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What type of headlight bulb is in Spectrum K4 Pacific?

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  • Member since
    December 2006
  • 116 posts
What type of headlight bulb is in Spectrum K4 Pacific?
Posted by Fawlty Logic on Wednesday, April 23, 2008 4:40 PM

Just converting a new in the box Spectrum K4 to DCC.  It was DCC ready but I am hardwiring it since the circuit board in the tender takes up too much room.  I can fit in two large oval speakers with it removed.

However, I once took apart a Spectrum steamer to get at the headlight (to replace it with an LED) and I don't want to do that again.  The Soundtraxx decoder I had around the shop is designed for 12-16V bulbs anyway.

But I don't know if the bulb in place is 12 V or 1.5 V with a resistor that was on the circuit board.  It glows faintly with a 9 v battery, but I don't want to touch some DC leads to it and blow it if it is 1.5 V

Does anyone know what is in place in these locos for a headlight?

Alternatively, I have a multimeter.  Can I use it to test the type of bulb?  I don't know much about the meters and I use it just to test continuity and stall current.  If so, what would be the reading if the bulb was 12-16V for example?

Thanks.

Fierce-throated beauty! Roll through my chant, with all thy lawless music! thy swinging lamps at night.
  • Member since
    July 2006
  • 3,312 posts
Posted by locoi1sa on Wednesday, April 23, 2008 5:06 PM

  The Headlight in my Spectrum 2-8-0 is an LED. The K4 should be the same. Easy to check with your multy meter. Set it for ohms and test the white and blue wire then reverse the leads if its an LED it will read one way and not the other. Then get a 1.5 volt D or C battery and hold it to the headlight wires and see how bright it is. If its bright then its a 1.5 volt bulb or LED if its dim then its a higher voltage bulb.

   Pete
 

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

  • Member since
    December 2006
  • 116 posts
Posted by Fawlty Logic on Wednesday, April 23, 2008 5:11 PM

Thanks, Pete, but no.  I know it is not an LED.  I did tlhe old "switchero" with the 9V battery.  This is an bulb.  Thanks for the testing tips.  I will give them a try.

BTW Bachmann Spectrums really can vary a lot.  I have a decapod with an LED in the tender and a bulb in the front.  Bachmann tech support did not know much about either installation....I guess there are so many production runs over time with some models.

Fierce-throated beauty! Roll through my chant, with all thy lawless music! thy swinging lamps at night.
  • Member since
    December 2006
  • 116 posts
Posted by Fawlty Logic on Wednesday, April 23, 2008 5:23 PM

Got it!

I did find a 1.5V battery around and it did not light up at all.

Restested 9V..it was dim

So must be 12-16V.....sure enough it was when connected to a DC power pack.

I just didn't want to pop a headlight bulb right off the bat, in these darn Spectrums which are almost impossible to open without breaking something....usually the front boiler cover.  Bachmann doesn't recommend even trying to get them open.

Fierce-throated beauty! Roll through my chant, with all thy lawless music! thy swinging lamps at night.

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