Polarity refers to DC power - one of the conductors is positive (+) one is negative (- or 'gnd' or 'ground' on the controller board). Steps where polarity is a consideration are noted - pay close attention and make sure that the positive and negative conductors are in the correct locations before applying power to the printer! Consequences of failing to observe polarity are expensive.
There are three motors that control the movement of the printer. The motors are identified as U, V and W. When looking at the front, the extruder drive (with the fourth motor) is at the back of the printer. The U motor is on the left front, the V motor is on the right front and the W motor is in the back center on the apex with the extruder drive.
The Athena Board has motor controllers and limit switches labeled for both Cartesian (x, y, z) and Delta (u, v, w) printers.
With the printer upside-down, mark the motors 'u', 'v' and 'w': The w-apex has the extruder drive attached to it; u-v-w are clockwise.
Loosen all of the screw terminals on the Athena Board and insert a small screwdriver into each terminal and wiggle it around to insure that it is fully open. This will greatly ease insertion of wires in later steps.
Affix heat sinks to motor controller chip
Remove the adhesive backing paper from the heat sink and affix the heat sink to only the chip on the motor controller boards. Note that the heat sink is NOT touching the soldered pins on the side of the board. There is the potential for a short circuit to occur if it is allowed to touch the pins - avoid this!
Note orientation of 1B, 1A, 2B, 2A labels.
Look at the back side of the motor controller and note the pins having the labels 1B, 1A, 2A, and 2B. These pins must be on the same side as the motor screw terminals on the Athena Board when inserted in their sockets.
Insert the motor controllers in their sockets. ORIENTATION MATTERS! Failure to properly orient the controllers can lead to destruction of the entire electronics package!
Recalling the pins having the labels 1B, 1A, 2A, 2B, insert the motor controllers so those pins are on the same side as the motor screw terminals. Failure to properly orient the motor controllers can lead to destruction of all of the electronics!
Insert the microSD card.
Insert the microSD card into the Orange Pi Zero, contacts go towards the board.
Press the Athena Board onto the Orange Pi.
Insert the pins on the Orange Pi into their mating sockets on the Athena Board. Only one orientation is possible, but it is possible to miss a pin on one end or the other. Assure all pins are in a socket! Damage to the Orange Pi can result if misaligned when power is applied.
Attach the Athena Board mount to the base in the orientation shown.
Refer to picture: With the four #6 x 1/2" sheet metal screws, attach the Athena Board mount to the underside of the base in the orientation shown - note location of the W motor (the motor on the apex having the extruder drive on it) with respect to the Athena Board Mount.
Attach Athena Board to mount.
Use the point of the precision knife to chamfer the holes in the mounting board before attaching the board. Attach the Athena Board to its mount using the four M3 x 6mm screws. A single orientation is possible.
Wire the hot end.
Insert the heater cartridge wires into the Heater1 screw terminal and tighten the screws; there is no polarity concern. Insert the thermistor wires into the Temp1 screw terminal and tighten the screws; polarity is not a concern.
Note the color of the wire attached to the red wire on the fan; this is the positive wire. Insert the positive wire into the right side of the Fan1 screw terminal and the other wire into the left and tighten the screws. Polarity matters!
Wire the Motors.
The motor wires must be correctly paired in the screw terminals; red-green must be in adjacent terminals and blue-yellow in the other two. Select an order (e.g., red-green-blue-yellow) and follow it with each of the motor screw terminals.
Wire the limit switches.
Note the color of the wires on each of the limit switches. Wire the U limit switch to the X/U limit switch screw terminal; V to the Y/V screw terminal, and W to the X/W terminal. There is no polarity concern.