# Athearn Blue Box running “backwards”



## ecmdrw5 (Jan 16, 2021)

I picked up a used Athearn Blue Box GP38-2(DC). I cleaned up the wheels, put it on the track, and it runs “backwards”, short hood at the back. I did some searching and people are saying to reverse the trucks. 

I guess I don’t understand how that works. The tabs that the wires are soldered to can only fit one way in the window in the frame. What am I missing?










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## Lemonhawk (Sep 24, 2013)

Looks like some one has done some rewiring on your unit to improve the track contacts. You would need to unsolder the wires to the tabs on the trucks (that L bracket like thing) then swap the trucks and solder the wires to the tabs. Its also possible that there is another wire to each truck to enable 8 wheel pickup, can't see that in the picks. Another possibility is to just swap the wires to motor brushes, I can't see in the pictures what was done their.


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## ecmdrw5 (Jan 16, 2021)

Lemonhawk said:


> Looks like some one has done some rewiring on your unit to improve the track contacts. You would need to unsolder the wires to the tabs on the trucks (that L bracket like thing) then swap the trucks and solder the wires to the tabs. Its also possible that there is another wire to each truck to enable 8 wheel pickup, can't see that in the picks. Another possibility is to just swap the wires to motor brushes, I can't see in the pictures what was done their.


All they did was replace the top metal bar with wires from what I was told. Swapping the trucks would put the tab on the fireman side which would fix the issue. The way the frame is made the window for the L tab only allows for the tab to be on the engineer’s side. 

I’m guessing he had the motor apart at one time and switched something up. I might just upgrade the wiring to get it ready for DCC and swap the direction that way.


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## DonR (Oct 18, 2012)

The easiest way to correct the loco's direction is to flip the
2 motor wires. Normally, for a loco 'facing' left the red wires
from the 2 trucks should be from RIGHT RAIL wheels, and
the 2 blacks from LEFT RAIL wheels.

When you upgrade to DCC there is a decoder CV that can be
set to change the reaction to the FWD/REV controller button.
This makes possible two locos, for example F7 A units, to run back to back
in a consist...the rear unit 'thinks' FWD is REV.

Don


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## PatW (9 mo ago)

ecmdrw5 said:


> I picked up a used Athearn Blue Box GP38-2(DC). I cleaned up the wheels, put it on the track, and it runs “backwards”, short hood at the back. I did some searching and people are saying to reverse the trucks.
> 
> I guess I don’t understand how that works. The tabs that the wires are soldered to can only fit one way in the window in the frame. What am I missing?
> 
> ...


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## MidwestMikeGT (Jan 4, 2021)

This is a DC machine, correct? Ummmmm....how about just flipping the locomotive to face the other way?


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## ecmdrw5 (Jan 16, 2021)

Yeah. Thanks for the replies guys. I’ve fixed the issue since then. I took it to my local shop and he said “the motor was backwards”, which I’m assuming meant upside down. He actually took it apart for me and fixed it over a few days. 

He said he’s done that in the past to not have all the locos facing the same direction in a consist.


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## DonR (Oct 18, 2012)

Your local shop said the 'motor was backwards'...he should
have said the 'motor was WIRED backwards'. All he had
to do was flip the two wires to the motor...apparently the
previous owner had made the change, possibly in error.

With the loco facing FWD the right wheels should have
a red wire, the left wheels a black wire. The red wire
should be connected to the a motor tab so that when
the power pack is set FWD the loco will move FWD.
If it goes REV then flip the motor wires as your shop
did.

Don


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## DanRaitz (Jun 24, 2021)

When he said that your "motor was backwards" what had happened was that at one time somebody had the motor apart and then reassembled it with the magnets in the wrong position. In the Athearn Blue-Box motors one of the magnets has one end painted white and that one is the "top" magnet with the white end towards the brushes.

Dan


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## DanRaitz (Jun 24, 2021)

DonR said:


> The easiest way to correct the loco's direction is to flip the
> 2 motor wires. Normally, for a loco 'facing' left the red wires
> from the 2 trucks should be from RIGHT RAIL wheels, and
> the 2 blacks from LEFT RAIL wheels.
> ...


In an Athearn Blue-Box there aren't two motor wires. In its stock configuration the BB motor picks up from the right rail via top motor/truck clip and from the left rail via prongs on the bottom of motor to the chassis.

Dan


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## Old_Hobo (Feb 20, 2014)

That is correct….no wires, just that metal strap to carry power….


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