This installation of TCS A4X Decoder is for HO Scale Walthers Proto 1000 F3A and was performed by a TCS Customer.
Walthers did modelers a great favor by adding an NMRA 8-pin plug to the latest version of its HO scale Proto 1000 F3 locomotives. However, those of us with pre-Walthers F3s and a soldering phobia might still have our locos on the shelf.
It's time to bring those early issue P1K F3s into the DCC era using the Train Control Systems A4X decoder. It's an easy task.
After you get the body shell off, remove the two screws holding the factory circuit board in place, then detach the wires, saving the black plastic wire-retainer clips. Following the wiring diagram on the A4X instruction sheet, attach the loco wires to the proper nodes of the decoder using the black plastic clips.
Attach the wires of a new 14-volt, 30mA light bulb to the decoder in the same fashion. Yes, you'll be one plastic clip short; I ordered some extras from Walthers, but perhaps some liquid electrical tape will be enough to hold the wire in place (the light worked just fine during a test run with the second bulb wire just stuck through the hole, but it should be insulated to protect against shorting). Make sure you orient the A4X as shown in the photos or you'll wind up with a backup light like I did the first time.
Replace the body shell and the front coupler, and you're ready to roll. The P1K F3s fine mechanism runs even more smoothly under DCC control. The job is even simpler in the B unit, since there's no bulb to replace.
So there you have it — a brand-new TCS decoder in your early P1K F3 and not a soldering iron in sight!
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