Step 18: Connect Galvos to Positive Power
Connect the negative speaker terminal (indicated with a "-") of the X galvo to the positive lead on your 12v power supply using 20 gauge hookup wire and your soldering iron.
Yes - to confirm -- we're connecting +12v to the negative speaker terminal .
Use ample wire for this connection (12 inches or more) - to assure you can position the galvos as needed later.
Repeat this step for the Y galvo.
Run a separate lead from each galvo back to the 12v power supply. Do not "chain" the connection between the two galvos.