Whilst we crunch through a mound of unedited video filmed during June 2018, we thought we’d put out a short tutorial outlining one approach for making a custom 21-pin to 8-pin harness to enable the use of a 21-pin decoder in an 8-pin locomotive chassis.
The adaptor is simple to make and works well, but by its very nature, an 8-pin plug will not enable all functions of a 21-pin decoder to be used. This is unlikely to be an issue in most cases, as 8-pin chassis locos tend to have few built-in functions.
If used with a sound decoder, separate wires will need to be soldered to the adaptor for the speaker connections; the schematic below shows the relevant solder pads. Alternatively, in some cases, speaker wires can be soldered directly to the chip.
Download a free PDF file of the wiring diagram here:
Items required for this simple project are:
– MTC 21-pin breakout board (e.g. Laisdcc or ESU)
– 8-pin plug (pre-wired, if possible)
– Reel of decoder wire (for non-wired plugs)
– Soldering iron, solder & liquid flux
– Kapton tape or insulation tape
– Various tools, including: small side cutters, wire stripper and an exacto knife.