Axis Servo Motor and Cables - Troubleshooting Guide

Electrical Safety

Caution: When you do maintenance or repair on CNC machines and their components, you must always follow basic safety precautions. This decreases the risk of injury and mechanical damage.

Set the main circuit breaker to the [OFF] position.

Danger: Before beginning any work inside the control cabinet the High Voltage indicator light on the 320V Power Supply / Vector Drive must have been off for at least 5 minutes.

Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not fully understand. If you have any doubts about doing a procedure contact your Haas Factory Outlet (HFO) and schedule a service visit.

Symptom Table

Symptom	Probable Cause	Corrective Action
Alarm 1.9918, 2.9918 or 3.9918 X , Y or Z AXIS SERIAL ENCODER INTERNAL DATA ERROR Alarm 1.9922, 2.9922 or 3.9922 X, Y or Z AXIS MOTION CHANNEL FAULT DETECTED Alarm 1.9923, 2.9923 or 3.9923 X, Y or Z AXIS SOFTWARE DETECTED ENCODER FAULT Alarm 1.9930, 2.9930 or 3.9930 X, Y or Z AXIS SERIAL ENCODER POOR COMMUNICATION Alarm 1.9959, 2.9959 or 3.9959 X, Y or Z AXIS SERIAL ENCODER DISCONNECT Alarm 1.9948, 2.9948 or 3.9948 X, Y or Z AXIS SECONDARY ENCODER SERIAL FAULT Alarm 1.9949, 2.9949 or 3.9949 X, Y or Z AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 1.9950, 2.9950 or 3.9950 X, Y or Z AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 1.9951, 2.9951 or 3.9951 X, Y or Z AXIS SECONDARY ENCODER SERIAL COMMUNICATION FAULT Alarm 1.9960, 2.9960 or 3.9960 X, Y or Z AXIS SECONDARY SERIAL ENCODER CABLE FAULT	The machine software is outdated.	Alarm is obsolete New alarm for encoder faults updated in software. Update to latest version 100.21.000.1130 or Higher; Added Alarms 9719 and 9720 for Encoder Fault Detection on Mocon Primary and Secondary Axes.
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x1) Encoder Data Fault = (Alarm 9918 SERIAL ENCODER INTERNAL DATA ERROR)	Encoder signals are affected by noise from high power cables. Faulty servo motor encoder.	Refer to Serial Data Communication Faults / Electrical Noise section below. Check the servo motor for coolant intrusion. For VMC machines, new servo motor cables can be ordered to mitigate coolant intrusion. See HBC-N 03-13-25.
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x2) Encoder Internal Axis Fault 1 = (Alarm 9922 MOTION CHANNEL FAULT DETECTED)	(The motion channel has reported an internal fault of a type that is not recognized by the control)	Cycle power to the machine. If the issue persists, take an error report (Shift F3) and email to Haas Service
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x3) Encoder Internal Axis Fault 2 = (Alarm 9923 SOFTWARE DETECTED ENCODER FAULT)	(Software has reported an internal fault of a type that is not recognized by the control.)	Cycle power to the machine. If the issue persists, take an error report (Shift F3) and email to Haas Service
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x4) Encoder CRC Fault = (Alarm 9930 SERIAL ENCODER POOR COMMUNICATION)	(Encoder signals are affected by noise from high power cables.)	(Refer to Serial Data Communication Faults / Electrical Noise section below.)
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x5) Encoder Cable Fault = (Alarm 9959 SERIAL ENCODER DISCONNECT)	(Cables are not connected correctly or encoder is faulty.)	(Inspect the cables and connectors. Refer to the Main Processor/Encoder Cable section below.)
Alarm 1.9720, 2.9720 or 3.9720 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x1) Encoder Data Fault = (Alarm 9948 SECONDARY ENCODER INTERNAL DATA ERROR)	Scale signals are affected by noise from high power cables. (Faulty Linear Scale, Configuration File issue; incorrect motor type or incorrect Scale type.)	Refer to Serial Data Communication Faults / Electrical Noise section below. (Check Scale Encoder for coolant contamination.)
Alarm 1.9720, 2.9720 or 3.9720 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x2) Encoder Internal Axis Fault 1 = (Alarm 9949 SOFTWARE DETECTED SECONDARY ENCODER FAULT)	(The motion channel has reported an internal fault of a type that is not recognized by the control)	Cycle power to the machine. If the issue persists, take an error report (Shift F3) and email Haas Service
Alarm 1.9720, 2.9720 or 3.9720 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x3) Encoder Internal Axis Fault 2 = (Alarm 9950 SOFTWARE DETECTED SECONDARY ENCODER FAULT)	(Software has reported an internal fault of a type that is not recognized by the control.)	Cycle power to the machine. If the issue persists, take an error report (Shift F3) and email to Haas Service
Alarm 1.9720, 2.9720 or 3.9720 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x4) Encoder CRC Fault = (Alarm 9951 SECONDARY ENCODER SERIAL COMMUNICATION FAULT )	(Liner Scale signals are affected by noise from high power cables.)	(Refer to Serial Data Communication Faults / Electrical Noise section below.)
Alarm 1.9719, 2.9719 or 3.9719 X, Y or Z AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x5) Encoder Cable Fault = (Alarm 9960 SECONDARY SERIAL ENCODER CABLE FAULT )	(Cables are not connected correctly or Linear scale is faulty.)	(Inspect the cables and connectors. Refer to the Main Processor/Encoder Cable section below.)
Alarms 1.161, 2.161, 3.161 X, Y or Z AXIS DRIVE FAULT	Faulty servo amplifier.	Check the corresponding amplifier assembly. Refer to Servo Amplifier - Troubleshooting Guide to troubleshoot the amplifier.
Alarm 1.217, 2.217, 3.217 X, Y or Z AXIS PHASING ERROR	Cables are not connected correctly	Inspect the cables and connectors. Refer to the Main Processor/Encoder Cable section below.
Alarm 1.217, 2.217, 3.217 X, Y or Z AXIS PHASING ERROR	The wrong type of motor has been installed.	Check that the correct motor type has been installed. (Sigma-5 or Sigma-7)
Alarm 1.645, 2.645, 3.645 X, Y or Z AXIS AMPLIFIER GROUND FAULT	Faulty power cable.	Inspect the cables and connectors. Refer to Power Cable section below.
	Faulty servo motor.	Check the corresponding servo motor. Refer to Servo Motor section below.
Alarm 1.993, 2.993, 3.993 X, Y or Z AXIS SHORT CIRCUIT	Faulty power cable.	Inspect the cables and connectors. Refer to Power Cable section below.
Alarm 1.993, 2.993, 3.993 X, Y or Z AXIS SHORT CIRCUIT	Faulty servo motor.	Check the corresponding servo motor. Refer to Servo Motor section below.
Alarm 1.103, 2.103, 3.103 X, Y or Z AXIS SERVO ERROR TOO LARGE Alarm 1.9920, 2.9920, 3.9920 X, Y or Z POSITION ERROR TOO LARGE	Encoder signals are affected by noise from high power cables. Or Faulty encoder.	Refer to Serial Data Communication Faults / Electrical Noise section below. Check the encoder steps/revolution versus and ball screw pitch and verify the encoder counts are accurate per each rotation.
	The axis motor brake, is not disengaging when servos are enabled.	See the Motor Brake section below:
	The axis ballscrew is damaged.	Check the corresponding axis ballscrew. Refer to Ballscrew - Troubleshooting Guide to troubleshoot the ballscrew.
	Faulty power cable.	Inspect the cables and connectors. Refer to Power Cable section below.
	Misaligned ballscrew coupling due to a crash	Verify that the ballscrew motor coupling is aligned refer to the Ballscrew - Troubleshooting Guide for further information on how to re-align the coupler NOTE: Verify that the power cable is not faulty prior to attemping to align the motor coupling.
Alarm 103 AXIS SERVO ERROR TOO LARGE, during the zero return process. The axis zero returns in the wrong direction.	The home sensor is being made during the zero return process causing the axis to zero return in the opposite direction.	Check the axis home switch to make sure there are no metal chips on top of the sensor.
Alarm 552 TRIPPED CIRCUIT BREAKER (on UMC-1000)	Damaged wire conduit and wires within conduit.	Remove back panel. Inspect wire conduit. If damaged, contact Haas Service Department for assistance.
The machine servos make a humming noise while sitting idle, jogging, or on a rapid.	The axis grid offset needs to be adjusted.	Perform the Axis Grid Offset adjustment procedure.
	The ballscrew is not aligned.	Verify that the ballscrew does not bind during travel and that it is correctly aligned.
	Outdated parameters.	Download the latest configuration files. If the axis servo continues to hum, contact your local HFO for more troubleshooting information.
Alarm 9804 240 VAC GROUND FAULT gets generated when I zero return an Axis.	There is a short circuit on the cable or motor.	Check for a short circuit on the corresponding servo motor and cable. Watch the Servo Power Cable and Motor Inspection Videos. Note: If alarm gets generated on a ST machine when the A-axis is zero returned the LT axis cable and motor must also be check for a short circuit condition.
Alarm 9804 240 VAC GROUND FAULT AND/OR Alarm 993 SHORT CIRCUIT AND/OR Alarm 103 AXIS SERVO ERROR TOO LARGE	There may be coolant intrusion on the axis servo motor.	Inspection the motor for coolant intrusion. For VMC machines, new servo motor cables can be ordered to mitigate coolant intrusion. See HBC-N 03-13-25. If motor is replaced because of coolant intrusion make sure to order the axis servo motor mount cover for motor mount that have a compatible motor mount cover. Refer to the VF/VR - X/Y Motor Mount Cover - Reference document to verify motor mounts and their covers. This document wil also have the part numbers for ordering.

Serial Data Communication Faults / Electrical Noise

Sigma-5 servo motors, non-contact encoders output serial data signal to the control. If the serial data signal is missing or becomes unreliable the control will generate a serial data communication error. Electrical noise can cause the serial data signal from the encoder to become unreliable and cause false alarms. Follow the troubleshooting guide below to help eliminate the noise in the system.

Incorrect machine grounding. Make sure the ground wire size is correct. Also the ground wire should run all the way back to the electrical panel.
Noise from other equipment. Make sure the machine does not share it's electrical service with another machine.
Loose encoder data connectors at PCB or at the motor encoder, can cause the serial data to become unreliable. Refer to the Main Processor / Encoder Cable section.
Loose ground or high voltage power connectors will induce noise into the system.
- electrical cabinet check for loose connection at all the ground and high voltage power terminals (vector drive, wye-delta contactors, transformer..etc).
- pendant check for loose terminal connectors.
- spindle head check for loose ground and motor power terminals.
The ferrite filters suppress high frequency noise produced by the amplifiers and vector drive, when servos are on. Make sure they are installed in:
- Encoder data cables. Make sure there is a ferrite filter P/N 64 1252 installed in all the encoder data cables.
- Axis motor power cables. Make sure there is a ferrite filter P/N 64-1252 installed in X, Y, Z axis motor power cables [1].
- Spindle motor cables. Make sure there is a ferrite filter installed in the motor output of the vector drive.
  For a 40HP vector with 6 wire leads [1] use ferrite P/N 64-1254.
  
  For a 40HP vector with 3 wire leads [2] use ferrite P/N 64-1252.
  
  For a 20HP vector drive with 6 or 3 wire leads [3, 4] use ferrite P/N 64-1252.
Cable routing. Make sure that the encoder cable is separated from high power spindle/axis/pump cables.

Maincon PCB / Encoder Cable

Corrective Action:

Examine the connector [1] on the Maincon. Make sure it is not damaged.

Examine the cable. Look for signs of damage or stiffness. The connector [4] has two housings [2,3] for the cable pins.

If the pins have been pushed into the motor, you must replace the motor and cable together.

Make sure the cable is firmly connected at both ends. Reseat both connections. Make sure the cable is installed in the correct connector at the Maincon or MOCON PCB.

Power Cable

Inspect the connector at the motor, look for loose connections between motor to cable or between cable spade terminals to amplifier. Check for connector contamination.

For VMC machines, new servo motor cables can be ordered to mitigate coolant intrusion. See HBC-N 03-13-25.

NOTE: Gently tug on the cables when checking for loose connection on the amplifier side. Pulling on the cables with excessive force can damage them.

Look for signs of damage and stiffness on the cable and connector. Disconnect the power cable from the amplifier and motor. Measure the resistance from leg to leg (red, white, black wires), and from leg to ground (green/yellow wire). Make sure the measurements result in an open connection. Refer to the table below as a reference.

NOTE: If the machine is experiencing intermittent short circuit alarms move the axis to the location where the cable would be most bent before performing this test. This may improve the likeliness of finding an intermittent short.

Servo Power Cable Wiring Reference Table
Function	Color	Motor End	Amplifiier End
Phase A	Red	A	Spade
Phase B	White	B	Spade
Phase C	Black	C	Spade
Chassis Ground	Green/Yellow	D	Ring
Braid	Braid	D	Not Connected

Perform a continuity test between the ground wire and the braided shield. If it fails the continuity test fails the cable shield is compromised.

NOTE: If the machine is experiencing intermittent short circuit alarms move the axis to the location where the cable would be most bent before performing this test. This may improve the likeliness of finding an intermittent short.

Check each leg from one end of the cable to the corresponding leg on the other end of the cable for continuity. Refer to the table above for wiring reference. If there is an open connection, there is a problem with the cable.

NOTE: If the machine is experiencing intermittent short circuit alarms move the axis to the location where the cable would be most bent before performing this test. This may improve the likeliness of finding an intermittent short.

Use the following troubleshooting chart to determine whether the motor, amp, or cable is defective.

When Alarm 993 SHORT CIRCUIT occurs disconnect the axis power cable from the motor. Press [RESET] and jog the axis.

If Alarm 103 AXIS SERVO ERROR TOO LARGE occurs then the motor is defective. If another Alarm 993 SHORT CIRCUIT occurs then the cable or amp is defective.

To determine if the cable or amp is defective disconnect the axis power cable from the motor and amp. Press [RESET] and jog the axis.

If Alarm 993 SHORT CIRCUIT generates then the amplifier is defective. If Alarm 103 AXIS SERVO ERROR TOO LARGE generates the cable is defective.

Servo Motor

Corrective Action:

Disconnect and inspect the power cable at the motor side. Verify the motor connectors are not contaminated, coolant contamination can generate drive fault alarms and damage the amplifier. Verify that the cable is connected to the corresponding amplifier as well.

For VMC machines, new servo motor cables can be ordered to mitigate coolant intrusion. See HBC-N 03-13-25.

Measure the resistance from the pins Labeled A, B, and C at the motor connector to the chassis ground.

The reading must show an open circuit
If the reading does not show an open circuit, the motor is at fault

Conduct a continuity test from the ground pin and chassis ground. The multimeter should beep or read less than 1 ohm resistance for continuity, otherwise then there is a short in the motor. Measure the resistance between the pins labeled A, B and C, refer to the table below for the resistance values.

NOTE: Nominal winding resistance has been added to the table for the 4-wire test method, when using a multimeter use the typical resistance value column for the expected values.

DC-1 30 Taper - Tool Carousel Motor without Brake

Important: Machines built before 3/1/2025 will have the motor without the brake.

The DC-1 tool carousel motor is a sigma7 size 04 motor. The pinout for the phases looks different than other axis motors.

This image shows the pins on the motor connector:

Gnd
Phase A
Phase B
Phase C

NOTE: The Gnd pin [1] should be longer than the other pins as shown in the image.

NOTE: Nominal winding resistance has been added to the table for the 4-wire test method, when using a multimeter use the typical resistance value column for the expected values.

Motor type	Haas PN	MPN	Motor size	Nominal winding resistance (Ohms)	Typical DMM measured winding resistance (Ohms)
Sigma 5	62-10011/ 62-10010	SGMGV-09ADA-HA11/ SGMGV-09ADA-HA21	9	0.894	0.9
	62-10013/ 62-10012	SGMGV-13ADA-HA11/ SGMGV-13ADA-HA21	13	0.554	0.6
	62-10015/ 62-10014	SGMGV-20ADA-HA11/ SGMGV-20ADA-HA21	20	0.291	0.4
	62-0101/ 62-10027	SGMSV-30ADV-YA11/ SGMSV-30ADA2E	30	0.179	0.3
Sigma 7	62-0127B	SGM7A-02AFK-HA21	2	6.5	6.6
	62-4445	SGM7A-04A7D61	4	4.3	4.2
	62-0117/ 62-0124	SGM7G-09AFA-HA11/ SGM7G-09AFA-HA21	9	0.882	1.0
	62-0119/ 62-0118	SGM7G-13AFA-HA11/ SGM7G-13AFA-HA21	13	0.557	0.6
	62-0120/ 62-0123	SGM7G-20AFA-HA11/ SGM7G-20AFA-HA21	20	0.286	0.4
	62-0122/ 62-0121	SGM7G-30AFB-HA11/ SGM7G-30AFB-HA21	30	0.177	0.2
Mitsubishi J5	62-0138/ 62-0141	HK-ST102WK-S101212/ HK-ST102WBK-S101212	9	1.254	1.4
	62-0137/ 62-0140	HK-ST172WK-S101212/ HK-ST172WBK-S101212	13	0.807	0.9
	62-0142/ 62-0139	HK-ST202AWK-S101212/ HK-ST202AWBK-S101212	20	0.558	0.7
Mitsubishi J3	62-0087/ 62-0088	HF-SP81MK-S12/ HF-SP81MBK-S12	9	1.149	1.4
	62-0089/ 62-0095	HF-SP131MK-S12/ HF-SP131MBK-S12	13	0.692	0.8
	62-0096/ 62-0097	HF-SP181MK-S12/ HF-SP181MBK-S12	20	0.456	0.5
Delta	62-0108/ 62-0109	ECMC-FW1308RS/ ECMC-FW1308SS	9	0.737	0.8

Motor Brake

Corrective Action:

Reseat the the connection for connectors P3, P4, or P5 on the I/O PCB.

Measure the voltage across the red and black cables.

Press [EMERGENCY STOP]. There should be no voltage.

Press [RESET] to clear the alarms. The voltage should be between 20-30 VDC.

Examine the connection at the motor's brake [2] and power connectors [3] for contamination. Reseat the connections.

If no voltage is present, refer to:

Next Generation Control - I/O PCB -Troubleshooting Guide