Bachmann USRA Lt 2-8-2 question.

RGW1 Aug 24, 2021

  1. RGW1

    RGW1 TrainBoard Member

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    I just got a non running Bachmann USRA Lt 2-8-2 DCC / sound off the Bay. Found a broken wire in the tender and repaired it (pinched in the center mounting screw ) and tried it out on my DC only layout and it only hummed and no lights or sound

    In the past I thought all Bachmann DCC was dual mode so would run on DC. I opened the engine and tested the motor and it works. So my question is does this engine only run on DCC or has the decoder puked?

    There may be a gear bind , but I have not tested it yet , also one wire was off the motor ,but I think I did this in removing the motor.
    I use to run power test leads to the plug on the engine but if you send track power to the LEDs they seem to not like it LOL. so now I run test leads to motor brush tabs.
    thanks
     
  2. Mike VE2TRV

    Mike VE2TRV TrainBoard Member

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    Try alternating between forward and reverse polarity, and watch for any movement in the motor.

    Or try to turn the motor shaft manually, unpowered, to see if there's any resistance in the mechanism. There's nothing like a finger to feel that out. You could also test the mechanism in the same way if you have the motor out. Whichever jams is the culprit.

    If it's the motor, you might try "rescuing" it by thoroughly cleaning it out with electronic contact cleaner (the "tuner cleaner" of yore) and re-lubing it. I did that with my '73 Model Power sharknose a few years ago and it's been running merrily ever since. It's also the technique I use to clean and overhaul the motors on the fans in my home. Some of them are over 20 years old!

    HTH.
     
  3. RGW1

    RGW1 TrainBoard Member

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    Motor and gears are fine. I beleave it is a DCC issue. I should be able to get it running with some modifications.
     
  4. fordy744

    fordy744 TrainBoard Member

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    most decoders are dual mode capable but the DC running capability can be turned off. this can be done in DCC programming, not sure how to remove this outside of DCC, unless you can provoke a factory reset in DC?

    DC locos hum when run on DCC but not normally the other way round. A motor will hum if it gets power but can't turn, this could be drivetrain or external linkages.

    try running with the motor removed from driveline but wired to factory wiring.
     
  5. RGW1

    RGW1 TrainBoard Member

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    thanks .The gears are free and the motor works .I will fix the motor wire and test it out. I can check the wiring colors and just send power to the motor pins. Have to be careful if power is connected to a LED head light by accident they burn out.. Guess how I know?
     
  6. Mike VE2TRV

    Mike VE2TRV TrainBoard Member

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    LEDs are not fond of being reverse-polarized. Most tend to burn out around 6 volts reverse voltage. They also are quite fragile when powered with forward DC voltage higher than 1.5 to 2 volts without a resistor in series to limit the current.

    Plenty of "oops" moments here too. :whistle:
     
  7. fordy744

    fordy744 TrainBoard Member

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    indeed, been there and done it too many times...
     

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