Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

athearn gen. 1.5volt bulb replacement

1968 views
4 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    February 2010
  • 191 posts
athearn gen. 1.5volt bulb replacement
Posted by bnsf0823 on Friday, April 12, 2013 4:35 PM

I installed tsunami decoder in my sd70 mac and burned out some bulbs in the process not thinking I needed resistors.  what is the mm of bulb that I need for this athearn gen model and what ohm resistors do I need to install with it or should I just replace with led's?  Also can anyone explain exactly how to test my loco to see if the motor is isolated from the frame.  I like the looks of the bulbs over the led's but how big of a pain it is to replace sd 70 lights leds might be more logical for the longevity.  I am learning slowly and expensively how to work on my own trains.  I figure it will save me in the long run knowing how to do all of these tasks.  I have been great at frying decoders and burning up bulbs.  Thanks

scott

  • Member since
    January 2001
  • From: US
  • 154 posts
Posted by greendiamond on Friday, April 12, 2013 4:43 PM

If you are using the board replacement Tsunami decoders they have provisions for hooking up 1.5v bulbs without the need for additional resistors. 

I have used Minitronics 1.5v replacement bulbs.

Good practice when installing decoders is to use a 1.5v battery to test your bulbs to see how bright they are before wiring in to the decoder and having flash bulbs.

Mike Tyl

  • Member since
    March 2008
  • 409 posts
Posted by ba&prr on Friday, April 12, 2013 4:51 PM

If there are 2 wires going to the motor, it is isolated from the frame. The light bulbs should be 1.2MM size.Miniatronics sells these. The instructions that came with the decoder should tell you what resister to use. I think around 750 to 1,000 ohm 1/4 watt will work. If you get the Tsunami board style for Athearn units, they have the built in resisters for 1.5v bulbs. For the SD70MAC it should be part # 828052. Joe

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Friday, April 12, 2013 5:33 PM

What decoder did you use?

The decoders come with full instructions. I have the shrink wrapped and board type Tsunami and the instructions are very clear.

There are even some decoders with resistors for LED's but I do not think it is for your loco.

I am sure you know now, never, ever assume with DCC. There are many variables.

By the way, if you have a decoder with 1.5 volt connections. those will not work for LED's. Some have tried.

Some confuse LED's with light bulbs.

Below is a link you should look at,

http://www.members.optusnet.com.au/nswmn1/Lights_in_DCC.htm

A simple Google search or ask here, first would have been better. Many times I have found that a Google search got me an answer a lot quicker.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    February 2010
  • 191 posts
Posted by bnsf0823 on Friday, April 12, 2013 9:09 PM

The decoder I used was a board style tsunami type I believe the 710 style that is suited for the sd 70 series locos.  I followed all the steps In the instructions assuming that the motor was isolated from the frame of the unit, it does have two wires red and grey that lead to the motor from the old decoder.  and the bulbs that I used were factory bulbs so I know they are not led bulbs but I don't know if they are 12-14 volt bulbs how do I test that?  I soldered everything nice and neatly and used heat shrink around all my connections.  I hooked all the commons up to the 1.5volt area on the decoder including ditch lights.  I guess I can't understand what went wrong.  I sent the decoder back to soundtracks because it just wasn't working. 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!