This installation of TCS T1 Decoder is for HO Scale Wrenn Duchess Class LMS and was performed by Robert Lewis of Tilehust, Reading, United Kingdom

Important Soldering Tip:
Please do not use any flux either liquid or paste on the mother board. It will damage it. Use only Rosin core solder approved for electronics use.
We recommend to use only Kester "44" rosin core, SN63PB37, .015" diameter, part number 24-6337-0007.
This can be ordered from Techni-Tool under Techni-Tool part number 488SO157

This is a Wrenn locomotive of the City/Duchess Class of the LMS, it is a evolution of the original Hornby-Dublo 3 rail locomotive. The Wrenn model being of 2 rail type, with the wheels being isolated from each other (left & right side, unlike the 3 rail version), but this still leaves the metal chassis being live, directly connected to the left hand wheel set through the axles.

Picture Wrenn-1  To remove the body, un-screw the retaining screw located above the front pony truck.

Picture Wrenn-2 & 3   *  Important * ,  Both motor brush  sleeves must be isolated from the metal chassis. The brush holder (2) is factory fitted within an insulating sleeve. This arrangement has to be replicated with the other brush sleeve (3).  This can be achieved by purchasing an insulating sleeve from one of the many Wrenn spare suppliers in the UK. The component parts can be seen in picture 3, the insulating sleeve being the darker one.

To begin, remove the rear pony truck, the permanent magnet and the metal poles. Release the brass locknut and unscrew the top motor bearing, the commutator can now be removed.  The existing brush sleeve has to be removed, this can be done by passing a fine square ended punch through the insulated brush sleeve, and locating it on the edge of the un insulated sleeve, a few gentle taps with a hammer will push it through. the hole in the chassis has to be opened out to the match the outer diameter of the new insulating sleeve, this can be done with a drill or reamer. Care must be taken to ensure the hole remains in line with the opposite brush sleeve. The  new insulating sleeve can now be inserted, I placed a small drop of super glue (Cyanoacrylate) on the sleeve to ensure it remained in place. The original metal sleeve can then be inserted, ensuring there will be clearance between it and the commutator. Just to ensure insulation I used some transformer tape (yellow) on the exposed end of the metal sleeve. ensure to clean all swarf (filings) from the metal chassis, then reassemble the commutator and bearing, magnet and pony truck.
 Connect the red decoder wire to the solder tag (1) and the black to the wheel pick up wire (2). connect the grey wire to the front brush cap and the orange to the rear.
Test the installation before replacing the body. If all is ok the wires can be held in place with hot glue, I mounted the decoder vertically on its long side using hot glue in the area in front of the solder tag. Replace the body and securing screw.

While the locomotive was apart I also replaced the magnet with one of the Super Neo Magnets now available, it was a big improvement compared to the original steel magnet, which had lost most of its magnetism due to its age.

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

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