This installation is for HO-Scale Stewart F7A using a TCS WOW121-Diesel Decoder, AK-MB1 Motherboard with Keep Alive™
and UNIV-SH4-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-ATL-2 which was used for this installation.
AK-MB1 Motherboard with Keep Alive™ WOW121-Diesel Decoder UNIV-SH4-C Speaker Kit
Click here for more information on the WDK-ATL-2 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

Stewart F7A shown with the shell on prior to installation

To start this installation, remove the front coupler screw and coupler box. Next, spread the shell outwards from each side and lift it off of the chassis.

Shown with the shell removed. Next, clip off the wiring and remove the motor connection tabs from the original lighting board lifting it from the frame.
Discard this board along with the original lighting bulbs.

Shown with the lighting board removed. Trim, tin or lengthen the wires as necessary.

Solder new connection points on each of the original motor tabs, solder the motor wire leads to these and insulate them with shrink tubing.

Attach the AK-MB1 motherboard onto the frame and solder the track and motor leads to the motherboard.

Next, insert the 25mm x 14mm speaker into the UNIV-SH4 housing and using double sided foam tape, secure this assembly onto the frame.
Solder the speaker leads to the AK-MB1 motherboard.

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.

In this installation we used a sunny white 3mm LED in place of the original bulb. With new wire soldered to the LED leads, solder this to the AK-MB1 according
to your included wiring diagram.

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.


Using a small dab of hot melt glue, secure this LED onto the back of the headlight tube.

The above installation was done utilizing the 25mm X 14mm speaker and the UNIV-SH4C. We found this to produce the best sound, but presented that the enclosure was visible within the cab, to which we painted it black for a more minimal presence. As an alternate that we have used, you can also install the 35mm X 16mm speaker with the UNIV-SH1-C enclosure into the rear of the locomotive as detailed below. To accommodate this installation, the enclosure will need to be narrowed with a file to fit between the frame. If you would prefer this option, order the WDK-ATL3 kit instead.


To accomplish this fit, we marked the enclosure, filed the width slightly and it fits nicely in between the rear frame members,
secured with a small amount of hot melt glue.

You can now plug in the 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

Your Stewart F7A 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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