Beginning old equipment at home (6)
I believe the answer is:
Here is my best explanation:
'beginning' is the definition.
(origin is a kind of beginning)
'old equipment at home' is the subsidiary indication.
'old' becomes 'o'.
'equipment' becomes 'rig' (rig is a kind of equipment).
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
(Other definitions for origin that I've seen before include "Point of creation", "spring", "Place where something begins", "Source, derivation", "Genesis", "Derivation", "For a start", "Where X meets Y", "Starting point or beginning" and "Source, root".)