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Atlas ho S2 headlight problem

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  • Member since
    July 2006
  • 251 posts
Atlas ho S2 headlight problem
Posted by alcofanschdy on Sunday, June 21, 2020 8:37 PM

I have a couple of ho Atlas S2's with a flickering headlight problem. The light that is supposed to be off when the loco is moving flickers.  I have cleaned the track and the wheels on the locos and no change.  What else needs to be done and is there a youtube video that might help?  thanks in advance

Bruce

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Sunday, June 21, 2020 8:51 PM

Install a diode in series with the LED.


Mel



 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
    July 2006
  • 251 posts
Posted by alcofanschdy on Sunday, June 21, 2020 9:05 PM

I have no idea how to do that.  Any place I can get instructions on doing that?

  • Member since
    February 2008
  • 419 posts
Posted by UpNorth on Sunday, June 21, 2020 9:11 PM

Is there a decoder involved (DCC)  and is the decoder from Digitrax ?

 

Marc

  • Member since
    July 2006
  • 251 posts
Posted by alcofanschdy on Sunday, June 21, 2020 9:19 PM

no it is straight DC

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Sunday, June 21, 2020 9:30 PM

Reverse voltage spikes will cause an LED to flicker, install a diode in series with the LED.






Mel


 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
    July 2006
  • From: Bradford, Ontario
  • 15,797 posts
Posted by hon30critter on Monday, June 22, 2020 12:14 AM

Hi alcofanschdy,

In case you are not familiar with electronics symbols, let me try to explain.

A diode is a component that only allows electricity to flow in one direction. You will need something like this:

https://www.ebay.ca/itm/Lot-of-25-1N4148-Diode-Fast-Switching-DO-35/112055861781?hash=item1a170cc215:g:-7wAAOSwDZ9bu-RC

Diodes have to be installed pointing in the right direction. The arrow in the diode symbol points in the direction of the desired current flow. Rather than spending hours trying to figure out the proper current flow, just hook the diode up temporarily until you get the right setup.

The squiggly line represents a 1000 ohm resistor. Without a resistor you will fry the LED. There may be one in the circuit already, but if you add in a second resistor it won't affect the light. Resistors are not polarity sensitive, nor does it matter which side of the LED they are on.

https://www.ebay.ca/itm/100PCS-1-4W-0-25W-Metal-Film-Resistor-1-Full-Range-of-Values-0-to-10M/252838503547?hash=item3ade59647b:g:is8AAOSwi0xaH7vM

For doing your testing, I highly recommend a set of these:

https://www.ebay.ca/itm/10pcs-Double-ended-Crocodile-Clips-Cable-Alligator-Jumper-Wire-Test-Leads/171907566332?hash=item28067d4afc:g:izsAAOSw34FVBPfj

Hope this helps. Don't be afraid to ask more questions.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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