These ER sets would have one DMCL from diagram 559 and one from diagram 580 (the difference being one had a smoking first class section, the other was non-smoking), a TSL from diagram 583 and TBSL from diagram 584:
These are from the Derby Works Collection:
Single Engine Conversion
3-car diagrams & Works Pics
2-car diagrams & Drivers Instructions
4-car diagrams & Works Pics
Details about preserved Class 104s can be found here.
Many thanks to Kevin Dowd for his assistance in the preparation of these pages.