightly differently.  There are really two separate functions to be tested.  One is that the solenoid cycles each time power is applied and the drum rotates.  The other is that the switch contacts make good connections.  Having applied power and gotten consistent drum rotation I would then hook up my ohmmeter across the contacts (as your lightbulb) and cycle the solenoid/drum by hand.  Separate testing of the oposite contacts would then assure me that the E-unit had correct continuity in all positions.  Filmed it here:  

This e unit is out of a 250E. It is an early version of the now standard three position e-unit. It is FNRN, twice per revolution I think. I use to check the contacts with a meter, but this method was very fast and can check contacts many times quickly. 

To David Johnson, find your method interesting, to test my e units I use a spare motor and install e unit in a jig to test, if motor works both way the e unit works. That being said I would appreciate a line drawing on what you did. Thanks.

Here is a drawing on how I test an e-unit with a single lamp. The AC is applied momentarily just to get the solenoid to sequence the drum.

Thank you for the information, much appreciated. I learn so much from forum members like you.

February 2005 of O Gauge Railroading had a more elaborate version of the same thing, with a stand to hold the E-unit and a built in light bulb and connecting wires with alligator clips.  As I recall it was powered with a 1033 transformer which you supplied but it could be just as easily updated with a wall wart and perhaps red/green leds to indicate the two opposite forward and reverse connections (though all you really need to know is continuity - indicated by a lit bulb.  PM me for a copy if your interested.

Curiously I had one not long ago that was a bad ground.  The unit is grounded to the motor in many cases by a single attaching screw located on the lower e-unit frame.  The solenoid is grounded to the upper e-unit frame and the problem was corrosion where the two frame halves were staked together.

I wish I understood electricity like you guys.

I learned to rebuild e Units due to the high cost of sending them out. The problem in doing such is when the lever is loose and you have to unsoder the coil and redue the lever assembly.. the wire is thin and if you break of the wire you have a real problem, the new coils are easy to do as you can unwrap a section of wire and  continue, the problem is with old coils which are wrapped with paper and you have to strip of the paper to get access to the coil. as soon as I resoder the wires to the unit I test the solonoid  to see if it operates. then and only then do I continue to finish with new fingers and roller. during assembly I wrap a rubber band around the assembly as that when i spread the plates there is a force inward this prevents the fingers or roller from falling out of position even though i use a e unit vise .It takes me about 15 min to rebuild a e unit and I like to do several at a time.. I purchase the fingers and rollers from The train tender who always gives me good quality parts. I like to do my own sodering wires to the fingers then run a electrical continuity test from the finger to the stripped wire to make sure it works and the soder does not flow in to a adjacent finger. 

DougB posted:

... I purchase the fingers and rollers from The train tender who always gives me good quality parts. ...

Jeff at Train Tender is a good guy.  I like dealing with him as well!