Cables needed for an LGB 'DCC Interface' to ESU decoder

[andyspencer]

Hi guys, just trying to work out what I need to connect up an LGB 21426 (GE 4/4 III). i thought i needed a 55026 cable, but is it the massoth 10way I need?

The box end:-

What does the little DCC symbol mean on the box?

And the instructions:-

Am I right in thinking that the 2 fat pins marked F2 and the 3way connecter marked F1/decoder+,- are duplicated from the 10 way connector?

Also the 2 pins marked sound - are these a constant voltage I could use to run pantograph motors and control aftermarket relays off the ESU chip or should I drive them straight from the chip? Further to earlier questions, this loco does not have factory fit powered pans.

 

[muns]

Hi Andy,
I believe the SND terminals will be connected to the track pickups (allowing the 65xxx that would be connected to them receive the DCC signals).

The 3 way connector and the F2 connectors will connect to your decoder via the 10way DCC connection.

 

[Cliff George]

I believe the SND terminals will be connected to the track pickups (allowing the 65xxx that would be connected to them receive the DCC signals).

Yes that is true, they can also be used to feed in more power to the LGB board and/or the decoder from say a tender.

The 3 way connector and the F2 connectors will connect to your decoder via the 10way DCC connection. (If this was from a loco so fitted of course!!)

No thats not quite true.

There is some extra electronics on the LGB interface board so that the F1 and F2 (and lights) functions from the decoder are decoupled from the F1 and F2 function outputs on the LGB board. The functions from the decoder just turn on the corresponding output on the interface board. This means that:

1) It doesn't matter what the voltage is on the decoder function outputs, F1 and F2 on the LGB interface board will always have 5v on them.
2) The power to supply the functions comes from the LGB interface board not the decoder.

F2 is indended for smoke units, while the F1 three way connector could be used for extra lights or other control functions. The new Massoth auto uncoupler can be connected there.

Possibly the F2 pins could be used for a constant voltage output that could control pantographs. Since they are designed for a smoke unit they will be able to supply quite a lot of power.

I know a lot of people often advocate ripping out LGB electronics when they put in a decoder. Sometimes that approach has merit, but personally if one of these LGB interface boards is fitted I'd tend to leave it there, because of the advantages listed above.

i thought i needed a 55026 cable, but is it the massoth 10way I need?

Correct, the LGB 55026 is the wrong cable, The Massoth 10 way DCC interface cable will work with an appropriate decoder. The LGB 55027 MTS III decoder comes ready fitted with the appropriate connector.

What does the little DCC symbol mean on the box?

It means the loco has a 'DCC Interface', the 10 way connector you have shown in your instructions picture