This installation is for the N Scale Atlas C628 and uses a TCS AMD4 Decoder - performed by TCS.
First remove the shell by gripping it near the center of the locomotive and gently rocking it back and forth until it slips free.
Next, loosen the screws highlighted in red below just enough that you can slip the original lighting board from the chassis.
Your locomotive should look like the image below after the lighting board is removed.
Next install the AMD4 decoder into the chassis in the same orientation as the original lighting board.
NOTE: It is best to slip the motor tabs through the slits in the decoder as shown in the image below. The ensures both a strong connection, and proper isolation.
The image below shows the motor tabs slipped through the slots in the decoder with a bit more detail.
Once the AMD4 is mounted in the frame you can tighten the two screws back up, replace the shell, and you are ready to run!
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