Great Job !

Thanks Greg ! I have a few of these laying around from years ago. I was going to pass them off at a swap meet, but with your excellent pictures, I too may break out the soldering iron and take a shot at it now. Since I switched to DCC, everything I have done has been a simple drop in, or change out, installation. Only thing I would add is a sound decoder with speaker since I have been so spoiled on the sound aspect of DCC. Now to get up the courage to tackle those brass loco's that have been laughing at me over on the shelf !

Really nice job.

Really nice job.

Sound install

There is a brief tutorial of a sound installation in one of these babies here:

http://www.mrdccu.com/install/hods/Atlas-S2-826004.htm

Sound tutorial link unavailable

When I clicked on the link given for the sound installation tutorial, it is unavailable. Is there an updated link?

Link

I think this is the link, although I would not call this a tutorial:

http://mrdccu.com/install/hods/Atlas-S2-826004.html

Which Hole For The Rear LED is +ve on MRC ATLS4 Decoder?

There are 2 holes on the MRC ATLS4 to solder in the white LED.  However, which hole is for the +ve leg of the LED.  I've attached a graphic of the schematic.  Is it A?  Or is it B?

That's a great question

For the life of me I can't remember and the instructions are no help. They indicate that the square pad for the front is the anode (long lead). There is no such designation for the rear. However, going by the diagram the graphic for the LED itself, if we can trust that, shows that the anode would connect to the "A" pad. I wish I could be of more help. If you are successful, let me know and I will annotate the original post just in case anyone in the future tries this.

Great job, thanks for the information.

I have an older Atlas RS3 and GP7 that need the NCE decoders. Tired of fighting hiding wires to hard wire something else. Question, where can you purchase Kapton tape? I see it mentioned in decoder install articles but it is not at the big box stores in my area.

Bill Michael

Kapton

I have ordered it from McMaster-Carr and also Litchfield Station. I find the most useful width to be 1/4". 

I did a quick Amazon search and found this:

https://amzn.to/45W9xhO

Likely a lifetime supply for DCC installs for less than 10 bucks.

Thank you

Love these forums where we can exchange ideas and information. 

Bill Michael

Kapton Tape Too Narrow - So I used Electrical Tape

The piece of Kapton tape included in the MRC ATLS4 decoder wasn't wide enough to come up the sides of the motor.  This is needed to insulate the motor from the loco frame.  So I cut a piece of electrical tape and used that.  It was a tight fit.  I used the original metal screw to pull the motor down into the loco frame rather than the plastic screw so that I wouldn't strip the threads on the plastic screw.  

Once I was satisfied that the motor was snugly in place, I removed the metal screw and replaced it with the plastic screw.  

To make sure that the motor was insulated from the loco frame, I put one probe of my ohmeter on the motor frame and the other probe on the loco frame.  The needle didn't move indicating the motor was insulated from the loco frame.  

In LED terms, the anode is

In LED terms, the anode is usually referred to as the +ve and the cathode is referred to as the -ve.  And the long leg is usually the +ve (anode).  However, when you start bending the legs, it's very easy to forget which leg is +ve and which leg is -ve.  

I made myself a little tester using a 9 volt battery, an on-off switch that's mounted on a short piece of vector board, some leads with small alligator clips on the end (and a 470 ohm resistor on one of the leads so that I don't blow the LED that I'm testing).  The key is to clearly label the vector board as to which side is +ve and which side is -ve.  (and also which side is "On" and which side is "Off").  

To test the LED, I simply hook the alligator clips to the legs of the LED, flick the switch and see what happens.  If it lights up, I know that I've got the proper orientation.  If it doesn't light up, I reverse the clips and see what happens.  

I've always found this graphic to be very helpful when working with LEDs.  

Good exchange but the NCE

Atlas S2 decoder

I have an old Atlas S2 - great runner - but I have never removed the shell to see what space is available for a decoder.  Thank you for your photos and the inspiration to start the project!

I've got a couple of these S2's and another in the mail.    I may be using a few in my 'disguised pusher engine' project (disguise the powered chassis under some sort of freight car body).

I will need to install a non-sound decoder in those to match the primary steam engine(s) they are pushing, ..so I will refer back to your installation thread here.

But my most basic question right now is how do you get the shell off??

I did find this video, but even here he starts out with the shell already off....
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