This installation of TCS A4X digital decoder is for HO-Scale Atlas Alco C424 and was performed by A.G.
Please note: while this locomotive is manufactured by Atlas, the frame is made by Kato.
Here is the picture of the locomotive prior to the installation.
Remove both couplings by unscrewing a screw on both sides of the locomotive (Marked in red) and remove the shell by squeezing on either of the locomotive and rocking the shell back and forth until it lifts from the frame.
Here is a picture of the chassis with the original light board removed.
Next attach the red (orange) and the Black (gray) wire to the motor tabs as shown above. Make sure the tabs are not touching each other or decoder. Use Kapton tape if in doubt.
Place the A4X decoder on two plastic pins as shown above. Using the manual that came with the decoder, solder the red (orange) and Black (gray) motor wires to the decoder motor's pads.
As you see in the picture above, the front and the back of the locomotive was marked to make the installation easier. Using the manual that came with the decoder, solder the power pick up wires to the proper tabs of the decoder.
For this installation, we used 1.5 V surface mount LED with magnetic wire. Following the manual that came with the decoder, solder all LEDs to the proper 1.5V decoder's tabs. The red wire of the LED is a positive wire (+), and the green wire of the LED is the negative one(-). Make sure you are properly aware of the polarity so the LED will work.
Next we pointed each LED into the light tube and used electrical tape to hold it in place, as shown in the picture above.
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