This installation of TCS WOW121 Decoder is for HO Scale Athearn SD70M and was performed by TCS.

This was performed by our friends from DCC Xpress installations.
They offer high quality WOWSound installations for a flat rate complete with free return shipping!
You can find them at:

These items are available in the WDK-ATH-3 which was used for this installation.
GEN-MB1 Motherboard with Keep Alive™ WOW121-Diesel Decoder UNIV-SH1-C Speaker Kit
Click here for more information on the WDK-ATH-3 and the rest of the WOWDiesel Kits line.

Important Soldering Tip:
Please do not use any flux either liquid or paste on the mother board. It will damage it. Use only Rosin core solder approved for electronics use.
We recommend to use only Kester "44" rosin core, SN63PB37, .015" diameter, part number 24-6337-0007.
This can be ordered from Techni-Tool under Techni-Tool part number 488SO157

The Athearn SD70M with its shell on prior to the WOW121 Installation.


To begin this installation, unscrew the front and rear coupler box screws (circled in red) and remove the front and rear coupler pocket.

Shown With the shell removed. Unplug the original wire connectors and lighting board and remove it from the chassis.

The Athearn SD70M with the original lighting board removed. Trim and tin the wires as necessary.

Attach the GEN-MB1 motherboard to the chassis and solder the track and motor wire leads in place.

Next, while referring to the included wiring guide, solder the front and rear light wire leads to the GEN-MB1 motherboard. In this installation, we used Kapton tape
to secure the wires and prevent shorts during installation and operation.

With the 35 x 16mm speaker hard wired and inserted into the UNIV-SH1-C enclosure, mount this assembly using hot glue into the top of the shell as shown.
Solder the speaker wires to the motherboard and plug in the WOW121 decoder.

The speaker assembly installed into the top of the shell.

Lastly, in order to keep the wires neat and prevent possible shorts, lace the wires into a bundle using lacing cord, which is a wax impregnated string 
used for wire bundling and making harnesses. There are many choices of lacing cord available from Digikey
We use part number 802534B BK032-ND

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 SD70M locomotive is ready to roll!


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

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