Before First Power-On¶

Before connecting the My-Cloner to mains power for the first time, complete all checks on this page.

The goal is to confirm that the machine is mechanically complete, electrically safe and ready for its first controlled power-up.

Do Not Skip This Check

Do not connect the printer to mains power until all mechanical and electrical checks have been completed.

Mechanical Check¶

Confirm that the printer assembly is complete and that no parts are loose or obstructed.

Check the following:

All structural screws are installed and tightened.
The frame is stable and does not rock.
The X-axis moves freely from left to right.
The Y-axis moves freely forwards and backwards.
The Z-axis gantry can move vertically without binding.
Both Z lead screws rotate freely.
The belts are installed correctly.
The belts are tensioned but not excessively tight.
The extruder carriage moves freely.
The heated bed moves freely along the full Y-axis travel.
No cables interfere with moving parts.
No tools, screws, washers or loose parts remain inside the printer.

Move the Axes by Hand

With the printer powered off, gently move the X and Y axes by hand.

Movement should be smooth and should not require excessive force.

Heated Bed and Print Surface¶

Check the print bed assembly before powering the machine.

Confirm that:

The heated bed is securely mounted.
The bed wiring is not under tension.
The bed cables can move freely throughout the full Y-axis travel.
The magnetic surface is correctly installed.
The spring steel sheet sits flat on the bed.
The PEI surface is clean.
Any protective shipping film has been removed, if applicable.

Do not place tools or other objects on the print surface before the first homing procedure.

Hotend and Extruder Check¶

Inspect the complete extruder and hotend assembly.

Confirm that:

The hotend is securely mounted.
The nozzle is installed correctly.
The heater cartridge is secured inside the heater block.
The thermistor is secured correctly.
The hotend fan is installed.
The part-cooling fan is installed.
Fan cables cannot contact the heater block or nozzle.
The extruder motor is securely mounted.
The filament path is unobstructed.

Heater and Thermistor

A loose heater cartridge or thermistor can cause unsafe temperature readings or uncontrolled heating.

Do not power the printer if either component is loose or damaged.

Z Probe Check¶

The My-Cloner Rev A uses a P.I.N.D.A. probe.

Before first power-on, confirm that:

The probe is securely mounted.
The probe body is not damaged.
The probe cable is routed safely.
The cable does not interfere with X-axis movement.
The probe is positioned close to the nozzle height, according to the assembly instructions.

Do not perform automatic Z homing until the probe installation has been verified.

Filament Sensor Check¶

Check the filament sensor assembly.

Confirm that:

The sensor is securely installed.
The mechanical ball and magnet mechanism moves freely.
The filament path is unobstructed.
The sensor cable is correctly routed.
The cable cannot contact moving or hot components.

Wiring Check¶

Inspect all low-voltage wiring before connecting mains power.

Check every connection individually.

Confirm that:

All connectors are fully inserted.
No connector is installed at an angle.
No wires are loose inside screw terminals.
No bare copper is exposed outside terminals.
No wires are crushed by printed parts or frame components.
Cables are secured away from belts, rods, lead screws and fans.
Cable movement does not restrict any axis.

Pay particular attention to:

Mainboard power input
Heated bed power
Hotend heater
Hotend thermistor
Bed thermistor
Hotend fan
Part-cooling fan
Stepper motors
P.I.N.D.A. probe
Filament sensor
Raspberry Pi power wiring
LM2596 DC-DC converter

Check 24 V Polarity¶

The My-Cloner uses a 24 V DC electrical system.

Before power-up, verify the polarity of every DC power connection.

Check that:

Positive (+) terminals are connected to positive wiring.
Negative (-) terminals are connected to negative wiring.
The MKS Robin Nano V3 receives the correct polarity.
The heated bed receives the correct polarity.
The LM2596 input receives 24 V with the correct polarity.
The LM2596 output is connected correctly to the Raspberry Pi power input.

Reverse Polarity

Reverse polarity can permanently damage the mainboard, Raspberry Pi, DC-DC converter and other electronics.

Do not rely only on wire colour. Verify the actual connection path.

LM2596 Output Check¶

The Raspberry Pi Zero 2 W is powered through an LM2596 DC-DC converter.

Before connecting the LM2596 output to the Raspberry Pi, verify the converter output voltage.

The output must be set to approximately:

5 V DC

Check Before Connecting the Raspberry Pi

Do not connect the Raspberry Pi to an unverified LM2596 output.

An output voltage significantly above 5 V can damage the Raspberry Pi.

If the converter has not yet been adjusted, disconnect its output from the Raspberry Pi before the first electrical test.

Mainboard Check¶

Inspect the MKS Robin Nano V3.

Confirm that:

The board is securely mounted.
The board cannot contact conductive parts of the frame.
Power wiring is correctly connected.
Stepper motor connectors are correctly installed.
Heater and fan connections are secure.
Temperature sensors are connected.
The P.I.N.D.A. probe is connected to the intended input.
The filament sensor is connected correctly.
No loose screws or metal objects are near the board.

Raspberry Pi Check¶

Inspect the Raspberry Pi Zero 2 W installation.

Confirm that:

The Raspberry Pi is securely mounted.
The board cannot contact the metal frame.
The power connection is correct.
The connection between the Raspberry Pi and the MKS Robin Nano V3 is installed correctly.
No cable is under mechanical stress.

AC Input Check¶

The My-Cloner uses an IEC C14 mains inlet with an integrated switch and fuse.

Before connecting the printer to the wall outlet, confirm that:

The IEC inlet is securely installed.
The power switch operates correctly.
A suitable fuse is installed.
Live, neutral and protective earth conductors are correctly connected.
No mains conductor is exposed.
All mains connections are mechanically secure.
Protective earth is connected where required.
Mains wiring is physically separated from low-voltage wiring where possible.

Mains Voltage

AC mains voltage can cause serious injury or death.

Never work on mains wiring while the printer is connected to the power outlet.

If you are not qualified or confident working with mains voltage, have this section inspected by a qualified person.

Power Supply Check¶

The My-Cloner Rev A uses a:

Mean Well LRS-350-24

Before connecting the printer to mains power, inspect the power supply carefully.

Confirm that:

The PSU is securely mounted.
AC input wiring is correctly connected.
Protective earth is connected correctly.
24 V output wiring is correctly connected.
Terminal screws are tight.
No exposed conductor can contact the PSU enclosure.
Ventilation openings are not blocked.

Input Voltage Selector¶

The Mean Well LRS-350-24 includes an input voltage selector.

For operation on a 230 V mains supply, the selector must be set to the appropriate 230 V position.

Verify the Voltage Selector

Check the PSU voltage selector before connecting the printer to mains power.

An incorrect selector position may damage the power supply and connected electronics.

Fuse Check¶

Verify that the fuse installed in the IEC inlet matches the electrical design of the My-Cloner Rev A.

Check that:

The fuse is installed.
The fuse holder closes correctly.
The fuse is not visibly damaged.
The fuse rating matches the documented electrical specification.

Do not replace the fuse with a higher-rated fuse simply to prevent it from blowing.

A blown fuse indicates that the cause should be investigated.

Cable Management Check¶

Before first power-on, move every axis through its available travel by hand and observe the cables.

Confirm that:

No cable becomes tight.
No cable is pulled from a connector.
No cable enters a fan.
No cable touches the hotend.
No cable rubs against sharp edges.
No cable interferes with belts or lead screws.

Cable movement should remain controlled throughout the full motion range.

Final Visual Inspection¶

Perform one complete visual inspection of the printer.

Look for:

Loose screws
Loose connectors
Exposed copper
Damaged insulation
Pinched wires
Foreign metal objects
Missing components
Incorrect connector orientation
Tools left inside the printer
Anything that could obstruct movement

If something looks uncertain, correct it before continuing.

Pre-Power Checklist¶

Complete this checklist before connecting mains power.

Pre-Power Check Complete

If every item above has been verified, the My-Cloner is ready for its first controlled power-on.

Continue with:

First Power-On