[mirage335]

tldr;
Connected the chair to power according to the third picture M_Bimmer posted, and also connected pin 1 to +12V.
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At last managed to get the time to try powering up the chair (some rather difficult things happened).

By connecting Pins 1, 15, to +12V, and connecting Pin 16, to GND, I was able to make some of the controls work.

Forward/Backward works.
Angle works.
Height down works.
Tilt forward works, but quickly ran to limit of its range - used to be click and motion, now just click.
Shoulders forward/backward works.
Thigh support forward/backward works.
Backrest width increase/decrease works.

Height up does NOT work - click and no motion.
Tilt backward does NOT work - no clicking noise.
Headrest up/down does NOT work - no clicking noise.
Curvature (all four controls) does NOT work, though significant power draw less than the 5A limit on this PSU is drawn - click, delay without motion, click.

Connecting to a much higher amperage power supply did not change these behaviors.


Hopefully, I just need to connect +12V/GND to more pins, or is the seat defective?