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That information doesn't seem to be public and available. However, this page:
says that the Reference Manual for the SX FA1 is available in the Download area, to Members. So becoming a member there might allow you to obtain the information, which may be in the Reference Manual.
Another Technics product, the SX-WSA1, is reported to have this reset:
- Turn the power off.
- Press and hold the "Real time Creator" ,  and  buttons while turning on the power.