This installation of TCS A6X digital decoder is for HO-Scale Atlas GP38 older verion and was performed by Craig Zeni.
The mechanism with the front weight and old decoder removed. The
weight must be removed to get the old decoder out and new decoder in.
At this point I tinned the wire ends on the locomotive.
The mechanism with the TCS A6X decoder installed and the wires soldered
in place. I use a 25 watt iron with a clean tip and a high quality
rosin core solder. Note that it may be necessary to *carefully* file
the mounting holes in the decoder to get it to slip over the plastic
clips on the mechanism. I had to square up the holes a little bit with
a square rat-tail file, taking great care not to damage any decoder
components or traces on the circuit board.
This photo shows both LEDs installed and the front weight fitted. Note
that the shell will not clear the rear light as shown here - the wiring
must be flush with the top of the weight. In the photos the resistors
are exposed so that the viewer can see what I have done. Before
finishing the project I will cover the resistors with heat shrink
tubing as seen on the LEDs.
The almost completed installation — the last step is the heat shrink
tubing for the resistors. Put the engine on the programming track to
make certain there are no shorts, program and enjoy the way the decoder
makes this engine perform.
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