This installation of TCS T1 Decoder is for HO Scale Tiger Valley Models C630 and was performed by Jean Lacroix.
First, you will have to locate and remove all the screws that hold the body underneath the locomotive. Normally you have 2 screws in the front under the cab and 2 other at the opposite end near the steps. Remove the shell and the cab of the locomotive. Remove all lamps hooked to the motor or otherwise installed. If they are of 1,5 volts you should discard them and save them for future projects.
In the example shown, the motor is a Sagami and is already insulated, so you do not have to bother to isolate it from the frame or the body. You can add extra contacts made of phosphor bronze wire inserted in plastic tubing for each truck in order to have a better electrical pick up current from the track.
You will need to unsolder the wires that were hooked to the motor. You will then solder the black wire from the harness to one of the truck screw and the red wire to the other truck contact screw. After this is done, you have to solder the grey harness wire on one of the motor contact and the orange on the other. It is suggested strongly to use heat shrink tubing to cover all exposed nude wiring or soldering made between wires. You will find heat shrink tubing in electronic parts stores across the country, like Radio Shack.
Then, it is a good idea to take care of the lights. I used Leds to replace the original 1.5v bulbs. Solder the blue wire from the harness to the “+” side of your Led and the “-“to a 680ohms (1/4watt) resistance and then the opposite side of the Led should be soldered to the white or yellow wire. The lights were simply glued behind the holes for the headlights.
You can use “Tack’NStick” adhesive (sticky paste) or double-sided tape, to stick the decoder on the locomotive floor. This leaves room enough to later add a sound unit to your locomotive. The green and violet wires can be cut and put electrical liquid tape at their ends. You are now ready to reassemble your locomotive doing backwards what you have done in order to disassemble it.