DCC and Santa Fe take 2

[bigbear62040]

I got a Santa Fe Flyer set a few years ago and I want to convert it to DCC. Is this possible? I took the housing off and it only has two wires. I want to use it on my layout but I don't want engine meltdown that DC tends to do on DCC. This is the set I have. This may be the second time I posted this, if so, I apologize.

[Tylerf]

Is there a full 4 axel drive or is it just a small motor over one set of wheels? And can you tell us where the wires go.

[bigbear62040]

Here is a pic of it's guts. Looks like a 4 axel system.

[bigbear62040]

How would I hook a decoder up to this.

[Tylerf]

Ok it appears pretty typical of an install. First make sure everything is insulated so especially the bachmann locos tend to use the through frame style to get power to the motor and lights. If it is like this than you should probably figure out a way to stop that contact at the trucks and hard wire them. After isolating the decoder instructions show the color codes for what goes where. Connect the same side power wires together and to the decoder. Next take the motor wires and hook them up to there colors and finally hook up the light wires accordingly. It's really not that hard just isolate everything to be super safe from decoder recking shorts. A decoder can easily be blown with a simple wrong connection. So be CAREFULL I say this from personal expirience. The isolating is the only real hard part.

[Jim Banner]

From examining your photograph, I am seeing and guessing the following:
(1) I am guessing we are looking at the top side of the locomotive.
(2) At the extreme left I see a red wire with one end under a screw.  I guess that the other end goes to a headlight bulb, which I guess is the black spot I see directly above the screw.
(3) I see a black headlight wire crossing over the motor and connecting to the brass coloured brush holder at the right hand end of the motor.
(4) I also see two wires coming up the right side of the frame
and going to the visible brush holder.  I guess that these two wires come from the right hand wheel pickups.
(5) If all of the above are correct, then we can deduce the following:
(6) There is another motor brush holder under the motor.
(7) The frame connects to the left hand wheels.
[8] the unseen brush holder connects to the frame.

To install a decoder, you need to do the following:
(9) Electrically isolate the motor from the frame.  I believe this will require removing the motor, probably by removing four screws, two at each end of the motor and lifting it out.  Do not force it out or you may bend the drive shafts and universal couplings at each end of the motor.
(10)  I am guessing you will find a tab on the hidden brush holder and that the tab normally contacts the locomotive frame.  Solder the end of the grey decoder wire to this tab.  Then insulate the bare end of the wire and the tab from the frame with electrical tape.  If the bare end of the wire and/or the tab can touch the metal shell of the motor, insulate them from that too.  You may have to grind away a bit of the frame below the tab to make room for the wire, the solder joint, and the tape.  Do not remove anything from the motor.
(11) Replace the motor, making sure the drive shafts and couplings slip back into place.  Do not force them.
(12) Clip the wires off the top brush holder (the one visible in the photo.)
(13) Use an ohmmeter to check continuity from the brush holder to the frame of the locomotive.  There must be no conductance between the brush holder and the frame (that is, the resistance should be infinite.)  If there is any conductance, the motor is not properly isolated - remove it again, find out why, and correct the problem.
(14) When the motor is known to be properly isolated, then and only then solder the orange decoder lead to the visible motor tab.
(15) Remember those wires we looked at in (4)?  Solder both of them to the red decoder wire and insulate the joint.
(16) Strip the end of the black decoder wire and put it under the screw we looked at in (2).
(17) Connect the black headlight wire to the white decoder wire and insulate the joint.
(18) Test run the locomotive.
(19) Reassemble the locomotive.
(20) ENJOY.