A short tutorial on converting an 8-pin Hornby TTS Sound decoder for use with a Bachmann 21-pin locomotive, such as their Class 37 or Class 47.

While the majority of Heljan locomotives also come with a 21-pin DCC socket, it is recommended that you do not use a TTS decoder with their products given their higher current draw.

In the video, the 8-pin adaptors shown are made by LaisDCC and DCC Concepts. It is understood that Bachmann also make an adaptor. There may be others too.

Manufacturers have also produced different versions of the adaptor over the years, some of which come with AUX solder pads while others do not, so the manufacturer is not necessarily a guarantee of a particular design.

You can find the schematic in image form here: www.facebook.com/StrathpefferJunction/photos/a.2156466537917020.1073741829.2149839818579692/2162071747356499/

UPDATE: It is now possible to buy 21-Pin break out boards which, if used in place of the 8pin to 12pin adaptor, would negate the plug removal step, however they are currently more expensive per unit and often only come in packs of 5, so the method shown in the video is still the cheapest option.

Items required for this project are:

Hornby TTS Sound decoder
8-pin to 21-pin adaptor
Expo modelling saw
Soldering iron, solder & liquid flux (optional)
Various tools, including: jeweller's screwdrivers, small side cutters and an exacto knife and needle files.

You can buy a 5-pack of the 8-pin/21-pin adaptors here: https://amzn.to/2HzZ6Ik ...or buy a single 8-pin/21-pin adaptor here: https://amzn.to/2HF7Htc

Thank you very much for watching.

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