EC/VC Rotary - Troubleshooting Guide

Introduction

The EC-400/500/630/1600 machines use hydraulics to actuate the rotary brake, pallet clamp, the pallet changer lift, and rotate system.

Pictured is the configuration for the EC-400/500/630. EC-1600's is configured differently. Please refer to the EC-1600 Rotary Troubleshooting Guide for further information on that style of rotary.

To troubleshoot the hydraulic power unit, please refer to the Hydraulic Power Unit Troubleshooting Guide for further information.

For related inspection reports, follow the link below. Be sure to download the correct inspection report for the correct machine. EA0419 for EC-400/500 and EA0429 for EC-500/50 and EC-630.

Inspection Report List

The accumulator sensor monitors the system pressure of the accumulator and this is what is shown on the controller under the diagnostics gauge page.

The accumulator is incorporated in the 4th axis brake and the pallet clamp and unclamp system but is not incorporated in the lift and rotate system.

This accumulator is meant to keep the pressure of the brake and clamp and unclamp system from dropping below a certain pressure threshold defined in Parameter 40.004 HPU 1 LOW HYDRAULIC PRESSURE THRESHOLD.

Symptom Table

Symptom	Possible Cause	Corrective Action
Alarm 6.108 B AXIS SERVO OVERLOAD	The feeds and speeds are too high for the work.	Decrease the feeds and speeds.
	The cutting tool is not sharp or is damaged.	Install a new tool or a new tool insert.
	There is a mechanical blockage in the axis of travel.	Make sure the axis has a clear path of travel.
	There is an internal mechanical obstruction in the rotary unit.	Test the rotary unit.
	The brake solenoid for the rotary unit has an electrical fault.	Troubleshoot the brake solenoid.
	The servo amplifier has a problem	Troubleshoot the servo amplifier.
Alarm 6.103 B AXIS SERVO ERROR TOO LARGE	The connection to the encoder or power is faulty.	Check the encoder and power cable connections to the motor.
	The rotary brake could be rusted to the platter.	Check for signs of corrosion or coolant intrusion.
	The input shaft on the Cycloidal unit is loose	Check for lateral and vertical movement of the input shaft. Verify the Lock Nut on input shaft has not come loose. See Input Shaft section.
Alarm 6.423 B AXIS SECONDARY ENCODER POSITION MISMATCH Alarm 6.9944 B AXIS SECONDARY ENCODER Z FAULT Alarm 6.9945 B AXIS SECONDARY ENCODER Z CHANNEL MISSING Alarm 6.9946 B AXIS SECONDARY ENCODER CABLE FAULT	The rotary scale or scale cable is faulty.	Check the rotary scale cable.
	The rotary scale encoder is not grounded correctly.	See B-Axis Rotary Scale Encoder section. HSG-N 02-24-2023
Alarm 6.9948 B AXIS SECONDARY ENCODER SERIAL FAULT Alarm 6.9918 B AXIS SERIAL ENCODER INTERNAL DATA ERROR Alarm 6.9922 B AXIS MOTION CHANNEL FAULT DETECTED Alarm 6.9923 B AXIS SOFTWARE DETECTED ENCODER FAULT Alarm 6.9930 B AXIS SERIAL ENCODER POOR COMMUNICATION Alarm 6.9959 B AXIS SERIAL ENCODER DISCONNECT Alarm 6.9949 B AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 6.9950 B AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 6.9951 B AXIS SECONDARY ENCODER SERIAL COMMUNICATION FAULT Alarm 6.9960 B AXIS SECONDARY SERIAL ENCODER CABLE FAULT	The 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 4011, 6.4011 ROTARY BRAKE ENGAGEMENT FAILURE	Air in the brake.	Bleed the brake.
	Pressure switch failure.	Check the pressure switch.
	Faulty solenoid.	Test the solenoid.
	Damaged brake booster seals.	Use the bleed tool kit to check for pressure.
	Air cylinder is seized.	Repair the cylinder shaft.
Backlash. Poor surface finish.	Air in the brake.	Bleed the brake.
	Faulty solenoid.	Test the solenoid.
	Damaged brake booster seals.	Use the bleed tool kit to check for pressure.
Alarm 4003 or 6.4003 Rotary Brake Release Failure	Pressure switch failure.	Check the pressure switch.
There is hydraulic oil leaking from below the platter or through the air blast.	One of the rotary union pallet clamp seals may be damaged.	Replace the pallet receiver and clamp assembly with the new version. Follow the link for further instructions. Pallet Receiver & Clamp Assembly EC-400/500 - Installation
Alarm 6.9719 B AXIS PRIMARY ENCODER SERIAL FAULT	There are 8 possible SubAlarms covered by the Serial Encoder Alarm. Alarm Subcode Subcode Meaning 1 Encoder Data Fault 2 Encoder Internal Axis Fault 1 3 Encoder Internal Axis Fault 2 4 Encoder CRC Fault 5 Encoder Cable Fault 6 Serial Stop Bit Error 7 Serial Parity Error 8 Encoder Counting Error	Contact Haas Service
Alarm 6.9720 B AXIS SECONDARY ENCODER SERIAL FAUL	There are 8 possible SubAlarms covered by the Serial Encoder Alarm. Alarm Subcode Subcode Meaning 1 Encoder Data Fault 2 Encoder Internal Axis Fault 1 3 Encoder Internal Axis Fault 2 4 Encoder CRC Fault 5 Encoder Cable Fault 6 Serial Stop Bit Error 7 Serial Parity Error 8 Encoder Counting Error	Contact Haas Service
EC-400/500 machines built between 01/19/2022 to 08/15/2025, exhibit corrosion-related degradation in the B-axis Rotary Brake or more components within the B-axis assembly.	Coolant intrusion has been identified at the B-axis clearance bleeder hole, suggesting a possible issue with sealing.	The B-axis platter must be replaced with the latest revision to prevent coolant intrusion and components that may have corroded may need to be replaced. Refer to the B-axis Pallet Receiver Coolant Intrusion section for detailed specifications.

B-Axis Rotary Scale Encoder

EC-400/500/630's are adding a ground wire to the 4th Axis rotary scale starting 3/2023. Inspect the B-axis ground cable that is attached to the encoder mount plate. Make sure it is fastened to the encoder mount plate. Verify the other end of the cable is connected to the chassis.

If the machine does not include a ground cable, please order the following part numbers:

EC-400/500:

33-8192 GND TO SP ENCODR 18.5FT (QTY: 1)
41-1610 PPHS 8-32 X 5/16 ZINC W/ EXT WASH (QTY: 1)

EC-630:

33-7325 CBL SP ENC GND 10-32 BOTH ENDS 29.0FT (QTY: 1)
41-1610 PPHS 8-32 X 5/16 ZINC W/ EXT WASH (QTY: 1)

Machines built after 1/2023 may have the updated read head mounting bracket already installed and will also need to order the following hardware to mount the ground wire. Please verify if the rotary unit has the dedicated ground wire hole [1] required.

40-1801 SHCS 8-32 X 3/8 (QTY: 1)
45-0159 WASHER #8 FLAT SAE .375 OD (QTY: 1)

Note: Do not loosen the read head screws, doing this will require the machine to be laser compensated.

If the machine does not have the dedicated hole, please use one of the cable clamp holes [2] to mount the ground wire.

The order in which the ground cable is mounted must be as follows; the ground cable mounted to the bracket, followed by the cable clamp, followed by a washer and finally the bolt.

Note: Do not loosen the read head screws. Doing this will require the machine to be laser compensated.

Input Shaft

Corrective Action:

Tighten the lock nut with the spanner wrench until the marks lined up.

B-axis Pallet Receiver Coolant Intrusion

Corrective Action:

IMPORTANT: EC-400/500 machines built between 01/19/2022 to 08/14/2025, that show signs of coolant intrusion, will require replacement of the B-axis Brake Housing Platter. As of 08/15/2025, there is a new version platter design (P/N: 20-7447C). This version features a spotface [2] at the bleeder hole to accommodate an O-ring (P/N: 57-0100) [1], which helps prevent corrosion caused by coolant ingress.

To add the O-ring (P/N: 57-0100) to the spotface on the B-axis Brake Housing Platter (P/N: 20-7447C), apply a uniform layer of silicone grease to O-ring [1] to ensure proper sealing and ease of installation.

Seat the lubricated O-ring into the designated spotface [2] on the platter, ensuring it is properly fully seated.

IMPORTANT: Contact Haas Service for more information on ordering replacement parts for corroded components in the B-axis Assembly. For more details on how to replace B-axis Brake Housing, refer to EC-400/500 Pallet Receiver and Clamp Assembly. Visit the EC-400 Rotary Brake Replacement for more information on how to replace the B-axis Rotary Brake.