This installation is for a HO-Scale Athearn SD40T-2 using a TCS WOW121-Diesel Decoder, RTR-MB1 Motherboard with built in Keep Alive® and UNIV-SH4-C WOWSpeaker kit by TCS.
HO-Scale Athearn SD40T-2 shown prior to installation.
To start off this install, we must first remove the front and rear coupler screws highlighted above in red and their housings.
With the couplers removed, while gently pulling outwards at each end and along each side of the frame, lift the shell off of the frame.
Take care to release the handrails as you lift off the shell so they don't break.
The Athearn SD40T-2 shown with the shell off. Remove the wires from the original lighting board and remove it from the chassis.
With the original lighting board removed, trim, tin or lengthen the wires as necessary.
Using the bottom clip, attach the RTR-MB1 to the chassis and solder the motor and track pickup wires according to the included wiring diagram.
When attaching the wires to the pads, it is not necessary to insert the wires through the holes. We recommend attaching the wires flat on top
of the solder pads.
The RTR-MB1 has a motor pick up clip pre-attatched to the bottom, so mounting it onto the locomotive could not be easier.
Remove the two screws highlighted above in red and remove the weight from the chassis. This weight will not be used to allow space to
accommodate the speaker assembly.
With the 25mm X 14mm speaker inserted into the UNIV-SH4-C enclosure, using double sided foam tape, mount this assembly
securely into the roof of the shell in the rear as shown above.
If your speaker enclosure installation covers the portholes on the enclosure, we recommend adding new port hole(s) similar to the original porting. Be sure that the new portholes are the same size and amount of the original and are vented freely into the locomotive We have found introducing a port of the correct size greatly increases the volume and sound quality of the installation. Too much or too little porting decreases the sound quality.
NOTE: In this installation, the open fans on the roof have loose fan blades. In order to prevent vibration which could compromise the sound quality,
we recommend that you add a small drop of model glue to the junction of the fan and spindle to prevent this movement.
Solder the speaker and lighting leads to the RTR-MB-1 according to the included wiring diagram.
In this installation, we used all the original 1.5 volt bulbs as the RTR-MB1 includes solder pads for both 1.5 v bulbs.
You could also add LEDs to this installation if you so desired.
TCS motherboards include on board current limit resistors for LED use. There is no need to apply external resistors for LED use.
Shown with the shell lighting and speaker reattached to the RTR-MB1.
You can now plug in your WOW121 decoder.
Now you can close up the locomotive and reinstall the coupler assemblies. Be sure to be mindful of wire routing and reassembly of the shell as to not damage or foul the installation. Your Athearn SD40T-2 is now WOWSound equipped and ready to roll!
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
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