Fitting lights to destintion windows

[philsandy]

I have a Bachmann Class 416 2EPB, it has interior lighting, and is fitted with a Soundtraxx MC1 decoder. I'm converting the loco to a Class 504 and want to fit lights in the destination windows in the roof. The decoder is  21 pin, so no wires. Can some one advise how to wire this up?

[philsandy]

After some research discovered this model has illuminated headcode blinds. I assumed it didn't, as the actual LED for the headcode window (indicated by red arrow on photo) is missing on my model, but there are 3 terminals still there. I have some grain rice 12v bulbs that I was going to use to illuminate the destination windows. They work when I touch the wires from the bulb on the LH and middle terminals (as you look at the photo) but the bulb is quite dim, compared to when you put the wires directly on the  rail track. 

Can any one tell me why this is?   

 

 

Edited December 9, 2019 by philsandy

[Yardman]

It's designed to work with SMD LED's. Be careful the decoder may not be able to supply enough current for a lamp. If there are three terminals it is probably for a Bi colour LED to give directional lighting. a common return (usually +) and two negative feeds for each LED.

[philsandy]

21 minutes ago, Yardman said:

It's designed to work with SMD LED's. Be careful the decoder may not be able to supply enough current for a lamp. If there are three terminals it is probably for a Bi colour LED to give directional lighting. a common return (usually +) and two negative feeds for each LED.

 

Yes they are Bi colour for directional lighting. If the decoder is unable to supply enough current for 2 lamps would it be advisable to power the lamps directly from the wheel pickups?

[Yardman]

34 minutes ago, philsandy said:

 

Yes they are Bi colour for directional lighting. If the decoder is unable to supply enough current for 2 lamps would it be advisable to power the lamps directly from the wheel pickups?

Normally only one lamp would be lit at one time so providing this is within Decoder spec. you should be ok, but why not just use LED's? There will be resistors built into the PCB for this purpose. I wouldn't attemt to bring track voltage up to the lights, back feed a Decoder with track supply and its toast as could other LED's on board. Remember it's a square wave AC at somewhere arround 14-16 volts on the track. Usually I just remove any onboard lighting including PCB's and install my own. This photo is a DMU, but the situation is the same. It depends how far you feel comfortable in going. LED's are cheap and easy to get.

[philsandy]

2 hours ago, Yardman said:

Normally only one lamp would be lit at one time so providing this is within Decoder spec. you should be ok, but why not just use LED's? There will be resistors built into the PCB for this purpose. I wouldn't attemt to bring track voltage up to the lights, back feed a Decoder with track supply and its toast as could other LED's on board. Remember it's a square wave AC at somewhere arround 14-16 volts on the track. Usually I just remove any onboard lighting including PCB's and install my own. This photo is a DMU, but the situation is the same. It depends how far you feel comfortable in going. LED's are cheap and easy to get.

 

Thanks for your reply Yardman. I don't need the headcodes to be illuminated, so could I wire an LED (don't need to be bi-colour) directly to the terminals (red arrow on 1st photo) and fit the LED in the destination window in the roof, if so which of the 3 terminals would I use and what type of LED do I need? only needs to be a white light.

Edited December 9, 2019 by philsandy
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[Yardman]

You will have to test for it. A small multi meter set to voltage will tell you which terminals are live in the appropriate direction. You may have to turn a function on in the Decoder to get this. As to which LED, there's many sizes and colours, there's not just one white. Look here for a selection, there are many other suppliers too. Where you intend to locate it may decide the size of LED you need. You can see the LED's bridging the tracks in the roof of the DMU picture. I also used different LED's in the marker lamp and Route indicator positions as well as the destination blind. The ones shown are 0805's, Warm white LED's, 0603's and 0402's are smaller. Remember LED's are polarity conscious and need a series resistor to limit current if you are not using them in the location Bachmann intended. Brush up on your soldering skills if you intend to use SMD LED's, they are really tiny. If you connect them to different Function outputs on the Decoder you can control them as you like.

https://www.rapidonline.com/Catalogue/Search?tier=Surface Mount LEDs

Edited December 9, 2019 by Yardman

[philsandy]

27 minutes ago, Yardman said:

You will have to test for it. A small multi meter set to voltage will tell you which terminals are live in the appropriate direction. You may have to turn a function on in the Decoder to get this. As to which LED, there's many sizes and colours, there's not just one white. Look here for a selection, there are many other suppliers too. Where you intend to locate it may decide the size of LED you need. You can see the LED's bridging the tracks in the roof of the DMU picture. I also used different LED's in the marker lamp and Route indicator positions as well as the destination blind. The ones shown are 0805's, Warm white LED's, 0603's and 0402's are smaller. Remember LED's are polarity conscious and need a series resistor to limit current if you are not using them in the location Bachmann intended. Brush up on your soldering skills if you intend to use SMD LED's, they are really tiny. If you connect them to different Function outputs on the Decoder you can control them as you like.

 

Thanks again for your reply. Excuse me but electrics is not my strong suit, if I'm just effectively moving the headcode light to the destination window does the LED need a resistor?

 

Also the interior lights in the trailer car are not working, I removed the PCB  and found 2 wires, orange and brown were not connected to anything. These wires come from the coupling link (arrowed), so the trailer car's interior lights get their power fed from the motor car. 

Do you know which terminals the orange and brown wires should be connected? It looks like they may have been connected to 2 of the 3 terminals, marked 1 _ 3.

[Yardman]

If you just connect the LED to the Bachmann connections you shouldn't need an additional resistor. Can't help you with the wire colours as I don't have this model. Someone else may be able to help here. You need to find out if they are from the pickups or the decoder in the power car.