This installation is for a HO-Scale Athearn GP35 Early Version using a TCS WOW121-Diesel Decoder, RTR-MB1 Motherboard with built in Keep Alive®
and UNIV-SH1-C WOWSpeaker kit 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-5 which was used for this installation.

RTR-MB1 Motherboard with Keep Alive™ WOW121-Diesel Decoder UNIV-SH1-C Speaker Kit
Click here for more information on the WDK-ATH-5 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

HO-Scale Athearn GP35 Early Version shown prior to installation.

To remove the shell, carefully pry the shell outwards along each side of the frame at the tab highlighted above in red and 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 GP35 Early Version shown with the shell off.



The original lighting will need to be removed. To do this, on the front tab, carefully pry apart the small metal tabs holding it in place and lift it up and out.
We will later use this connection point to facilitate the front track pick up.

Shown with the front lighting assembly removed.

In the next step. we will remove the entire motor assembly. On the bottom of the frame are four plastic buttons. Using a screwdriver or blunt probe, carefully push these buttons in towards the frame to release the motor.

Shown with the motor assembly removed.

With the motor out of the locomotive, remove the plastic tabs from the bottom of the motor.

Next, remove the metal motor power clip found underneath the tabs from the bottom of the motor, being careful to be mindful of the small motor
brush spring underneath that will come out with it.

Bend the raised tabs flat into the metal around it to minimize them and solder the positive (orange) motor lead to the top of this strip.

Reattach the completed metal clip and spring and cover it with Kapton tape to insulate it.

For the second track pick up lead, solder a connection point to the top of each tab as shown above.

To insulate the new motor connections from the frame, place a small strip of Kapton tape on top of the original connection point in the bottom of the frame.
Reinsert the completed motor back onto the frame at this point.

Shown with the motor assembly reinstalled and wired.

To allow for one track pick up lead, solder two connection points to the original front light post.

Detail showing the front track lead connection points soldered.

The RTR-MB1 has a motor pick up clip pre-attatched to the bottom, so mounting it onto the locomotive could not be easier.

Clip the RTR-MB1 to the frame and solder the motor and track pickup wires according to the included wiring diagram and using small lengths of TCS 3/32"
and 3/64" shrink tubing, insulate these solder leads. 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.


With the 35mm X 16mm WOWSound speaker inserted into the UNI-SH1-C enclosure, using double sided foam tape, mount this assembly to the shell top.

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.

Using a small amount of hot melt glue, secure the new LEDs to the front headlight tube and cab light mount.

In this installation to prevent light bleed from the cab to the front headlight, we fashioned a small piece of plastic to isolate the cab area as shown above.

Using the same hot melt glue, secure the rear LED to the rear headlight tube.

Solder these three lighting leads to the motherboard according to the included wiring diagram. For this installation we soldered the front headlight to LED pad 1,
the rear to pad 2, and the cab light to pad 3.

We have found that LED light output is brightest when shinning directly into the end of the light tube, but in some circumstances they may be placed along the length
of the tube as well with satisfactory results. In doing so, white light LED output would be least affected, while non white LED output will be more affected by placement.

TCS motherboards include on board current limit resistors for LED use. There is no need to apply external resistors for LED use. 

The RTR-MB1 has a on board 1.5volt power supply to conveniently power all the original 1.5volt bulbs that come with your Athearn locomotive. The front headlight and rear light pads are configured for 1.5volt use. Additional 1.5volt pads are available for other connections for ditch lights etc. If you prefer to use LED lighting as an option, there are LED solder connection pads. Current limit resistors are built into the board so no external resistor are needed for LED use.

Installation shown complete.

You can now plug in your WOW121 decoder.

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 GP35 Early Version is now WOWSound equipped and 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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