Introduction: Assemble HobbyCNC EZ Stepper Controller Board Kit

Build your own high-current 3-axis stepper motor controller board for your DIY robot, DIY mill or mill conversion, DIY router or anything else that needs to move. This is a build-it-yourself kit from

Step 1: Inspect the Components

Open the kit and verify all parts are present. It is recommended to use an ohmmeter to verify the resistor values.

Step 2: ​Insert (3) 10K Resistors.

Install (3) 10K (R1, R2, R3 Brown Black Black Red Brown) resistors. Simply bend the leads over to fit the PCB holes (typically .400”) and solder in. We ALWAYS use an Ohmmeter to verify values before soldering in place. It just takes a second or two but can save hours troubleshooting. Trim the leads.

Step 3: Install (2) 249R Resistors.

Install (2) 249R resistors (R4, R5 Red Yellow White Black Brown). Trim the leads.

Step 4: ​Install (1) 4.53K Resistor.

Install (1) 4.53K (R6 Yellow Green Orange Brown Brown) resistor. Trim the leads.

Step 5: ​Install (1) 750R Resistor.

Install (1) 750R (R7 Violet Green Black Black Brown) resistor. Trim the leads.

Step 6: ​Install (5) 0.1uF Capacitors

Install (5) 0.1uF (C1, C2, C3, C4, C5) Capacitors. These have NO orientation. Trim the leads.

Step 7: Insert (4) 10K Resistor Networks.

Solder in (4) 10K Resistor Networks (RN1, RN2, RN3, RN4). Orient the dot with the PCB silkscreened dot. Trim the leads.

Step 8: Insert (3) Capacitors 10uF 50V

Insert (3) Capacitors 10uF 50V (C6, C7, C8). Orient the longest lead into the hole marked “+”. The body has “-“ marked on it to help identify the proper orientation.

Step 9: ​Install (3) Potentiometers

Install (3) Potentiometers (VR1, VR2, VR3). They snap in place. Trim the leads.

Step 10: Install (3) 2 X 3 Pin Headers

Install (3) 2 X 3 (J1, J2, J3) Pin Headers. (Installing the Jumper/Shunts onto the longer pins makes holding them in place easier!) Refer to the PCB Connections drawing for proper orientation. Only 2 jumper shunts maximum are required for each 2 X 3 pin header to satisfy all stepping modes.

Step 11: Solder (P1) DB25 Male Connector

Solder (P1) DB25 Male connector in. Take your time as many pins are close together. We also solder the mounting lugs for an even more robust mounting.

Step 12: ​Install (4) 6 Position Terminal Blocks

Install (4) 6 Position Terminal Blocks (TB1, TB2, TB3, TB4). Orient the holes for the wires facing “out”. These may require a little extra heat to flow the solder as a lot of copper is present.

Step 13: Install (2) 2 Position Terminal Blocks

Install (2) 2 Position Terminal Blocks (TB5, TB6). Orient the holes facing the “plus and minus” signs. These may require a little extra heat to flow the solder as a lot of copper is present.

Step 14: Install (1) LM317HV

Install (1) LM317HV (U5), NOT the LM317. Orient the tab towards the broad white stripe. The PCB silkscreen shows this as a wide white band. Trim the leads.

Step 15: Install (1) LM317

Install (1) LM317 (U4). Orient the tab towards the broad white stripe. The PCB silkscreen shows this as a wide white band. Trim the leads.

Step 16: ​Install (2) 680uF Capacitors

Install (2) 680uF Capacitors (C9, C10). Orient the long lead into the hole marked “+”. Again the body is marked with “-“ to help with orientation. Trim the leads.

This completes the basic construction. DO NOT INSTALL U1, U2, and U3 UNTIL THE TEST IN THE NEXT STEP IS MADE!

Step 17: Test for +5VDC

To make sure no errors were made, apply at least 12VDC BUT less than 36VDC to TB5 labeled + and -.

Find an old 'wall wart' power supply (first image) or a bench power supply and jury-rig it to the board for this test. Exercise caution to ensure correct polarity to the board.

Verify that the proper testing voltage and polarity is present at TB5 (2nd image). Yes, this is one of the "Free with any purchase" Harbor Freight volt meters. It is perfect for this project and the cost can't be beat. In this example, the meter is set to 20 in the DCV section.

With a voltmeter verify that +5.0VDC to 5.2VDC is present at the pad labeled +5VDC. The black test lead touches the “-“ on TB5 (last image). If not, review all the above steps and correct them.

Failure to insure that +5.0VDC-+5.2VDC is present will BLOW the driver chips! (U4, R5, and R7 control the +5VDC voltage. These are the first items to check if the test fails!) Go no further until +5VDC is achieved with this test.

Step 18:

Install (3) 23 pin Driver Chips (U1, U2, U3, U4) only after the voltage test (step 17, above) is successful. Driver ICs can only go in one way.

If you are planning to use a heat sink, it is recommended insert the driver chips into the PC board, then attach the heat sink to the driver ICs before you solder the driver IC. This will minimize any stresses on the leads (which might lead to a long-term failure). Use thermal paste between each driver IC and the heatsink. Trim the leads.

Clean the PCB with alcohol or a flux remover and inspect all solder connections with a MAGNIFYING glass to assure against any solder bridges. These will cause ALMOST ALL failures!