Conversion of older locos to DCC

[sxbiker]

I wonder if someone can help regarding the conversion of older locos to dcc operation. 

When choosing a decoder, I can find 2, 4 and 6 function items. Bearing in mind that my older locos are mainly steam (although I do have some Lima diesels) , will a 2 function decoder be sufficient?

Many thanks for your anticipated replies.

[Chrissaf]

...will a 2 function decoder be sufficient?

.

Yes

[ColinB]

I have done a load of my old locos and I must admit the two issues I had especialy with steam was "does the decoder fit in the space ?" and "what is the max current capacity of the motor drive, will this drive the motor in the loco ?".

Two function decoder means it will have functions to do forward lights and reverse lights. 4 functions means it has two additional functions for you to add such things as firebox light, cab lighting, smoke unit etc, 6 functions means it has two more functions (probably only any use on a diesel for different types of lighting). I found when converting mine it is a good idea to fit a socket rather than "hard wiring the decoder", that means you can easily convert it back to DC by changing the header, also it makes testing easier and gives you the option of fitting different DCC decoders later.

Be careful if you go for 6 pin decoders and you want to fit forward and reverse lights, although they have two functions the reference voltage to drive the lights does not come out on a pin.

[Rog RJ]

2 function decoders are a bit of a rarity now, most having more functions available.  If you are thinking of using the Bachmann 2 function decoder I suggest you don't as it's a very old design and IMHO should be avoided.  There are some 4 function decoders available that cost less and work much better.

[ColinB]

A lot of the 6 pin ones are 2 function, there are not enough pins for any more, although if you go to main circuit board sometimes there are pads you can solder to, if you are brave enough. The Hornby TTS decoders are actually 3 function. In a lot of the older locos I used 6 pins as there was very little space to fit an 8 pin socket.