This installation is for a HO-Scale Walthers Proto 1000 R17 Subway Car using a TCS T4X Decoder and was performed by TCS.
HO-Scale Walthers Proto 1000 R17 Subway Car prior to T4X decoder installation.
In order to gain access to the factory light board for the T4X decoder install, first remove the four screws securing the car shell to the chassis.
One set of screws is marked with the red circles in the above picture. Once the screws are removed, carefully lift the shell off of the cars chassis.
With the shell now removed, we now have access to the facotry light board. Located in the center of the factory light board are pins 1 thru 8.
This is where we will make our decoder lead connection. Before we make any connections we must first cut the traces between pin 6 and 4, pin 2 and 5, and pin 1 and 8.
These points are all marked with a white "X". Make sure to cut through the trace completely, however, do remember the trace is very thin.
Use a dremel with a cut-off disk or hobby knife to split the trace.
The above picture shows the three points (X's) having been cut.
Next, remove the two screws securing the factory light board to the motor housing. With the light board flipped over, we now have access to the interior light bulbs (total of 2).
Since the traces these bulbs are tied into are track pick-ups, we must remove the bulb in order to be able to have control over them via the decoder.
First, desolder both leads of the bulb marked with the red circles in the above picture. Do this for the second bulb as well.
Note: The leads to these bulbs are delicate and can't be flexed too much.
With the bulbs removed, we can now solder our wire leads on.
In this install we are using function one to control the interior lights. This means we are using a green wire for our function output, while the blue is the common plus.
Cut about a 5"-6" piece of wire for each lead. Make sure to insulate your solder connections with 1/16" shrink tubing.
Now that the bulds have leads, we can now mount them back on the underside of the facotry light board. We used some medium CA glue for quick and easy adhesion.
With the bulbs wired and adhered, we can now wire our decoder to the factory light board.
P1: Orange, P2: Yellow, P3: Green(no connection) P4: Black, P5: Gray, P6: White, P7: Blue, and P8: Red.
Note: The green decoder lead will be used in the next step for the interior lights.
With the decoder wired, we can now screw the factory light board back down to the motor housing.
Next, we must wire our interior lights to the decoder. Marked with the red rectangles above are the function (green) and common plus (blue) wire connections.
With all our wire connections made, we can now neaten up our install. We used some kapton tape to clean up the wiring
and double sided foam tape to secure the decoder to the factory light board.
Finally, reattach the subway cars shell and reinstall the four screws.
You have now installed a TCS T4X decoder into your HO-Scale Walthers Proto 1000 R17 Subway Car.
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