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hello!
I've been having some trouble with some Decoder installations. A friend of mine asked me to try and fix his Blue-line Pennsy M1A 4-8-2. I've found that whenever the drivers touch the rail, the locomotive either buzzes and hums, or it runs forward out of control.
I also just had the same problem with a power truck i just bought for my Arrow III EMU. the Arrow's power truck ran fine on DC just the other day, and i only installed the decoder an hour ago. However, i've still yet to find what caused this problem in the M1 (and i have been tinkering with it for weeks). Does anyone know what kind of problem this is?
It goes full speed ahead when the direction is set to forward, and it hums when in reverse, and the motor controls do not respond. The original decoder in the M1 seems to be burnt out, but after placing several other working decoders into the M1, it seems clear that there is a problem in the locomotive as well.
Any hints? whatever it is, its not in the decoder as far as i can tell.
Modeling New Jersey Under the Wire 1978-1979.
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Posts: 2,271
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This is a fairly uneducated guess, but "buzzes and hums" and "runs forward out of control" sounds as if the power is bypassing the decoder somehow, since this behaviour can be characteristic of DC locos (trying to) operate on DCC.
Perhaps the motor is not fully isolated from the frame or other "current-carrying" components? I know in some cases, pickups are actually part of the motor brushes, and can be extremely hard to isolate, or even see...
Time to get out the multi-meter and look for conductivity where there should be none...!
Hope that helps.
Andrew
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Yeah, this is a tough one. I got the power truck on the Arrow III fixed "good enough", so that it runs, although there is still a slight humming that concerns me. I took it apart, and all the wiring was straight forward, it did not seem like there is somewhere for there to be a short. the truck is literally a motor with wheels attached to it in a nice case, and the contacts were specifically made so that DCC would be an easy install. When it runs, it runs as good as any athearn blue box kit, but when its sitting there it still makes noises.
I still have not been able to solve this problem on my friend's M1A. the wiring on that thing is way to intimidating, and i only got it to work for a short time, so there is probably something loose in there that i can't find. I just don't want to tear that thing down into its individual pieces.
Modeling New Jersey Under the Wire 1978-1979.
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If the M1a is new, send it back to Broadway. The engine is advertised as DCC ready, so it should not be giving you this problem. If you mess with it too much, they may say you've voided the warranty... Quit while you are ahead on this one!
Yes, power trucks can be a problem. I have a Lambert Brass railbus that has the wheel wipers/power pickups integrated with the motor brushes, and it's almost impossible to isolate the motor because of the miniscule distance between the wheel and the motor.
Andrew
Posts: 1,992
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Joined: Dec 2008
MasonJar Wrote:If the M1a is new, send it back to Broadway. The engine is advertised as DCC ready, so it should not be giving you this problem. If you mess with it too much, they may say you've voided the warranty... Quit while you are ahead on this one!
Yes, power trucks can be a problem. I have a Lambert Brass railbus that has the wheel wipers/power pickups integrated with the motor brushes, and it's almost impossible to isolate the motor because of the miniscule distance between the wheel and the motor.
Andrew
The M1A already came with a pair of wires disconnected in the tender that my friend tried to solder together, not really knowing where they go, so i'm going to say that the warranty is already voided. I'll still tell him to try and send it back, i didn't do any surgery on the model.
As for the power truck, the wipers and motor are on two different assemblies, so they are very much seperated. The only way into the motor assembly is through the pair of wires that you can easily disconnect from the wipers, so i have that straightened out as far as i can tell, but i'm still worried about the humming noises.
Modeling New Jersey Under the Wire 1978-1979.
