Latest version Bmann 4-8-4 NW Class J Motor and disassembly issue

kmcsjr Apr 27, 2017

  1. kmcsjr

    kmcsjr TrainBoard Member

    I took out my NW Class J 2006 version - 3 pole CAN , DCC board. Etc. Prepping it for DCC install. Just running it around. It stalled. It wouldn't move period.
    I took off the shell, checked for continuity - no problem. Voltage directly to the motor leads, still no movement.

    took it apart (yikes, I'm gonna be quartering...)

    I removed the motor. Applied voltage to the leads... Nothing.
    I spun the shaft a few times. Voila!, motor runs. But stalls. the only way to get it moving again, is to spin the shaft, then it responds. I've been trying it, for hours and i get it spinning, drop the voltage and the next time i apply voltage, it won't move. would a short in the coated wires have burned up the motor, or is this a simple failure?

    SOLUTION - order a motor. Right?

    Here are the questions
    1) How do I remove the cylinder assy, from the frame, without breaking it? I don't HAVE too, but since I snapped off the cosmetic shock support, trying, if I want to dig out the plastic bit and replace it , I need to. I think it is glued in and since I see no way to remove the rivet that attaches the cylinder assy, to the drive wheel, I don't want to snao it off ruin and have no way to install a new one.

    2) I think I'm going to forgo the PCB connector ( I will use it to get Chassis voltage to the tender, but will wire the light and motor directly. I can't find a short, but why did the motor fail?

    3) Has anyone had the coating fail, on bachmann steamers, where they painted the wires black and the black flakes off, but apparently not the plastic coating?
  2. woodone

    woodone TrainBoard Member

    I too have a Bachmann J class. I was to install a sound decoder into it. OK all went well until I noticed that only one side of the loco was picking up power from the rails. ( The left on this one) I removed the boiler shell and found that there is a small PC board at the rear. There are two screws that hold the board down to the frame. These crews make contact with the board and the frame. My screws were loose and not making good connection. So I tighten them up- Good! now he power is going to the loco. Test on a test track and NO movement?? So I jumper the motor conections and hit the power. The motor will not run. So now I have to remove the motor. Quite the chore!! The cylinders did have to come off but these are only held with a screw. Maybe the paint they use is holding the cylinders in place on your unit? Try prying a bit to loosen. The next problem I had was the removeal of the side rod and valve parts. They are held in the frame into a slot or hole. Mine were painted and I had to put on some goof off to remove paint so I could pry the parts off. Be careful. Does not take to much to break these. There is no reason that you should need to re quarter has the wheels and side rods and valve gear will com off in one chunk. Watch the eccentric on the driver, you can pull the valve rod off the very small rivet on the eccentric. If need be pull the eccentric off the driver so you wil not be fighting it. I found that the motor in mine had a dead spot in the windings- So I installed a new motor, From Bachmann they were only ablut $15.00.
    Have fun-- these are a real chore to get back together!
    kmcsjr likes this.
  3. kmcsjr

    kmcsjr TrainBoard Member

    I think we ultimately have the same root problem. The motor. I ordered one. The little board is terrible. I will bypass as much as I can. I will use it for chassis pickup to the tender, but will jumper motor and light. I pried the shock absorber and it snapped. Hopefully I can take a pin vice and drill it out. I ordered a replacement. I'll try goof off, if I need to remove the cylinder. I got the motor out, leaving it in. Fingers crossed. I don't like that we both had bad motors. But maybe the new ones will last!

    Sent from my iPhone using Tapatalk
  4. RGW1

    RGW1 TrainBoard Member

    I have had the black (varnish ) coating flack off of 2 Js .One I got used and it would not run because of short in the tender to engine wires. The other one had flacking coating and it stopped running one day ,so I ran my own wires between the PCB in the engine and the pin conector in the tender. What a job of soldering these . ( I burned out the engine LED, wrong connection OOPS ) The engine ran good for a while than quit . Finally figured out the problem. I had a short with the metal boiler shell. when I removed it worked for a while ,but would move with handling . Bachmann has electrical tape inside on the frame halves but this can move. I added tape paint and solved the problem. My son has another J and has had NO problems. Maybe this can help somebody.
    kmcsjr likes this.
  5. Burlington Northern Fan

    Burlington Northern Fan TrainBoard Supporter

    I believe if you send it to Bachmann they will fix it for you. I think if warranty, for free? Just a thought, somethings are worth your sanity, admit defeat early and send it in. It helps....:)

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