hardwiring for dcc advice needed

[ncc1701]

My current locomotive project includes hardwiring a locomotive. This is the first time I have done this, and I am clear on all the issues involved except the unique problem of smaller scales in regard to physically fitting the decoder into the locomotive shell. The loco is a dcc ready spectrum 2-8-0 in N scale and the decoder is a digitrax dz-143 decoder. Anyway I see it, I will need to shave some weight off of the cast frame.

I really do not want to do this! I have had very bad experiences with metal filings and motors, and I have no Idea how to disasember a steam locomotive and put it back together again with her drivers in quarter.

[r0bert]

a dz143 should fit in the space provided for the decoder, you may need to trim the excess shrink wrap on the decoder for it to fit,
also a dz125 is even smaller, as are the lenz mini series, so there should be no need to cut the chassis.

[ncc1701]

Thank you very much, I will try the 143 if I have to and get a 125 if that won't work.

[fieromike]

My current locomotive project includes hardwiring a locomotive. This is the first time I have done this, and I am clear on all the issues involved except the unique problem of smaller scales in regard to physically fitting the decoder into the locomotive shell. The loco is a dcc ready spectrum 2-8-0 in N scale and the decoder is a digitrax dz-143 decoder. Anyway I see it, I will need to shave some weight off of the cast frame.

I really do not want to do this! I have had very bad experiences with metal filings and motors, and I have no Idea how to disasember a steam locomotive and put it back together again with her drivers in quarter.

You don't need to disassemble the engine other than removing the shell.
This picture shows an in-process DZ123 installation. 
http://i171.photobucket.com/albums/u293/fieromike/Railstuff/100_0607a.jpg
Just remove the weight and its plastic tray(?), shave the excess heatshrink off the end of the decoder, and you're in business.
May I ask why you want to use a 4 function decoder on this loco?

Mike

[ncc1701]

Thank you for the picture-this helps a lot. In response to your question, I have had experience with, DZ123 and DZ143 decoders, and the DZ143 decoder seems to provide smoother speed control. This may just be a figment of my imagination.

Would the board of  a DZ143, be any larger than a 123?- Even with some of the heat shrink trimmed off of the end, it just dosen't want to fit in the cavity. Is there any danger of a short with the end of board touching the frame with the very end of the heat shrink trimmed?

[fieromike]

The 143 is a bit longer than the 123, but the 125 (replacement for the 123) is a bit smaller, and has bemf that the 123 lacks.  I needed to trim the heat shrink all the way to the edge of the board to get it to fit.  Just use a single layer of Kapton tape to insulate the board from the frame.

[ncc1701]

Thank you very much.