This installation is for a HO-Scale Stewart ALCO C628 using a TCS WOW121 Diesel Decoder, AK-MB1 Motherboard with built in 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

HO-Scale Stewart ALCO C628 shown prior to installation.


    To start off this install, we must first remove the front and rear coupler screws highlighted above 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 Stewart ALCO C628 shown with the shell off. Remove the wires from the original lighting board and then remove it from the chassis.

With the original lighting board removed, trim, tin or lengthen the wires as necessary.

In order to mount the AK-MB1 to the chassis, it is necessary to trim off the two plastic tabs highlighted above in red to create a flat platform.

Attach the AK-MB1 to the chassis using double sided foam tape and solder the motor and track pickup wires according to the included wiring diagram.
We used a piece of 1" wide Kapton tape, TCS part #KT4 to insulate the bottom of the new motherboard from the top of the motor.

Trim the LED's from the original lighting board and solder lead wires to them for reinstallation. We insulated these splice joints using TCS part #1320,
3/64" heat shrink tubing.


With the leads in place, using a small amount of hot melt glue secure the front LED onto the roof of the cab as shown in the above left photo. In this installation,
while you can replace the front LED in it's original holder, as the speaker will block the rear light we chose this arrangment to match the lighting intensity,
and then utilized the front holder to route the front LED wires through.
Using the same technique, secure the rear LED to the back as shown to the right and then with the 25mm X 14mm speaker inserted into the UNIV-SH4-C enclosure,
mount this assembly into the top of the shell using double sided foam tape.
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. 

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.

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.

With the interior of the shell fitted with the LED's and speaker, solder these leads to the AK-MB1 according to the included wiring diagram.

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 Stewart ALCO C628 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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