Installing DCC in a Large Scale 4-4-0

[mapper65]

I'm trying to install a Digitrax DCC decoder in a Eureka & Palisade Large Scale 4-4-0. The Bachmann drawing shows the stock DC wiring and they include a drawing for wiring in a DCC decoder.  The DCC drawing shows the wiring for a Lenz 1835 decoder. I connnected the track power and motor leads to my Digitrax decoder and the thing runs fine. What I can't get to work is the lighting.

I printed out the manual for the Lenz decoder to compare with the Digitrax decoder and as far as connecting up the head light and firebox lights, it seems like that information is not correct.  They show A,C & D on the Lenz decoder being connected to the black wire and terminals 3&4 on the Bachmann factory board. If you compare that to the Lenz manual, it looks like they are wiring the forward lighting output to the black lead and C&D on the Lenz decoder appear to be function outputs.  That kind of makes sense but they don't show the blue + wire being used. In my past experience, the blue wire needs to be used to complete the circuit.  Nothing is shown on the Bachman drawing as to what terminals 3&4 do.  The black wire on the Bachman drawing looks like it goes to the "-" side of the headlight.

Does anyone know the correct wiring for the lighting. I could easily cut the headlight wire and wire it directly to the decoder with a resistor but the firebox lighting would be a little more tricky since you can barely get to those wires due to them being on the side of the board that is still pretty much in the boiler when you slide the board out.  I have to believe that since Bachmann shows the loco wired to a decoder that the lights can work properly with a decoder.  I think something got lost in the translation of the drawing.  I'd like to not have to cut the firebox light wires and hard wire to the decoder if possible. Any help would be greatly appriciated. Thanks

[whitepass]

Hi

I have installed decoders to several Spectrum steam engines ,including 4-4-0 and have experienced similar problem with the lights.
What I have done is removed the stock board and wired the decoder in directly. In all cases I have used Massoth E motion XL decoder . This set up always worked.

In regards to the lights in the fire box. You can gain access to the fire box by removing the 4 screws that hold the cab, then very gently lift on the cab , making sure that all the fixtures that attach to the cab don't get damaged. Once the cab is off , gently use a tiny screw driver to pry the fire box portion away from the the rest of the boiler. Then remove the 2 screws holding the fire box light PC board. I have replaced the 2 diodes with, led's from sierra  and wired them directly to the decoder.

Hope this helps

og

[mapper65]

You mention removing the two diodes and replacing them with LEDs. I haven't tried removing the firebox circuit board yet but the Bachmann DCC wiring diagram already shows those as LEDs.  What diodes did you have to remove?

[whitepass]

You are correct these are led , I do believe that there is a resistor on the Bachmann fire box board. The sierra led"s have the resistor soldered to the wires directly.

[mapper65]

OK everyone, I just finished the installation of the DCC & Sound Decoder.  Here is the proper wiring and I didn't need to remove the Bachmann factory board or cut any wires or wire the lighting directly to the decoder.  I used a Digitrax DG583S decoder.  I used a separate Tsunami 1000 Light Steam in the tender for sound which is pretty straight forward so in this example I'm only going to explain how to wire the decoder in the loco for the motor and lighting.  I'm going to try and save everyone else a whole lot of time on this project by explaining how to wire this.  I have read where people doing similar locomotive have either removed their factory board or have cut their fire box lights and have wired everything including the headlight direct to the decoder.  That will work but I have to believe that this is a whole lot easier and this entire installation of the motor and lighting decoder should take you about an hour, possibly less.  I suggest having the DC & DCC schematics that came with the loco handy for reference.  My biggest surprise in getting this working was that in the past you always had to use the blue + common wire on the decoder.  With this method you will not need to do that, the lighting will get it's + reference from the Bachmann factory board.

Here goes...

Motor
Remove the red & black wires from terminal block 7 & 8 on the Bachmann Factory board.   Connect the black wire to pin 1 on the decoder and connect the red wire to pin 8.  These are the track power connections on the decoder.  In the box with the locomotive they gave you two short wires, one red, one black.  If you don't have those, make two wires up about 4 inches in length and preferably black and red.  Connect the black wire to terminal 8 on the Bachmann factory board and connect the red to terminal 7 on the Bachmann factory board.  Now take the other end of the black wire and connect it to pin 2 on the decoder.  Take the other end of the red wire and connect it to pin 7 on the decoder.  These wires power the motor.

Lighting
There should be an orange jumper wire and a white jumper wire on the Bachmann factory board between terminals 4&5 and terminals 3&6.  Remove those wires, you're not going to need them.  On the Bachmann factory board there will be a black wire on terminal 2.  Remove this wire from terminal 2 and connect it to your decoders Forward Light Output.  On the Digitrax decoder, this is the solid white wire which is 5th from the left on the wiring harness.  I soldered mine and used shrink tubing to shield the solder joint.  Next, on the decoder's wiring harness, wire Function Output 5 (white/green stripe wire) to terminal 3 on the Bachmann factory board.  Then, take Function Output 6 (white/blue stripe wire) on the decoder and connect it to terminal 4 on the Bachmann factory board.  Output 5 will control the firebox lights and I have no idea what Function output 6 does but Bachmann show this connected.  You may chose not to connect it.

I would suggest testing this before your put it all back together.  I found on mine that in order for the headlight to light be on in the forward direction, the switch inside the smoke box needed to be set for Large Scale.  If it was set for NMRA then the light was on only in reverse.  You could also correct this by changing a CV value.  

Be sure you put something between the bottom of the Digitrax decoder and the top of the Bachmann factory board to keep the two from shorting out.

Also, the smoke unit will still work by turning it on and off in the smoke box.  I took a voltage reading on the LM7812 voltage regulator and everything looks good.  I had around 15 volts DC on the input and 12 volts on the output.

That's it.  

[mapper65]

OK everyone, I just finished the installation of the DCC & Sound Decoder.  Here is the proper wiring and I didn't need to remove the Bachmann factory board or cut any wires or wire the lighting directly to the decoder.  I used a Digitrax DG583S decoder.  I used a separate Tsunami 1000 Light Steam in the tender for sound which is pretty straight forward so in this example I'm only going to explain how to wire the decoder in the loco for the motor and lighting.  I'm going to try and save everyone else a whole lot of time on this project.  I have read where people doing similar locomotives have either removed their factory board or have cut their fire box lheadlight wires and have wired everything direct to the decoder.  That will work but I have to believe that this is a whole lot easier and this entire installation of the motor and lighting decoder should take you about an hour, possibly less.  I suggest having the DC & DCC schematics that came with the loco handy for reference.  My biggest surprise in getting this working was that in the past you always had to use the blue + common wire on the decoder.  With this method you will not need to do that, the lighting will get it's + reference from the Bachmann factory board.

Here goes...

Motor
Remove the red & black wires from terminal block 7 & 8 on the Bachmann Factory board.   Connect the black wire to screw terminal 1 on the decoder and connect the red wire to screw terminal 8 on the decoder.  These are the track power connections on the decoder.  In the box with the locomotive they gave you two short wires, one red, one black.  If you don't have those, make two wires up about 4 inches in length and preferably black and red.  Connect the black wire to terminal 8 on the Bachmann factory board and connect the red to terminal 7 on the Bachmann factory board.  Now take the other end of the black wire and connect it to pin 2 on the decoder.  Take the other end of the red wire and connect it to pin 7 on the decoder.  These wires power the motor.

Lighting
There should be an yellow jumper wire and a white jumper wire on the Bachmann factory board between terminals 4&5 and terminals 3&6.  Remove those wires, you're not going to need them.  On the Bachmann factory board there will be a black wire on terminal 2.  Remove this wire from terminal 2 and connect it to your decoders Forward Light Output.  On the Digitrax decoder, this is the solid white wire which is 5th from the left on the wiring harness.  I soldered mine and used shrink tubing to shield the solder joint.  Next, on the decoder's wiring harness, wire Function Output 5 (white/green stripe wire) to terminal 3 on the Bachmann factory board.  Then, take Function Output 6 (white/blue stripe wire) on the decoder and connect it to terminal 4 on the Bachmann factory board.  Output 5 will control the firebox lights and I have no idea what Function output 6 does but Bachmann show this connected.  You may chose not to connect it.

I would suggest testing this before your put it all back together.  Be sure that the decoder board or the Bachmann factory board are not touching anything that can short them out.  When I tested mine I found that in order for the headlight to light be on in the forward direction, the switch inside the smoke box needed to be set for Large Scale.  If it was set for NMRA then the light was on only in reverse.  You could correct this a few different ways by changing a CV, wiring to the reverse light function output to the headlight or even swapping the power leads.  Probably easiest to leave well enough alone but it's your call.  I still have to run this on DC and see how it acts, that will determine what I end up doing to correct this minor issue.

Be sure you put something between the bottom of the Digitrax decoder and the top of the Bachmann factory board before pushing them back into the boiler in order to keep the two from shorting out.

Also, the smoke unit will still work by turning it on and off in the smoke box.  I took a voltage reading on the LM7812 voltage regulator and everything looks good.  I had around 15 volts DC on the input and 12 volts on the output.

That's it.  

[Mark Oles]

You didn't happen to take any pictures of the bachmann board, did you?  I have a first run 4-4-0 that I am putting the aristo REVO in and it is a similar situation.  I am considering just forgetting about the flickering firebox.  I could just run the aristo revo and the bachmann board in parallel (motor and lights controlled by revo, smoke and firebox by bachmann).

[mapper65]

I have a picture of it but I don't believe that you can post pictures on Bachmann's site.