I have a manual for the version that came with a D5 enlarger; I think the only difference is the power supply or "controller", which are interchangeable between heads (mine has the power supply and works with a separate timer). The head itself is actually fairly simple -- 24V DC at (IIRC) 10A required for the halogen lamp, 120VAC at low current for the fan and panel light. Color control is by cutting filters into the light before it enters the mixing box; this is a simple mechanical operation controlled directly by the setting wheels, with all filters dropped out by "white", and the "high" and "low" toggles in or out a metal mesh scrim of about 2 stops value -- useful mainly to get long enough exposures for manipulation and consistency without stopping the lens down past its optimum range.