Walthers Mainline EMD SD70ACe

Scale:
HO Scale


This installation uses the following decoder:




This installation documentation is for the HO-Scale Walthers Mainline EMD SD70ACe locomotive. This installation uses the WDK-WAL-3 WOWKit, which includes the WOW121-Diesel decoder, WM-MB2 Motherboard, 28x18mm Micro Speaker with Enclosure, custom wire harness, and nylon screws. This installation was performed and documented by TCS' Dan M.

The Walthers Mainline EMD SD70ACe shown prior to installation. To begin the disassembly, flip the locomotive on its side and remove the couplers from each end. There are also two screws on the underside of the chassis on either end of the fuel tank which hold the shell down. Both of these screws also need to be removed.
The Walthers Mainline EMD SD70ACe shown prior to installation. To begin the disassembly, flip the locomotive on its side and remove the couplers from each end. There are also two screws on the underside of the chassis on either end of the fuel tank which hold the shell down. Both of these screws also need to be removed.
Shown with the shell removed and OEM motherboard and DC dummy plug. To remove the motherboard, start by unplugging each of the connectors. You may want to label them for later, as they will be re-used with the TCS replacement motherboard.
Shown with the shell removed and OEM motherboard and DC dummy plug. To remove the motherboard, start by unplugging each of the connectors. You may want to label them for later, as they will be re-used with the TCS replacement motherboard.
Shown from the top with the OEM motherboard still in place and all of the plugs removed. Remove the three screws near the corners of the motherboard and lift it out.
Shown from the top with the OEM motherboard still in place and all of the plugs removed. Remove the three screws near the corners of the motherboard and lift it out.
Shown with the OEM motherboard removed.
Shown with the OEM motherboard removed.
Shown from the top with the OEM motherboard removed. Remove the screw holding the speaker chamber over the rear truck (if installed from the factory).
Shown from the top with the OEM motherboard removed. Remove the screw holding the speaker chamber over the rear truck (if installed from the factory).
To install the WM-MB2, you MUST use the included nylon screws as shown. Do not use the original screws here or else the decoder cannot be installed! The third screw hole (top right) can use the original metal screw.
To install the WM-MB2, you MUST use the included nylon screws as shown. Do not use the original screws here or else the decoder cannot be installed! The third screw hole (top right) can use the original metal screw.
To install the speaker you should use double-sided tape, such a VHB (shown here).
To install the speaker you should use double-sided tape, such a VHB (shown here).
The plug and wires for the speaker can be routed through this hole near the rear of the chassis. The track power wires are also fed through this hole. The speaker wires can follow the tack power all the way back to the motherboard. Secure the speaker to the chassis in the area above the rear truck. The speaker faces downward towards the holes in the floor of the chassis.
The plug and wires for the speaker can be routed through this hole near the rear of the chassis. The track power wires are also fed through this hole. The speaker wires can follow the tack power all the way back to the motherboard. Secure the speaker to the chassis in the area above the rear truck. The speaker faces downward towards the holes in the floor of the chassis.
Begin plugging in the original wire harnesses such as the track power and motor.
Begin plugging in the original wire harnesses such as the track power and motor.
Plug in the INCLUDED 6-pin wire harness for the lights. DO NOT use the factory 6-pin wire harness or else your lights will not work correctly!
Plug in the INCLUDED 6-pin wire harness for the lights. DO NOT use the factory 6-pin wire harness or else your lights will not work correctly!
This harness will be included in your WOWKit from TCS, and is intended to replace the OEM one. This harness uses NMRA-standard color coding. Follow the instructions below to re-wire the lights properly using this harness.
This harness will be included in your WOWKit from TCS, and is intended to replace the OEM one. This harness uses NMRA-standard color coding. Follow the instructions below to re-wire the lights properly using this harness.
It is recommended to work with the harness connected to the motherboard so that you can trim and splice your wires as neatly as possible. This model is a tight fit with all of the wires, so try to limit your excess wire as much as possible!
It is recommended to work with the harness connected to the motherboard so that you can trim and splice your wires as neatly as possible. This model is a tight fit with all of the wires, so try to limit your excess wire as much as possible!
Shown with all of the harnesses connected and wires routed. This model is very finnicky about where all of these wires can fit, so use this as a guide. You may need to loosen the screws on the motherboard or remove it temporarily in order to tuck all of the wires underneath.
Shown with all of the harnesses connected and wires routed. This model is very finnicky about where all of these wires can fit, so use this as a guide. You may need to loosen the screws on the motherboard or remove it temporarily in order to tuck all of the wires underneath.
Finally, install the WOW121 Diesel decoder. Lace up and secure any remaining wires before re-installing the shell. Be especially careful around the cab area so as to not get the wires tangled into the drive axle and gearing of the front truck. Your locomotive is now WOWSound euqipped with Keep Alive® on-board and ready to hit the Mainline!
Finally, install the WOW121 Diesel decoder. Lace up and secure any remaining wires before re-installing the shell. Be especially careful around the cab area so as to not get the wires tangled into the drive axle and gearing of the front truck. Your locomotive is now WOWSound euqipped with Keep Alive® on-board and ready to hit the Mainline!

Important Soldering Tip

Please do not use any flux either liquid or paste on the mother board. Over time, the acidic properties of liquid or paste flux will begin eating away at the fiberglass PCB and will damage it. Use only Rosin-core solder or no-clean flux approved for electronics use.

TCS recommends the use of Kester "44" Sn63 Pb37, .015" diameter Rosin-core solder. Kester part number 24-6337-0007.

You can order this solder from the following retailers:
Digikey - PN:KE1110-ND
Techni-Tool - PN:488SO6775

Other solder tips

When stripping wire, only strip a tiny little bit of the insulation. Strip no more than a 1/32 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire than 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