Hold up... 8-pin means...

Dear Jeff,

Hold up a sec, an 8-pin connector is only capable of connectiing:

- Track IN (2 wires, Red and Black)
- Motor OUT (2 wires, Orange and Grey)
- Front Headlight OUT (1x Function F0f White)
- Rear Headlight OUT (1x Function F0r Yellow)
- "Function Common" (+ve volts)   (1x Blue wire)

Total : 7 wires/pins

Yes, that leaves 1x pin "spare", 
and some Decoder and Loco manufs have pressed that pin into active service,
against the NMRA spec
(The pin in meant to be left Deliberately Not-Connected,
so that if the 8-pin plug is plugged-in 180-degrees the wrong-way round,
the "Blue Function Common +ve Volts" is connected to Nothing,
and thus "fails safe")

but IIRC in the case of the "2nd run" B'mann Shays, the NMRA 8-pin wiring spec is respected,
and therefore, to wire-up a cab/firebox light will require Functions/Wiring in addition to the "standard 8-pin" wiring...

Said another way, I'm struggling to conceive how a "8-pin decoder" would have the ability to "run the cab light"...???

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Firebox light

I can tell you that the light in the cab is a firebox light, but not sure atm about how it is powered.   Waiting for a decoder I ordered to hook it up.

Ray

Prof K

Hmmm. In that case, perhaps it is rigged to always be on, or connected to F0 - both f & r?

Time to pull out the screwdriver and find out out, I guess. 

Firebox light - not controlled

In my Bachmann 3-Truck Shay the firebox light comes on as soon as the loco is moving - forward or reverse. It is not linked to the Headlight (F0) since the firebox light is on regardless of whether the Headlight is on or off, so I assume that there is some direct connection to the motor wiring.

I don't recall whether the firebox light worked before I fitted  the ESU LokSound Micro V4 decoder, but it is definitely not linked to any of the decoder functions.

I'm not sure whether I would recommend getting your screwdriver out just to satisfy idle curiosity - from personal experience, getting it all back together can be quite tricky (although not as difficult as the Bachmann Climax !)

Have fun . . .

. . .

Having three of these I can confirm the firebox flicker is taken from the DC going to motor. There is no cablight.

Getting control of the firebox flicker will require a tear down and re wiring the shay which is not a fun task.  IF you go this route, be careful not to pinch wires. :- ()  and blow a decoder ...don't ask. 

Marc

Thank you all.

I think I'm going to go with the 8-pin decoder I have for the time, and dream someday about a TSU-1100.