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Updating a Yellow-box Atlas Kato loco to DCC -- what are the parts needed?

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  • Member since
    February 2021
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Updating a Yellow-box Atlas Kato loco to DCC -- what are the parts needed?
Posted by crossthedog on Thursday, April 15, 2021 12:30 AM

I have an Atlas Yellow Box RS-1 made in Japan by Kato. I often see DCC/sound decoders for sale, and now I'm seeing one that would seem to be specifically made for RS-1s locomotives made by Atlas Kato and Athearn, among others. What are the things that are needed to go from DC to DCC. Is it just the "decoder" or do I need a speaker, too? And what about these pins (8, 9, 21 etc.); sellers are always careful to specify the number of pins, which makes me think I need to also buy some other part that has something for the pins to plug into. I don't want to buy a "decoder" and find out that I need a lot of other stuff, too. I know that really old locos whose motors are screwed to the chassis are difficult to update to DCC, but I think I've heard that YB Atlas models are not of that sort. In fact I also have a YB Atlas RS-3 that was successfully converted to DCC/sound before I bought it. Can anyone break it down for me? What are the essential parts of a DCC makeover? 

Thanks in advance,

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

  • Member since
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  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, April 15, 2021 1:02 AM

Hi Matt,

This is about as clear an explanation as is available for installing a sound decoder in your locomotive. TCS decoders are very high quality:

https://tcsdcc.com/installation/ho-scale/629

You don't need the fancy miter box to cut the headlight light tube.

You will need a decent soldering iron. I recommend a temperature controlled iron from Xytronics something like this:

http://www.xytronic-usa.com/shop/item.aspx?itemid=26

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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    January 2010
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Posted by peahrens on Thursday, April 15, 2021 6:37 AM

hon30critter
You will need a decent soldering iron. I recommend a temperature controlled iron from Xytronics something like this: http://www.xytronic-usa.com/shop/item.aspx?itemid=26

If you want a less expensive good station, the 60w Xytronic the LF-389D is only about $60 and more than adequate for small work.

If you think you will get into hard wiring decoders it is best to stock up on the right supplies.  Those include solder, flux, heat shrink tubing, Kapton tape, small decoder wire.  

Paul

Modeling HO with a transition era UP bent

  • Member since
    February 2002
  • From: Mpls/St.Paul
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Posted by wjstix on Thursday, April 15, 2021 11:04 AM

Although the link to the TCS site does have a good explanation, note that you don't have to use their recommended (and more expensive) method of replacing the light board with their 'keep alive' sound board and then plugging a decoder into it. I've never had power pickup problems with any Atlas engine, so you could just install a decoder and (if doing sound) speaker with enclosure. You can get decoders that are the shape of the light board and snap in place of it, then you reconnect the wires to it and (if doing sound) hook up the speaker. You could also connect up a nine-pin harness that you could plug a decoder into. A good thing about that is you can use a non-sound decoder (much cheaper than a sound one) "for now", and then replace it with a sound one later. 

Stix
  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Thursday, April 15, 2021 11:58 AM

If yellow box is what I think it is, there isn't a socket to plug in a decoder.  The are boards that have a similar form factor (size and shape), ESU Direct is one

You strip out the old circuit board and hard wire the new one.

You are going to need a resistor and LED, 1000 ohm, 3mm warm white.  If you want to do business with China, you can get them cheap, albeit a longer wait for shipping.  Some decoders are set up to use LED's without resistors, you have to check on the requirements for the board you choose.

You will need appropriate size wire, which you can buy a pack of from the online DCC dealers.  You will also need some really small heat shrink tubing.

There used to be kits that included speaker and enclosure, there still maybe.   I'd recommend a sugar cube speaker that comes with an enclosure.

For completeness I will mention the Decoder Buddy.  It is a replacement for the circuit board.  They have plugs to accept various pin arrangements and soldering pads for keep alives.  You still need a decoder.

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    February 2002
  • From: Mpls/St.Paul
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Posted by wjstix on Thursday, April 15, 2021 2:53 PM

Some decoders have a CV controlling the output for the headlights so you can use an LED without having to add a resistor. Otherwise, Evan Designs offers several sizes of LEDs with the resistors and diodes already attached, so they can use any power supply up to 19V AC or DC.

https://evandesigns.com/products/universal-solid-leds-for-transformers

https://evandesigns.com/products/chip-nano-pico-leds

 

 

 

 

Stix
  • Member since
    February 2021
  • 1,110 posts
Posted by crossthedog on Monday, April 19, 2021 12:49 PM

Thanks everyone!

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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