# Help identifying Massoth XL wiring in LGB F7A?



## Jerry McColgan (Feb 8, 2008)

I installed this years ago in several LGB F7A See-Thru's and it works fine but I am intending to install several more of the same and I realized I do not understand the wiring.





































I have no idea why I have two whites, two yellow and two green wires going to the pins of the circuit board???

I also don't know why the circuit needs both the rainbow cable AND the wiring to the pins?

It seems that if the amps were not too low I could have used a Massoth L decoder and just plugged it in - as I have done with LGB's Mikados.

The Massoth L and LGB decoders were better for me because I did not have to understand anything.










Clearly I don't understand the circuits or use of non-LGB, non-Massoth decoders.

Jerry


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## Dan Pierce (Jan 2, 2008)

Jerry, LGB had 4 wires from each motor block and the colors are yellow, white, brown and green. So an F7 would have 2 sets of these.

The 6 pin cable has the V+, V+, V-, F1, front and rear light control.

Why 2 V+ are there is the LGB decoders had an adjustable voltage for front and rear light, and a second voltage source for F1 so you could have 5 volt lights and 18 volt light/smoke unit in an engine.


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## Jerry McColgan (Feb 8, 2008)

Dan Pierce said:


> Jerry, LGB had 4 wires from each motor block and the colors are yellow, white, brown and green. So an F7 would have 2 sets of these.
> 
> The 6 pin cable has the V+, V+, V-, F1, front and rear light control.
> 
> Why 2 V+ are there is the LGB decoders had an adjustable voltage for front and rear light, and a second voltage source for F1 so you could have 5 volt lights and 18 volt light/smoke unit in an engine.


Hi Dan,

That REALLY helps me a lot. I was confusing those 8 track & motor pins with the pins the L decoder plugs into.

Perhaps what puzzles me the most is the F1 pin. I don't recall any decoder other than LGB & Massoth having an F1 output. Is F1 not critical to having Serial (and even Parallel) operation?

I have used decoders like Digitrax and NEC that I simply wired for track and motor. I even have a DG583S that I set up years ago for an F7 that I did for a friend.

Clearly I have forgotten most of what I used yo know about MTS/DCC.

Jerry


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## Dan Pierce (Jan 2, 2008)

LGB used F1 output for smoke/lights but also the serial output for selecting different sounds.

Powered tenders with the 55021 used F1 for bell and whistle activation.


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