Bryan B.
The one wire that comes from the motor should be the Motor - wire. Since the LokSound Select Direct does not have that clip that was the Motor + connection on the Athearn board, you'll have to remove the top motor clip, being very careful to not let the spring that is under it fly away, and solder a wire to it for the LokSound's Motor + connection.
You must remove the brush clip from the motor to solder the wire to it, or you're likely to melt the plastic pieces on the end of the motor. You'll then need to use double-sided white foam tape to fasten the decoder to the top of the motor.
Be very careful that no part of the decoder touches metal anywhere on the motor. The white foam tape will act as an insulator.
You are going to need to solder a wire to the copper strip on top of the motor to gain the other motor wire input you need to attach it to the decoder terminals.
Remove the clip from the motor (watch the brush spring doesn't fly out) to solder the wire, else you may risk melting the plastic end case on the motor.
As for which one is positive and which one is negative, the process usually takes longer to figure out than just soldering the two wires and trying it. If it runs backwards, just reverse the two wires.
I usually mount the decoder board to the top of the motor with some double-sided foam tape.
(Edit) - I was apparently typing Cacole's response verbatim while he was posting ! ;)
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Here's a little trick with Athearn (assuming they are put together correctly to run on DC per NMRA standards of right rail positive = forward). And this should also work with more modern RTR where the bottom of the motor is (supposedly - always check) insulated from the frame and has a wire attached.
Set the loco on the rails. Look at the clip coming up from the trucks - if it is on the fireman's (left) side, the wire on the bottom is the + decoder wire, because the right side pickups in that case transfer through the truck bolsters to the loco frame, which in Blue Box locos would be the bottom motor brush. On Blue Box locos, they had a long metal clip between the truck clips, which came all the way up and were L shapes, and the top motor contact. So if those clips are on the left for the loco facing foward (as if you were sitting in the cab), that side of the circuit is the negative side. If those clips are on the right side, then the top brush is the positive side.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
It's OK, there are two clips. Once is attached to the circuit board and will just pull off witht he whole board, the other is what holds the motor together - don't remove that one, or be very carful if you do so you don't lose the brush and brush spring. Still they try to make them as close to simple and cheap as they used to be. Notice your track inputs to the factory board - one side only has a single wire, not one for each truck, and it folds under the circuit board and is held captive by the screw, at least for those where the circuit board is attached to the frame with screws, like the RS-3. The frame is still the 'wire' for one side of the circuit, even though the motor is now isolated from it.
No need to change the motor leads. Just change CV 29.
The athearn bulbs are 1.5 volts and definmitely need resistors. Or better, replacement with LEDs, as they are ugly and have short lives. Select Direct already has current limiting for LEDs, which wouldn't be correct for the Athearn bulbs. Just press the bulbs out (usually tacked in with white glue), and get yourself some lenses from MV Products to fill the holes, and place and LED or two small ones behind the lenses, depending on the style of light. In the long run it will be much better.
If you connected the bulbs straight to the light terminals, chances are pretty good you burned them out. The Select Direct board puts out around 3 volts at 8 to 10 milli-amps. While the current is in the right range, the voltage is double than what the Athearn bulbs require.
You need (should have added) a 150 ohm resistor to each of the bulb leads.
Check each bulb with a AA battery and see if it lights. I have a feeling that they are burned out though.
Lesson of the day: DCC Ready means - absolutely nothing. Sometimes it means you can just pop ina decoder, other times it means you cna pop in a decoder, but you need to do some rewiring to make it work and not fry the decoder the first time the loco derails.
In this case, if you keep the factory board and plug in to the 8 pin plug, it does just work. But between the poor quality light bulbs and the need to have as much room as possible for the biggest speaker you can fit for the best sound, it makes a lot more sense to remove the factory board. At that point, there are no assumptions to make - just follow the decoder instructions.
Al Mayo sells some great LED conversion kits on Ebay ....
http://www.ebay.com/sch/sellsellitall2011/m.html?_nkw=&_armrs=1&_ipg=&_from=
The micro LEDs are attached to a length of fiber optic that fit right in the Athearn headlight openings. Pretty good deal for what you get.