I'm starting to convert my fleet to DCC. I bought a bunch of Digitrax DH165A0 decoders pretty cheap last weekend at TrainFest in Milwaukee, WI so I could get started. I thought my older Atlas locomotives were going to be pretty tough to upgrade, but it's actually a fairly easy process.

First remove the shell of the locomotive. Removing the walkways is optional. I removed them because I'm pretty clumsy and I'd probably break most of the hand rails.

Using an exacto knife or a small screw driver, gently pry the copper wire out from under one of the middle tabs. You could also push it out using a small screwdriver if that's easier for you.

Next do the same for the tab on the end of the same side.

Now pry out the wire out from under the other middle tab and the wire should spring free.

Do the same process for the other wire, and then remove the light if you haven't already. Once all the wiring is removed, gently straiten out the thin copper strips.

Remove the plastic lightboard by inserting a knife or very small screw driver between the plastic tab and the lightboard.

Using a piece of the copper wire remove from the light board, make a small U shaped wire to fit in the pair of holes that match up with the copper strips. The end of my needle nose pliers happened to be the right width. Carefully solder them in place.

Put the copper tabs into the holes formed by the piece of U-shaped wire and the decoder. Slide the decoder over the plastic tabs until it latches down. Use your knife blade to guide the decoder over the plastic tab; this will greatly reduce the amount of force needed to "click" it into place.

Once the board is in place, fold the copper strips back over themselves. From my testing, this provides enough electrical contact to reliably operate your locomotive, but you could add a dab of solder if you really want to be through.

Gently pry open the metal ends on the pickup wires so they fit over the tabs on the decoder. Don't pry too far; we want the connectors to fit snuggly on the board. Attach all 4 pickup wires. Again, solder if you think its necessary (I don't).

Lighting depends on a lot on the individual locomotive. My locomotives had two long pieces of clear plastic that ran to the middle. I trimmed the ends of the plastic just after the attachment points for the roof support. This allowed me to solder my LEDs directly to the decoder and bend them up into place. A few small pieces of electrical tape on the LEDs prevents most of light from spilling into the other end. A small piece of styrene could be glued vertically into the top-middle of the shell to really block out the light if needed.