70 Tonner With DCC re-assembly

[Ckrails]

Had a little mishap on the home rails and a derailment caused a short that partially fried the wires on from the trucks to the DCC decoder.  Pulled it apart, wrapped the wires, reassembled the chassis and ran juice from the trucks directly to the motor (so far, so good).  Looked at the wires and the decoder and only then realized I'd forgotten to make note of which wire went where on the decoder.  Unfortunately the instructions don't make a note of it either.  Using the left side as a basis, I currently have red wires from the trucks and a black wire to the decoder - is that correct or should there be only red (or only black) on that side?

Also, is there any visual way to determine if the decoder is fried?

Thanks!

[Len]

The standard decoder wire colors are:

RED from right-hand rail power pick-up to decoder
BLACK from left-hand rail power pick-up to decoder
ORANGE to motor brush (+) connected to right-hand rail before decoder install
GRAY to motor brush (-) connected to left-hand rail before decoder install
WHITE front headlight(s) power sink
YELLOW rear headlight(s) power sink
BLUE common (+) headlight(s)/function(s) power source

If there are also VIOLET and GREEN wires, they are for additional function outputs from the decoder.

Len

[Ckrails]

Thanks for your reply, Len.  The decoder that came with this model is the PCB, which controls only lights, direction and speed.  Each truck and the motor have a black and a red wire.  Another way of putting it is should all the wires on each side of the decoder be the same color?  If that is the case then when I started to reassemble it I reversed both trucks with respect to the chassis, or when it was manufactured the motor wires were crossed under the board.

If the decoder is burned out I don't plan on replacing it right away, so when I reassemble it with this one I want to make sure I don't burn it out (assuming I didn't already).  I read on another thread that these boards do burn out pretty easily.

Thanks!

[Len]

Unless you see something turned black or brown that should be, or a hole blown in an IC chip, there's no good way to tell visually if a decoder is fried or not.

Using the front of the loco as a reference, the red wires from the trucks would be on the right, the black on the left. For operating on DC, without including the lights, the red wires would go the the motor red wire, the black to the black.

For installing a different decoder, the red truck wires would go the the red decoder wire, the black truck wires to the black decoder wire.

The red motor wire goes to the orange decoder wire, the black motor wire goes to the grey decoder wire.

Detailed instructions for installing a different decoder in this loco, including the light circuits, can be found at:
http://www.tcsdcc.com/Customer_Content/Installation_Pictures/HO_Scale/Bachmann/Spectrum_GE70/Bachmman_Spectrum_GE_70.html

The instructions would apply to any manufacturers decoder you installed. Personally, I prefer heat shrink tubing to insulate the wire-to-wire connections. Thin electrical tape works to hold the wires in place if you can't lay hands on Kapton tape.

Len