This installation of TCS MC2 Decoder is for HO Scale Bachmann Spectrum GE70 and was performed by Gary Groat.
Remove the shell and two (circled in red) screws.Take off the weight bar (as shown below).
Gently lift the light board up.
Slide off all six black, plastic protectors of the board and disconnect wires. Cut all three, yellow capacitors (placed on the motor) off.
Connect the two red ,power pick-up,wires and do the same to the black ones. Leave the red and black motor wires loose. (as shown in the picture above and below).
Close up of power pick-up wire connections.
Solder black motor's wire to gray wire of the decoder's socket and isolate with kapton tape. Solder the red motor's wire to the orange wire of the decoder's socket and isolate it with kapton tape as well. Solder the red wire of the decoder's socket to the red wire of locomotive's power pick-up and solder the black wire of the decoder's socket to the black wire of locomotive's power pick-up. Isolate all soldered contacts with a Kapton tape.
Put the "weight bar" back on the locomotive's chassis, place Red,Black,Orange,and Gray wire neatly under the "weight bar" and screw it down to the chassis with two philips screws. Use kapton tape to keep wires from sticking out of the chassis.
Cut both forward light LED's legs off ( as shown in the picture above).
Then solder one end of the Blue decoder socket's wire (the other end will be used to connect the reverse light as the Blue wire is the common lighting wire ) to the LED's Anode (+) and solder the White Decoder socket's wire to the one side of 680 Ohm resistor and solder the other end of the Resistor to the LED's Cathode (-) (As shown in the picture above). Isolate the resistor wires with shrinking tube or Kapton tape.
Solder the Yellow Wire of the Decoder's socket to the 680 Ohms Resistor and to the Cathode (-) of SMT LED ( Cathod is denoted by a white dot on the gold mounting pad). Scrape off the copper trace that connects the board to the LED. ( circled in red.) The purpose of it is to allow the Decoder to control the light.
Scrape off the copper trace located under the board as shown in the picture above.
Solder the other end of The Blue (common light wire) wire to the Anode (+) of SMT LED.
That is the picture of finished installation before the shell is put on. Use some black electrical tape to tape the MC2 decoder around so that you will not be able to see its body through the Cabin's windows.
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