According to Soundtraxx the Atlas board they make simply replaces the existing light board.
Springfield PA
Is the below your loco? If it is, then the light board decoder would work.
http://www.hoseeker.net/assemblyexplosionAtlas/Assembly%20Explosion%20Atlas%20U33C%2036C.jpg
I have a new Atlas GP40-2 with on board sound that has a different frame configuration and would not allow a lightboard type decoder. I would have to use a shrink wrapped decoder.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I would recommend Soundtraxx for that loco over digitrax hands down.
They have a decoder available for that loco found here:
http://www.soundtraxx.com/choose/step3.php?t=ho&s=Atlas
They also have a installation guide for the B23-7 which should be similar to yours.
http://www.soundtraxx.com/documents/appnotes/Atlas%20B23-7.pdf
It's been a while since I did my C 30-7, but I think it shold be similar. I replaced the OEM board with the Soundtraxx board making sure to get the right format I wanted for easy install. I put a 1.06" round HB speaker in the radiator area pointing up. I drilled out many holes for the speaker and weathered it so things blended. It sounds great. I did have to cut the speaker down in some areas.
The first thing I always do is remove the shell and check out what room is available and how things can be modified. Then compare to available speakers and board types.
Richard
Hello. I'm currently planning on installing a digitrax sound decoder into my Atlas U-33C. Does anyone know how to install this decoder and where and how to mount the speaker in the engine?
Freelancer with an interest in N&W, SCL, and other 70s railroads