This installation is for N Scale Kato NW2 uses TCS K3D3 Decoder and was performed by J.M.
First remove the shell by gently pulling it upwards with a slight rocking motion.
Next remove the motor clips with a pair of tweezers as shown below. Be careful not to bend these clips because you will need them for the decoder installation.
Next slip out the original lighting board by pushing it towards the front of the frame and then lifting it up and out.
Now reverse that motion to install the decoder. Place the decoder slightly in front of the tabs, and press it down while pushing it towards the rear of the locomotive. Be careful not to stress the parts on the decoder when you push it into place.
Now reattach the motor clips by first wrapping them around the motor's brush caps with a pair of tweezers, and then pushing them gently until they clip onto the decoder.
If the motor clips do not fit snuggly around the brush caps use a pair of tweezers to squeeze both sides of the motor clips at the bottom of the brush caps.
Now that your installation looks like the one below you are ready to put the shell back on and run your DCC locomotive!
IF YOU DECIDE TO USE THE THIRD FUNCTION OF THE DECODER FOLLOW THE TWO PICTURES BELOW:
The extra function has a built in resistor and therefore must be an 1.5V LED or 1.5V bulb.
Solder one side of the bulb/LED (anode) for the extra light to the pad circled in blue.
Solder the other side of the bulb/LED (cathode) to the pad (circled in red) on the bottom of the decoder.