This installation is for a HO-Scale Athearn MP15-AC using a TCS WOW121-Diesel Decoder, IB-MB1 NC Motherboard with built in Keep Alive™
VR 1.5 Voltage regulator and UNIV-SH4-C WOWSound 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-11 which was used for this installation.
IB-MB1-NC Motherboard with Keep Alive™ WOW121-Diesel Decoder UNIV-SH4-C Speaker Kit

Voltage Regulator

Click here for more information on the WDK-ATH-11 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 MP15-AC shown prior to installation.


    To start off this install, we must first remove the front and rear coupler screws highlighted in red 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 Athearn MP15-AC shown with the shell off. Unplug and remove the wires from the original lighting board. Remove the two weight and the board mounting
screws highlighted above in red and remove these components from the chassis.


In order to fit the IB-MB1 NC flush onto the frame, trim off the three frame mounting tabs as shown above in red.

With the original lighting board removed, trim, tin or lengthen the wires as necessary.
Using small lengths of TCS 3/32" and 3/64" shrink tubing, insulate these solder leads as needed.
As the IB-MB1 NC does not have connections for the original 1.5 volt bulbs, there are steps that must be taken to utilize these bulbs,
including adding in the included TCS VR1.5 Voltage regulator to supply a proper power supply.
To replace them all with LED's would not be feasible and you would lose look of the bulb lens face poking through the shell.
Before mounting the IB-MB1 NC, it is necessary to also bypass or 'bridge' the three LED current limit resistors on the bottom of the motherboard, highlighted in blue below as 'before' and 'after'.

To do this, add a small dot of solder to each end of the resistor, then taking a small length length of tinned wire, solder this wire as a 'bridge' onto the dabs of solder.
Trim off the ends of the wire. Here to the right, the resistors are shown with a properly placed bridge across the resistor.

With the resistors properly bridged, using double sided foam tape, mount the IB-MB1 NC to the frame and solder the track and motor leads to it according to the included wiring diagram.

After inserting the 25mm X 14mm speaker into the UNIV-SH4-C housing, mount this assembly with double sided foam tape to the front top of the shell interior.

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.


Solder the speaker leads to the IB-MB1 NC according to the included wiring diagram. At this point, we will add the TCS VR 1.5 Voltage Regulator.
This component has three wire leads. The first wire, the black and white striped wire, will be soldered to the negative cathode lead on the capacitor
highlighted in blue above. The VR 1.5 tan wire will become the common lighting lead and the blue will be the 12 volt lead as shown wired below.
The front and rear lighting leads previously combined will be soldered to the IB-MB1 NC according to the included wiring diagram. In this installation,
there is also a cab roof beacon light. This green wire lead was solded to pad #1 to be set for a rotating function.

The Athearn MP15-AC shown wired and ready for reassembly. To ease this, remove the top access panel and feed the VR 1.5 through it.
You can now plug in your WOW121 decoder. Fit the shell back onto the chassis and then place the VR 1.5 carefully into the shell and replace the access panel cover.
Now you can 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 MP15-AC 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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