Installing rear bulb lighting

[JRP]

I'm sure this is easy for alot of you, but I am not sure on how to wire 2 (two) 12 volt 30amp 1.7 diameter bulbs with my decoder (into the rear of my GP-38 locomotive).  I am using an NCE D13SR decoder.  I have a single LED already wired and working fine for the front, but for the rear, I wish to use these bulbs. 

Each bulb has two wires.  I know that the yellow and blue decoder wires are for the rear lights, but with 2 bulb wires, where do you connect them?  Do I solder one bulb wire to the yellow and one to the blue?  Of the bulb wires, is one positive and one negative and if so, which one? 

Also, do you recommend a resistor  for each of these bulbs or can I operate them without resistors?  

Thanks in advance for your guidance here. 

JRP  Great Southwest and Pacific RR

 

[mikebo]

 I hope you mean 12 volt 30 milliamp bulbs, if so since they are 12 volt  you don't need any resistors.The bulbs can be wired in parallel. one lead from each bulb goes to the blue lead and one lead from each bulb goes to the yellow lead. Bulbs don't have any polarity so it doesn't matter which lead goes to which wire. Since they are 12volt they may get hot. You might be better off using 1.5 volt bulbs with resistors.

[JRP]

Mike,

 Yes, they are 30 milliamps (thanks).  I kinda thought this was how I connected these, but your instructions should help.  I'm also aware they may get hot, but I'm thinking I may not use reverse that often. I'll keep the 1.5 volt bulb suggestion handy too.

Regards,

JRP

[tstage]

JRP,

I assume that the two 1.7mm incandescent bulbs are for EACH lens of the rear headlight?  If so, is there any particular reason why they need separate bulbs?  Would they have been used independently - e.g. for Mars lighting?

I ended up using an LED for both the front and rear headlights of my GP38-2.  I'm just curious the reasoning behind using different types of bulbs.  Thanks.

Tom

[JRP]

Tom,

I have a single LED for the front as well and positioned it so it lights both vertical openings.  I should have done the same in the rear as both the 12 volt bulbs got a bit too hot and begain to melt the plastic.  I had set the bulbs in the openings after removing the lenses.  Not a good idea as I found out.  But with some careful cutting and sanding I think I can salvage the rear light area.  I think Mike's idea of using a 1.5 volt bulb with resistor is what I will end up doing, or use an LED like the front.  

 Lesson learned.

JRP

[jrbernier]

  Quite honestly, I would go the LED route.  You have already seen what too much heat can do!  LED's are basically 'cold light' and I have never had problems with them.  Your 12 volt lamps may burn out fast as the DCC function output usually puts out 13-14 volts and the lamp life is shortened.  And the heat they generate can melt plastic.  I have used 1.5 volt 1.2 or 1.6 mm lamps with 1K ohm resistors for MARS lights.  Super small LED's are available, but are also super expensive!

Jim