E-unit problem

Does the eunit buzz????   If not maybe locked in neutral...

Marty

it does buzz.  how could it be locked in neutral? 

You could have an issue within the e-unit itself.

Sometimes the contact fingers do not make proper contact with the drum. This could be due to dirt, or bent fingers.

I had a few replacement e-unit drums that had a very thin film on the metal segments that were preventing electrical contact.

Did the locomotive work properly before you rewired it? If so, recheck your wiring. Here is a wiring diagram for your loco. If the loco did not work before, check the e-unit contact 'fingers' to make sure they are making good contact with the drum. Clean the contacts and drum with alcohol or naphtha (lighter fluid). Make sure the contacts are not bent, broken or burned through, and that the drum is in good shape also. If the wiring checks out, and the e-unit looks good and cycles, you may have a motor issue. To check the motor, disconnect all wires from the e-unit to it, hook one transformer wire to one brush terminal, and the other transformer wire to one field terminal. Jumper the remaining field wire to the other brush terminal and turn on the power. The motor should run. The motor must run like this. If it does not, you have a motor issue. If it runs, but not when connected to the e-unit, the e-unit is at fault.

Larry

i know that the fingers in the e_unit are new as i put them in my self.  i did clean the drum also.  and i do know that the motor does work.  the e_unit does cycle but it does not  shift out of neutral.  i will check the drum to see if i need to clean it more.  

TrainDork, have patience. If all the possible problems are not the problem then a non-possible problem must be the problem.

Go back to start. The first wire on the 4 finger set of contacts goes with the contact on the E-unit coil that is connected to the center rail power. The LAST contact goes to the connection to the field winding of the motor. The two contacts in the middle of the 4 finger set are connected together and go to one of the motor brushes, either one. The two contacts on the two contact set on the bottom are also connected together and connect to the other motor brush. Now; if the e-unit is good, as you said, and if the motor is good, as you said, and it is wired as listed above it should run! If it does not run one of the three is BAD.

To find out which disconnect the three wires from the e-unit that go the the brushes and the motor field. Connect a wire from the motor field to one of the brushes. Connect the other brush to the transformer. Connect the frame of the engine to the other side of the transformer. Note the frame is where the other side of the field is connected, you may or may not be able to see this connection. Connected this way the motor should run. If it does not it needs to be repaired! If it runs then either you still are not connecting the e-unit properly or the e-unit is bad.

It is possible to put new parts in an e-unit and still not have it work properly. The plunger must move up and down, the paw on the plunger must engage the drum AND turn it, all the finger contacts on both sets of fingers must contact the drum. Did you put the drum in backwards? It is possible. As a test, connect the two center sets of fingers, bottom and back, together. Connect power to one end of the 4 finger set and connect a light bulb to the other end of the 4 finger set. When you cycle the e-unit the drum should turn and the light should go on and off with each cycle.

If all this checks out OK and the engine still does not run then something else is bad. Not much left except the center rail pickup roller.

Al

You may want to examine the E-unit, and make certain the fingers are making contact with the copper segments on the drum.

I purchased some 2-contact finger assemblies that have fingers that are too long.

In order to use them, the curved (contact) portion has to be redone to move them closer to the board.

I've only run into this with one batch, but there must be others out there.