Some notes on the Microbot Alpha II (or 'Teachmover') robot arm.

The base of the arm contains one PCB, marked “Microbot Inc. Alpha Motor Drive Assy: 10131 Rev A” (serial 636). It contains 12 single-phase stepper drivers (a combination of RIFA and ST PBL3717 ICs), as well as two LM339N quad comparator ICs.

The PBL3717 drivers can output 5-1200mA per phase at 10-50v, with 5v logic, and rather than 'typical' step/dir control, they have a 'phase' and two-pin selectable current level input. They are capable of full or half stepping.

SW4 is unused

Source: http://doks.khk.be/eindwerk/do/files/FiSe413ebf17fb06726200fb06bc9787159b/eindwerk2004178.pdf

Power socket pinout, as seen facing the board

                       
 |          _______         |  | | |
 |         |       |        |1 | | |
 |         | o   o | +5v    |0 | | |
 |         |       |        |0 | | |
 |     RST | o   o |        |µ | |_|
 |         |       |        |F |
 | +VMotor | o   o | GND    |  |
 |         |_______|        |__|
 |
 |__________________________________
    \___________________________/
          DB-50 Connector