Installing a Digitrax DH123 decoder in this crowded
switcher is not easy but it is possible.
Remove the shell by carefully pressing the four tabs. Two tabs
are shown in the photo. Press them one at a time toward the centerline
of the locomotive. Press them just far enough to loosen the shell
but not far enough to break them off. (If you do break one, glue
it back on with Testors liquid cement for plastics and wait at least 24
hours before reassembly.)
Disconnect the four truck wires and the two motor wires from the stock
lighting board. These can be unsoldered from the board or just clipped
off close to the board.
Locate the four mounting tabs indicated by blue arrows. Remove
the board by pressing the four mounting tabs to release it or simply clip
off the tabs with a nail nippers or a knife. With the board removed,
trim the mounting tabs even with the top of the motor.
Remove the weight by removing four screws, two of which are indicated
by red arrows. Note how the wires for the front truck thread through
the weight.
Cut a piece off the back of the weight, as shown. Be sure to
leave the mounting screw holes in the large piece. This weight is
hard enough to hold in a vise and cut with a hack saw but still soft enough
to cut with a wood blade in a band saw. If you use a band saw, be
sure to use a pusher stick.
Now cut a second piece out of the back of the weight. This will
require two saw cuts, one just above the screw holes, and one through the
wiring slots. Clean the cuts up with a file.
Remount the weight using the original screws. Bring the truck
wires up through what is left of their original slots.
