The installation is for HO Scale Bachmann A1 steam locomotive Tornado. It uses TCS DP2X-UK digital decoder and was performed by Robert Lewis, UK.
The DP2X-UK decoder was used as its small decoder and fits easily into the space provided.
The decoder installation was performed before any of the extra detailing parts supplied in the box were fitted as these are quite fine and may easily be broken off during the handling required to disassemble the body. It is also worth considering oiling the locomotive while the body is off.
To remove the body, first remove the 2 crosshead screws under the cab end, and one screw at the front end, the pony truck will need to be pushed to one side to do this. Before lifting the body take note of the fine wire marked with the orange arrow, and the 3 positions it passes through on the locomotive body marked with the blue arrows, it is not "fixed" to the cab side, just passes through a hole, so it is ok to let is slide through the locating positions and let it be free to make the decoder installation easier.
The body seems to be a tight fit on the chassis, so a firm grip is required to lift it off, but once lifted need to be moved to the front of the chassis to let the wire mentioned above slide out of position.
The Bachmann blanking plug in position, also note the capacitor. Remove the plug by gently pulling straight up.
Before fitting the TCS decoder the capacitor will have to be bent gently as shown to allow clearance. The position of pin 1 of the TCS decoder is highlighted by the blue arrow. Test the locomotive before refitting the body, as its quite a delicate task to feed the fine piece of wire back through the 3 locating positions on the body, its not a procedure you will want to repeat if possible.
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 than a 1/32 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire than 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