Athearn SD75I Decoder Installation featuring the GEN-MB1 Motherboard with Keep Alive®, WOW121-Diesel Decoder, and 28mm Speaker by TCS.
First, remove the coupler box screws and the coupler boxes from both ends of the locomotive.
Next, remove the fuel tank cover by removing the single, centered screw on it.
Now, extract the two screws on either end of the fuel tank which you can see highlighted in red above.
With the couplers and under truck screws removed the shell should lift right off the chassis.
Remove the original lighting board from the chassis and remove the wires from the board tabs.
Next, we will prepare the speaker housing. Remove the screws holding the speaker in place.
Next, mount the 28mm Round WOWSpeaker facing into the speaker housing. This may seem counter-intuitive, but this permits the speaker wires to remain on the outside of the housing allowing for a solid seal all the way around.
Next, mount the GEN-MB1 on the motor just like the original lighting board and begin wiring it up according to the wiring diagram in your motherboard manual.
Solder in the lighting connections from the shell and install the WOW121-Decoder to complete the wiring of your installation.
Finally, you can replace the shell (it should slide over the installation easily), screw the shell in with the screws beneath the trucks, replace the fuel tank, and replace the couplers on the engine.
Your WOWSound equipped engine is now ready to run!
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 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