You should follow the link Randy gave you to isolate the motors, and give you a basic idea of what is involved. When I did this set I didn't even know TCS excisted. On the A unit I milled the rear top of frame for the decoder to sit in, IT WILL NOT FIT OTHERWISE BECAUSE OF THE CAB I also used the OEM bulb for the headlight. On the B unit they use the same frame as the a unit so the decoder can be mounted where the cab for the A unit would be. Good luck.
A UNIT
B UNIT
If it looks like this one, there's a bit of work involved, including milling of the frames.
http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/N_Scale/Bachmann/F7B/index.html
Doesn't look incredibly difficult, but clearly not just a case of soldering on some wires.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have a Bachman Spectrum N-scale F7 A-B set that I'm thinking about putting decoders in. These are the older type that ARE NOT "DCC frieldly". I have some questions:
1. Have I completely lost my mind?
2. Is there a step-by-step anywhere with photos?
3. Any advise from someone who has done this?
4. What kind of lighting did Prototype B-units have? The model has none, but somehow that doesn't seem likely.
Thanks...Mark Stewart