"While it is possible to bypass a functioning e-unit without removing those two wires, by rotating the e-unit drum to one of its neutral positions, you don't know yet whether your e-unit is functional. Later, when you reconnect those wires, it doesn't matter which goes where."
Bob Nelson
Hi Chris,
I would recommend disconnecting the E-unit, to test the motor by itself. We need to determine if the problem is in the motor, or E-unit. If the motor runs after bypassing, then the E-unit is bad. If it doesn't run, we need to find out what is wrong in the motor. You can mark, and label each wire you remove, and make a drawing to show where it goes. Maybe put a piece of tape on each wire you remove with a number or letter marking.
This is a necessary step. Do you have a soldering iron?
Paul
And...
you can remove wires at the terminal at the side of the E-unit. But do not remove the wires coming from the fingers at the fingers. Instead, remove them from the brush end. One wire from the fingers will go to the field coil. You will need to cut this someplace with enough wire to splice onto for your test, and to reconnect later. Leave enough wire to work with.
There is a terminal on the e-unit's wiring board that connects together the pickup, the e-unit coil, and some of the e-unit fingers. If, in addition to disconnecting the brushes, you disconnect the e-unit fingers from that terminal, you do not have to cut (or otherwise open-circuit) the wire between the fingers and the field coil.
However, there is almost no chance that the e-unit could have failed in a way that would make removing that third wire or cutting the field wire necessary. I would first try to run the motor with just the brushes disconnected and rewired in series.
There is, of course, no harm in marking the brush wires when you disconnect them from the brushes, but no need to do that either. (In its normal operation, the e-unit itself swaps those two wires every two steps of its drum.)
Thanks, Bob.
looking at the circuit diagram, I can see that it could be done that way as well. There is usually more than one way to accomplish a task.
Chris,
whichever approach you choose is up to you, and your comfort level.
Do you have a soldering iron ?
You know, the more I think about this, I feel that the goal is to help someone new in the hobby. I think there are a lot of shortcuts we all learn as we become more comfortable with these circuits. That will come in time. I feel it would be better to advise a newcomer to wire the motor EXACTLY as pictured in the first diagram, to avoid any confusion.
Here we go...
https://www.flickr.com/photos/105547860@N03/31791088700/in/dateposted/
So I THINK I wired it the way you suggested Paul:
https://www.flickr.com/photos/105547860@N03/31356274243/in/dateposted/
I think one end of the field coil is attached up through the top (one end of the white wire), and the other comes out the back (I wrapped it around a hole in the frame). I also attached the black wire coming up from underneath (the track contact, I hope) to one of the brushes. Still no go.
https://www.flickr.com/photos/105547860@N03/32048257271/in/dateposted/
Good thing there's a big train show coming up in Springfield...
The place on the field where you attached the white wire (from the brushplate) is usually mechanically grounded. Try disconnecting the white wire from that location, and attach it to the field wire you wrapped around the the hole. (remove the wire from the hole first)
Good catch ! I think you are correct.
Hope it is going well. I am tinkering today, too.
I looked at your video again. You have motor buzzing noise, good sign. Hopefully connecting the white wire to the field coil wire , the one that is currently through the hole in the frame, will complete the circuit.
I apologize. I probably did not make it clear enough in my verbal instructions to bypass. You need to connect your white wire from the brush to the field coil wire that used to go to the E-unit. The other end of the field coil is ALREADY attached to frame ground.
Thanks to cwburfle and his sharp eyes for spotting that.
paul
The motor does not appear to want to go. I still get the buzzing.
For giggles, I checked the continuity of the wires I used to jump the connections. The Jump wire was fine and my connections at the brushes was fine, but when I moved the probe further up the connection to either the wire coming from the field coil or wire coming from the pick-up plate, I could not get continuity.
What this means, I do not know.
C
I'm not sure I understand where you probed; but remember that the field winding is insulated with lacquer. Usually, only enough of the ends of the coil wire have the lacquer scraped off so that connections can be made.
Can you send a picture of how you have it wired now ? And check these points for continuity:
1. Pickup shoe to brush it is wired to
2. Brush to brush
3. The second brush(the one wired to field coil) to frame
4. The end of the field coil wire to frame
and when I say "brush", I mean just the terminal the wire is hooked to
The buzzing is the motor is halfway working. Maybe the field coil is energized, but not the armature, or vice versa.
you do say it turns easily by hand ?
Never panic ! I have this a couple of times reviving old trains, and it started with buzzing. Both are running happily now.
One last thought:
put it on the track and give it a push !
Yes, I'm serious. Sometimes these trains have not run in so long, they want to roll over, and go back to sleep. I was remembering the last time I had this problem.
I bought a 1688e at an antique store. The E-unit had bent and mangled fingers. I bypassed the E-unit, the way you are doing. (the field and armature are in reversed position in that circuit). I cleaned the brushes, and commutator. Put it on the track, and
buzzz
no love.
Gave it a nudge, and it twitched a little. Kept after it, and ,bit by bit, it awakened from it's slumber !
Today that engine has new brushes, a rebuilt E-unit, and I have to be real careful not to launch it off the curves.
I still think we are close to getting your train going !
Postwar Paul Can you send a picture of how you have it wired now ? And check these points for continuity: 1. Pickup shoe to brush it is wired to 2. Brush to brush 3. The second brush(the one wired to field coil) to frame 4. The end of the field coil wire to frame Paul and when I say "brush", I mean just the terminal the wire is hooked to
My E-unit is out I not connected, so here goes as close as I can:
1) Have have two pick-up shoes, one fore & one aft. I checked for continuity from each of these to the wire that comes up from the bottom of the train. I get sketchy continuity from the front one (goes from 000 to 1000 making stops all over the place), and no continuity from the rear shoe.
2) Brush to brush is good.
3) Field coil brush to frame is good.
4) Field coil wire (the part with no coating) to frame is good.
For what it's worth, I checked for continuity in the wires and attachment points on the e-Unit and got nothing.
I gave it a push or four, but it still didn't want to budge.
What is the resistance of the field coil?What is the resistance of the armature?
It may well be the pick up wire.
O.k. So, take two wires from your transformer posts(one from each post). Set your transformer about halfway, touch one wire to the brush you have connected to the pick up shoes. Touch the other to the frame. Any signs of life ?
You should have lift off.
If that works, it would indicate a problem coming up from the pick up shoe.
oh, and maybe set it up on a couple of blocks, so the wheels are up in the air, and not touching anything
a.k.a. The "Hotwire Test"
I am looking at my 2026. It's hard to see in there, but there may be something with the way those shoes mechanically touch to transmit the current . It looks like they are touching a leaf spring. If the wire is attached to the spring... we may have a cheesy connection. Let's see how the "Hotwire" test goes.
Hello Chris,
thinking about the problem with your 2026. Been running mine today, it helps me think. I am hearing very clearly in your posts that you are not getting continuity from the pick up shoes. You have mentioned this twice. This is a problem that will need to be addressed to run this train on the track. The bigger issue is : does the motor run ?
So, if you can " Hotwire " it, as I mentioned previously. This should produce results, the motor running. If it does not, we have something above and beyond a normal repair.
It could be something like cwburfle was inquiring about, the resistance readings on the field , and armature. He may be able to help with what the expected readings SHOULD be.
Or, it could be something like side rod binding. The 2026 is an extremely free rolling engine. You should be able to spin the drivers with very little effort.
But, so far we have been testing it on the track, and we don't have good continuity from the pick up shoes.
I am hoping that is all it is.
cwburfle I think you need to perform the most basic test. Disconnect the wires from the e-unit (reversing switch) to the brushes and field. Attach a jumper wire between one brush holder and the field. Attach test leads to the other brush holder and the chassis. Does the motor run?
I think you need to perform the most basic test. Disconnect the wires from the e-unit (reversing switch) to the brushes and field. Attach a jumper wire between one brush holder and the field. Attach test leads to the other brush holder and the chassis. Does the motor run?
A week ago I recommended that the original poster perform a basic test on his motor, bypassing everything. I see no indication that the test was done.
Just my 2 cents, but I feel potential mechanical issues have been overlooked. Can he even spin the weels by hand. He did take the wheels off, and re-pressing and proper quartering is questionable. Remove all side rods and see if you can spin the mechanism by hand.
Yes, essentially this is the same test.
as what?
I would delete this post if there were a way to do that.
cwburfle What is the resistance of the field coil?What is the resistance of the armature?
With the Ohms set at 200, one probe on the end of the field coil and the other on the body, I get 1.8.
There was no continuity from any of the 3 plates the brushes contact to the shaft of the armature. The resistance between any two segments of the armature plates is 1.6 (Ohms set at 200).
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