I know the topic has come up before about adding a sound decoder to a Bachmann DCC diesel, and the general concensus has been that it is difficult due to a lack of room in the A unit. What about adding sound to a FT-B unit and leaving the A unit alone? How much room is in a B unit? Has anyone done this, and if so- what parts were used?
Thanks
The A unit and B unit are almost exactly the same space-wise and it is just as difficult. What you need is an non-powered/dummy B unit to permanently latch to the A unit(s). This can be an old powered unit with the motor and other parts removed or a dummy with provisions to wire it for pickup, if permanently latched, the wires can go through to one of the A units.
To add to what AYC has said, a permanently coupled B-unit can take the power from the A-unit's wheels.
A B-unit with its own power pickup wheels can be used with any diesel locomotive by simply coupling it on and changing its address.
A B-unit with its own power pickup wheels can be permanently coupled to an A-unit AND wired to its pickup wheels, effectively doubling the number of pickup wheels.
And the unit with the sound built in can also be an A-unit if you want or have one available. You can also run a sound A-unit together with a powered B-unit if that works better for you.
Dummy units manufactured as dummy units rarely have power pickup wheels. But dummy units made from old powered units do have the necessary power pickups.
Jim