This installation is for a HO-Scale Atlas C420 Ph1 high nose using a TCS WOW121 Decoder, AS-MB2-NC Motherboard with a KA4 Keep Alive™
and UNIV-SH4-C WOWSpeaker kit.

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-7 which was used for this installation.
AS-MB2-NC Motherboard WOW121-Diesel Decoder KA4 Keep-Alive™ UNIV-SH4-C WOWSpeaker Kit
Click here for more information on the WDK-ATL-7 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 Atlas C420 Ph1 high nose prior to installation.


To start off this install, we must first remove the front and rear coupler screws as indicated above in red and their housings.
With the couplers removed gently apply outwards on each end and along the shell and lift the shell off of the frame.
Take care with the handrails as you lift off the shell off so they don't break.

The locomotive with the shell removed. At this point, remove the wires from the original lighting board and release it from the frame.

Shown with the lighting board removed. Next, trim and tin or lengthen the wires as necessary for reconnection. Attach the AS-MB2-NC to the frame using
the mounting holes and solder the track and motor leads according to the included wiring guide.

Shown with the AS-MB2-NC installed.

Using double sided foam tape, secure the KA4 with Keep Alive™ to the front of the rear weight as shown and solder the connections to the motherboard.

Insert the 25mm x 14mm speaker into the UNIV-SH4-C enclosure and for this installation, to allow the speaker to fit onto the frame, we cut a small notch in the front bottom.
As the speaker enclosure will be visible inside the cab, we also painted it black to minimize it's appearance in the final installation.

Using the same double sided foam tape, mount the speaker assembly to the frame as shown, taking care to route the wires to avoid
potential pinches that could in the future lead to shorts.

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.

Next we soldered the original LED lights to the AK-MB2-NC.
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.

You can now plug in you 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

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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