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Atlas Genset II, Soundtraxx Decoder and LED

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  • Member since
    March 2008
  • From: Poland
  • 111 posts
Atlas Genset II, Soundtraxx Decoder and LED
Posted by Arras88 on Thursday, March 20, 2014 7:40 AM

Hello,

I am installing a Tsunami decoder in my new Atlas Genset II. The manual says that I should add 680 - 1000 Ohm resistor to each LED.

However, I would like to use the original Atlas board with LEDs which looks like on the picture.


I am not an experienced electronic engineer but it seems that there are already two resistor on each board. Can I just connect these boards to the Tsunami decoder without additional resistors? 

Greetings,
Arras88

  • Member since
    September 2003
  • 10,582 posts
Posted by mlehman on Thursday, March 20, 2014 9:54 AM

Arras88,

Depends. The Atlas light board covers what will be two separate functions with the Tsunami. If there are any internal connections on the light board between front and rear lights, those will need to be severed or things will be wonky.

My thoughts are that a resistor for each headlight will take up less space than the Atlas board.

Mike Lehman

Urbana, IL

  • Member since
    January 2010
  • From: Chi-Town
  • 7,712 posts
Posted by zstripe on Thursday, March 20, 2014 10:06 AM

It suggests in the install, to not use the orignal board and put separate resistors on the Led's. There are only two wires on the Atlas board.

Frank

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, March 20, 2014 11:36 AM

 Is that board for the ditch lights? If you want alternating ditch lights you will have to do some rewiring. Careful tracing of the circuit on there would probably yied an option where you can cut the traces and add your extra wire yet keep those resistors in the circuit, one per LED. Those are 4.7K resistors which may seem to be high but SMD LEDs can be VERY bright, so cutting it back is probably a good thing.

         --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2001
  • From: SE Minnesota
  • 6,847 posts
Posted by jrbernier on Thursday, March 20, 2014 12:02 PM

  Randy is correct - The stock light boards do not support alternate flashing ditch lights.  Some rewiring or using the supplied SoundTraxx ditch lights can be done.

  About 2 years ago, I installed the MRC Genset sound decoder in one of the original gensets.  MRC supplied new ditch lights and the decoder was a pretty straight forward 'light board' replacement.  I had bad thoughts about the MRC decoder, but at the time no one else had the sound file.  The engine runs fine and the ditch light alternate flas depending on direction.  I just know if I installed another MRC genset decoder, it may go 'south'.....

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
    March 2008
  • From: Poland
  • 111 posts
Posted by Arras88 on Thursday, March 20, 2014 1:37 PM

Thank you all very much for help.
Yes, it's board for ditch lights. Tsunami has only six  Fx outputs so I am able to program ditch lights only for one direction.

The idea is to use the original Atlas SMD LEDs because I don't have enough LEDs to replace them.
For the front I will do as Randy wrote. I'll cut the circuit on the board, remove resistors and connect my wires with 1K resistors for each LED.

Because there is no more Fx outputs to configure ditch lights at the end I wanted to just use the original board and connect it to the backup light output.
But you advice not to do it so I will remove existing resistors as well, cut circuit and connect my wires with resistors for each LED separately. All three LEDs (backup light, and two rear ditch lights) I will connect to backup light output.

 

  • Member since
    February 2007
  • From: Christiana, TN
  • 2,134 posts
Posted by CSX Robert on Thursday, March 20, 2014 5:30 PM

Arras88
...Tsunami has only six  Fx outputs so I am able to program ditch lights only for one direction...

Six outputs is enough for headlight, taillight, and separate ditchlights on the front and rear, are you using some for something else?

Arras88
...I wanted to just use the original board and connect it to the backup light output. 

But you advice not to do it so I will remove existing resistors as well, cut circuit and connect my wires with resistors for each LED separately. All three LEDs (backup light, and two rear ditch lights) I will connect to backup light output. 

The advice to not use the original board is so that you can have them on separate circuits so they can flash alternately.  If you are going to have them on the same circuit, then I don't see any reason to not use the original board.

  • Member since
    March 2008
  • From: Poland
  • 111 posts
Posted by Arras88 on Thursday, March 20, 2014 6:17 PM

I am sorry for a mistake. Of course there are 4 outputs (the description of outputs FX5 and 6 is confusing):
1. Headlight,
2. Backup Light
3. FX5
4 .FX6

If I use Fx5 as a phase A ditch light forward and Fx6 as a phase B ditch light forward there is no more outputs for rear ditch lights. So my choice is to have only front ditch light working and the rear will be just solid.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, March 20, 2014 7:45 PM

 You'll probably want to use something like those 4.7K resistors instead of a 1K for the SMD LEDs. They are really bright. On Rick Bell's RPM Yahoo group they have all sorts of sound installs documented, one of them did something similar to a different brand loco - sliced the traces on the factory light board and then attached the wires fromt he decoder. I'm thinking if you do it in the right place you cna keep the LEDs AND resistors, and attach the wires fromt he decoder in such a way that the supplied resistors are still in the circuit, no other resistors needed. I'm have to see a clear closeup of both sides of that LED board to be able to tell just where to cut and where to attach which decoder wire.

                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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