How to Repin a CPC Connector — A Practical Guide for MultiCam CNC Machines

MultiCam CNC Tech Hub  |  CNC Maintenance  |  By George  |  12 June 2026

CPC (Circular Plastic Connector) connectors are used extensively on MultiCam USA CNC machines — primarily on stepper motor cables, but also on axis drive cables, brake connections and various other harness points throughout the machine. Over time the pins corrode, crack or fail at the crimp point, resulting in intermittent faults, axis errors or complete loss of drive on the affected axis.

The good news is that repinning a CPC connector is a repairable condition — you don't need to replace the entire cable harness. This guide walks through the complete process using Souriau-type male pins, applicable to any CPC connector on a MultiCam machine and to CPC connectors in general.

On MultiCam machines running the HP4 controller, CPC connector replacement is a particularly common requirement. The connectors on the HP4 control board are subjected to sustained heat over many years of operation — the plastic housing becomes brittle, discoloured and eventually cracks or burns through at the pin contacts. In these cases the connector body itself needs replacing rather than just the pins, but the repinning process is identical. If you are servicing an HP4 board, inspect all CPC connectors for heat discolouration and brittleness as a routine part of any HP4 reconditioning work — and check the HP80 stepper cards while the board is out.

Step 1 — Remove the Old Connector and Document the Wiring

Cut the old connector off the cable, leaving the pins inside the housing so you can see exactly which pin position corresponds to which wire colour. Cut approximately 100mm back from the connector end — this removes the section of wire most affected by oxidation and work-hardening near the old crimp points, and leaves enough wire length to clearly identify each colour.

Remove the strain relief (the rear section of the black CPC connector body). This will be reused — set it aside safely.

Old CPC connector with pins retained inside — cut approximately 100mm back from the connector end to expose clean wire and document wire colour positions before proceeding.

Step 2 — Prepare the Wires

Trim all wires to the same length. Strip approximately 5–8mm of PVC insulation from the end of each wire to suit the clamping section of the Souriau male pin. Twist the bare wire strands firmly to consolidate them — this prevents loose strands from shorting against adjacent pins once installed inside the connector.

Wires trimmed to equal length and stripped 5–8mm — ends twisted to consolidate strands.

Clean wire ends ready for pin crimping.

Before crimping any pins, slide a short length of heat shrink tube onto each wire. Do this now — it cannot be added after the pin is crimped.

Step 3 — Crimp the Pins

This is the most challenging part of the process. The Souriau crimping tool has a specific learning curve — budget time for this step and do not rush it. Destroying pins is an expensive mistake at over $1 each.

Pin components — male Souriau CPC pin, heat shrink tube pre-loaded on wire.

Crimping tool positioning — correct groove alignment is critical.

The correct crimping sequence is:

1. Place the pin into the crimping tool using the first groove as your locating position.
2. Gently close the tool to the prep position — just gripping the pin, not fully crimping. The pin must be correctly oriented in the slot (refer to photos).
3. Insert the stripped wire end into the pin until it bottoms out — approximately 5–8mm of insertion depth.
4. Close the tool fully to complete the crimp.

Correct pin placement at prep position — first groove located, tool just gripping, wire not yet inserted.

Wire inserted to full depth before completing the crimp.

Completed crimp — heat shrink tube positioned over crimped section only, not extending toward pin tip.

Once the pin is crimped and heat shrink applied, insert the pin into the correct position in the CPC connector body. The rear of the connector is marked with pin numbers — push each pin in firmly until it clicks into place.

Inserting crimped pin into correct numbered position in CPC connector body.

Pin clicked into position — all pins should protrude evenly and be relatively straight when viewed from the front.

Step 4 — Assembly and Final Check

Once all pins are inserted, inspect the front face of the connector. All pins should protrude to the same depth and be relatively straight. If any pin is shorter than the others or sits at an angle, grip the wire gently with long-nose pliers from behind and pull the pin forward until it clicks fully into its retaining position. Compare against a known-good connector if available.

Final Notes

Repinning a CPC connector is a methodical job that rewards patience and preparation. The sketch, the pre-loaded heat shrink, and the correct crimp tool positioning are what separate a reliable repair from one that fails again in the field. Done correctly, a repinned CPC connector is indistinguishable from new and will give years of reliable service.

This process applies equally to all CPC connectors regardless of machine or application. On MultiCam machines the most common repinning requirement is the stepper motor drive cables — typically presenting as an intermittent axis fault or complete loss of drive on one axis that cannot be resolved by adjusting the stepper card.