Replacement decoder for MP15

I have used Soundtraxx 2 Amp HO decoders in my SW1200s with success

Thanks

 sing the soundtrack decoder did you need resistors for the original headlights? If so what did you use?

I'm converting a couple recent MP15's and SW1200's I purchased now, replacing the lights and decoder with Loksound and LED's from evan's designs I had left over.  The LED's are 3mm pre-wired for battery/regulated 12v they work great!   Will try and post some photos and video of the converted locos.

As Jim Scorse reported, I also have successfully installed a 2 amp Soundtraxx TSU2200 in my AtlasO SW.  A very smooth runner.  I wish Atlas used a version of their horizontal single motor drive in all their diesels.  My China drive Atlas units draw more current, do not start as smoothly, and I dislike that the motor/enclosure is visible in the cab. 

With White LEDs you can use anywhere from 1K to 3.3K Ohm resistors.  I generally use 2.7K (because I have a lot of them).  They are very bright with 1K.

I've had some success with Loksound HO Select in Atlas MP15s and SW9. There's a new Loksound V5DCC that's just come out which has better sound quality and improved motor control. I added TCS Keep Alives and also replaced the speakers with Tang Band 1925s.  As recommended above, I use 1k resistors with the 3mm LEDs in the headlights, and with the 1.8mm LEDs in the ditch-lights I added. 1k leaves them bright for sure, but the Loksound decoders have 31-step brightness adjustment for the lighting functions. Good for dimming as well. The MP15Dcs in action:

Decoder use is all about current draw.    The Atlas SW seems to draw pretty light current.    To test a loco, simply put it on a stand or turn it over in a cradle and run it on straight DC with NO decoder connected.    Connect you ammeter in line with the feed and then stall the motor by stopping the wheels with your fingers if you are tough, or a wood block if you are not into pain.    Watch the meter and see where it peaks before th stall.   

I have two older Atlas SWs with Soundtraxx and they seem just fine to me.

Right on Jim.  My SW and MP15DCs seem to draw about 1.3A stalled.  In normal running they draw about 0.8A max. I have never had an HO decoder (Tsunami1, TCSWOW or Loksound) fail in use in these locos.  However, a few caveats apply:
- All my locos are weighted such that they reach wheel spin before stalling
- My layout has no grades, although my minimum radius is 36"
- My longest train is 25 cars at 1lb each plus a van with the drag of wheel pickup wipers
- Top speed is limited to about 25 scale MPH on my layout.