Bachman FP7-Bunit

Bachmann FP-7 b unit

T1 decoder installation

Pictures and text by Robert Lewis of Tilehust, Reading, United Kingdom
Picture FP-1. This is a Bachmann FP-7 B unit, it is totally standard. I have fitted a TCS-T1 decoder.
To remove the body remove the 2 crosshead screws between the bogies and the fuel tank, in the deep recesses. Also remove the 2 crosshead screws that hold the dummy fuel tank in place. The body should lift straight off.

Picture FP-2. The chassis is of the "live" type, where current is passed through the body from the bogie pick-up to the motor.
Disconnect the 2 black wires from the top motor contact, remove the crosshead screws from the top bogie mounts, the bogies can then be removed, the pick-up wire passes through a small hole in the casting. The motor can now be removed, it is only held in place by the grey packing foam. the motor can be a tight fit so a push from underneath maybe required.

Picture FP-3. To insulate the motor, and the brush contact from the chassis I have inserted 2 strips of plastic sheeting, cut from some packaging. I have also drilled a small hole to enable the fitting of a self tapping screw to hold a solder tag. Solder the Orange wire to one motor terminal and the the grey to the other. I have insulated and tied back the unused wires with rubber sleeving.

Picture FP-4. Using the original packing foam, push the motor back into the chassis, ensuring the plastic strips remain in place. Feed the black bogie pick-up wires back through the chassis holes and then re-fit the bogies and their retaining screws, do not over tighten these screws or the bogie will not be free to move.
Solder the red decoder wire to the solder tag and then screw to chassis. Join the 2 black pick-up wires to the black decoder wire, make sure this joint is well insulated. I have taped the decoder to the chassis. Now test the installation. Refit the body and fuel tank.