This installation documentation is for the N-scale Kato SD40, specifically regarding the installation of a wired rotary beacon add-on. This installation uses the TCS CN-GP decoder and was performed by J.M.
Note: Comprehensive information on performing CN-GP installations can be found in our Classic N Installation Guide, and should be read before attempting this installation. A decoder installation guide for the Kato SD40 can be found here.
In this Kato SD40, I have installed a CN-GP. I chose the CN-GP because it fits the best in this locomotive, and also because I needed an extra light function to run a rotary beacon on the top of the locomotive.
Detail of milled frame and decoder wires
For this installation, I followed the steps of a normal CN-GP installation. Test fit the decoder, milled down the frame, isolated the frame from the motor, and wired the decoder, leaving enough space for the wires to run along the seam in the top of the chassis. The decoder fits and was tight so I was ready to wire the rotary beacon.
Close up of lighting function wiring
I needed to wire the beacon next so I connected one end of the rotary beacon to a 1k 1206 surface mount resistor at the first function pad and took the other end to the blue wire pad where the 5 volt output is. I then proceeded to connect the wires to the shell where they were mounted. Be sure to use caution when placing the beacon because the shell can melt. Now that I had everything wired up I needed to program my rotary beacon on the programming track so that it would function. I changed CV 51 to a value of 38. I then put the shell back on the locomotive and made sure the wires I added wouldn't interfere with the shell. Finally, I tested the locomotive to make sure my extra light function would work correctly.
Important Soldering Tip
Please do not use any flux either liquid or paste on the mother board. Over time, the acidic properties of liquid or paste flux will begin eating away at the fiberglass PCB and will damage it. Use only Rosin-core solder or no-clean flux approved for electronics use.
TCS recommends the use of Kester "44" Sn63 Pb37, .015" diameter Rosin-core solder. Kester part number 24-6337-0007.
You can order this solder from the following retailers:
Digikey - PN:KE1110-ND
Techni-Tool - PN:488SO6775
Other solder tips
When stripping wire, only strip a tiny little bit of the insulation. Strip no more then a 1/64 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire then half the length of the solder pad at most. In no case should solder or exposed wire wire ever be outside the boundary of the the solder pad you are attaching a wire to.
Click here for important information on properly Stripping and Tinning wire