Athearn AC4400 Decoder Installation featuring the RTR-MB1 Motherboard with Keep Alive®, WOW121-Diesel Decoder, and UNIV-SH1-C Speaker Kit by TCS.
Shown with shell on, prior to installation.
First, remove the coupler box screws and the coupler boxes from both ends of the locomotive.With the couplers removed the shell should lift right off the chassis.
Remove the wires from the original lighting board.
Then lift the lighting board up from the back of the engine to remove it.
Install the RTR-MB1 into the engine by clipping it to the motor like the original lighting board.
Though there are thru holes on the the tabs on the mother board for track power and motor power we do not recommend that you thread the wire though them. Please use the preferred method which is to tin the tab using rosin core solder only, tin the wire, then solder the wire to the tab by aligning it laying it straight down. Make sure the wire is short so that it does not go beyond the boundary of the solder pad. Please carefully note how neat and cleanly the wires are soldered to the tabs in this photo. There is no exposed wire off the edge of the the solder tabs. Never use flux for this solder work. Use only rosin core solder approved for electronics.
Next, wire the RTR-MB1 according to the wiring diagram in the motherboard manual. All the original 1.5volt bulbs supplied with the Athearn loco were used. The white wire solder pad is the forward 1.5v solder pad for the front lights. The yellow wire solder pad is the reverse 1.5v solder pad for the reverse lights. The solder pad marked "1.5V" is the common power source for the bulbs. This motherboard can be configured for LED operation as well, the mother board has built in current limit resistors for LED use. Consult the wiring diagram for LED use. Solder the two violet wires to your 35mm x 16mm WOWSpeaker, glue the speaker into the UNIV-SH1-C (we used hot glue, but CA would work as well) speaker housing and mount it under the fan housing at the rear of the engine.NOTE: You must be very careful to avoid getting glue on the speaker cone. Glue on the speaker will ultimately cause it to produce no sound and fail.
Finally, solder the speaker wires to the motherboard, plug in the WOW121-Diesel decoder, and replace the shell and coupler boxes.Your WOWSound equipped engine is now 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 than a 1/32 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire than 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
In order to keep the wires neat and prevent possible shorts, we recommend lacing the wires into a bundle using lacing cord. Lacing cord is a wax impregnated string used for wire bundling and making harnesses. There are many choices of lacing cord available from Digikey www.digikey.com.
We use part number 802534B BK032-ND