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Discussion Starter #1
I have a ho Bachmann SD70ACe with sound value and LED headlights, I want to add ditchlights and want them to go on and off together, Can I wire them together and not burn anything down?
 

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The decoder provides 12 V DC for headlights. No doubt the existing
headlight has the needed resistor. So. what voltage bulbs are
in the ditch lights? If 12 volts you could simply tap into the headlight
circuit. If they are LED do they include the required resistor? The
blue wire is headlight common and it is POSITIVE.

Don
 

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The short answer is yes. Now for the longer answer :). As DonR said, you will more than likely need to add a resistor, or a LED driver. Personally, I would wire them to separate outputs on the decoder, then tie them together via software. In other words, two ouputs, controlled by one on/off button.
 

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Discussion Starter #5
The model in question is a new Bachmann model 66004 which is headlights only, the shell is being replaced with a model 66008 that has ditchlights and headlights that are wired to a separate small board that needs a plug lead from the mother board which the motherboard does not have in the 66004.The quickguide that came with the loco has no information about the decoder other than F0 controls the lights. I can not see any resistors on the small board. There no resistors that I can see on the LEDs so I am assuming the resistors are on the bottom side of the motherboard. I think the board is made by soundtrax for Bachmann and it is call sound value by Bachmann. Any suggestions?
 

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Discussion Starter #6
The decoder provides 12 V DC for headlights. No doubt the existing
headlight has the needed resistor. So. what voltage bulbs are
in the ditch lights? If 12 volts you could simply tap into the headlight
circuit. If they are LED do they include the required resistor? The
blue wire is headlight common and it is POSITIVE.

Don
All light wiring are black, no colors
 

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Discussion Starter #7
I just heard back from Bachmann and they are not and will not stock the 66008 sound board so I hope I get a reply back from Soundtrax the maker of the Bachmann 66008 sound board.
 

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Discussion Starter #8
Just heard back from Soundtrax and they do not have a part # for the Bachmann 66008 loco as it is exclusive to Bachmann who does not and will not stock the board.
 

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Sherman

It is unfortunate the mfgr elected to use no standard wire colors.

That makes it more difficult to do what you want.
I would use the multimeter set to DC volts and locate the front headlight
wires. Give us the voltage. Then check the ditch lights to determine
their input voltage. If they match you connect the ditch lights with
the headlights. If they don't match what headlight voltage did
you find? Also what is the voltage rating of your ditch lights?

Don
 

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Discussion Starter #11
Good question on the voltage of the ditchlights or for that matter the headlights. Bachmann does not give that info but I would assume that they are the same voltage as the headlights since they are connected to the same board in the 66008 model. The problem is ---I can't check the voltage to any of the lights because there is no power outlet to connect the light board to the main board which is the original 66004 loco that had head and tail lights only.Bachmann builds to locos on the SD70ACe frame models with headlights only and models with head and ditch lights, the only difference I can see one model has ditch lights and the other does not but there is a difference in the mother boards made by Soundtrax and that is the connecter with power to drive the light board in 66008 model where the 66004 model without ditchlights does not have that power connection and it wires the lights direct from the board. There is not additional function connection to the board so ditchlights if to be used need to be connected to the headlights. Bachmann nor Soundtrax sell the sound board for the 66008 model isn't that interesting. Since noone seems to know much about these Bachmann locos I will probably will connect the ditchlights to the headlights ans see what happens----I will wrap it tight so the smoke can't get out.
 

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Discussion Starter #12
This is a good reason not to buy the Bachmann SD70ACe at $319.00 MRSP with such a poor info and parts support.
 

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Discussion Starter #14
Thanks for the lead DonR, it does not answer where the resistors are if there are any and it is not specific on the type of bulb used----in my case the both the 66004 and the 66008 have LED lights. I am new to trains and DCC but am finding that particulars about product info using my situation as an example among the manufacturers is at best poor, there is little to no correlation between the makers and the products.It seems that things are made to mnrra standard but the sorting is left to the modeler. As sanother example I use Digtrax for DCC and some of their encoders but you when you have light problems they don't go past F0 the rest is up to the modeler which maybe it should be that way but it can be very frustrating.
 

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I would just wire them in using a 470ohm resistor. If there are too dim you can always take it out or go to a lower resistance. If the polarity is wrong they just won't light, it shouldn't damage them. Just reverse the wires and try again.

Sent from my Moto Z (2) using Tapatalk
 

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Discussion Starter #16
Soundtrax has just verified that the mother board has the resistors for the LEDs on the board so I will use the original board and wire the ditch lights to the headlights and be done with it.
 

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I don't think you and wire the LED's together and have only one resistor, its likely that only one LED will turn on. Which ever LED fires first will drop the voltage and the others will not turn on. You need to get to the source before the head lite resistor and connect there and use a separate resistor to the ditch lights.
 

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Or find the resistor and jump it, then use individual resistors for each light. This would retain control functions that the board provides (if it does).

Sent from my Moto Z (2) using Tapatalk
 
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