Desktop Mill - Troubleshooting Guide

Introduction

The Haas Desktop Mill is the ultimate training machine for schools and technical colleges.

Powered by a full-function Haas CNC control housed in our portable simulator enclosure, the Desktop Mill is perfect for teaching the basic principles of programming and operating a CNC mill.

Designed to cut plastics and machinable wax, it is also perfect for hobbyists and benchtop machinists.

Symptom Table

Symptom	Possible Cause	Corrective Action
Alarm 4.992 S (SPINDLE) AMPLIFIER OVER CURRENT VFD Drive Error Code: SF1 Motor Short Circuit	Short-circuit or grounding at the drive output.	Refer to the VFD User Manual for the manufacturer's recommendations: Schneider Altivar 12 Users Manual
As the spindle comes to a stop, it starts spinning in the opposite direction. VFD display will flash and show outputs of 7Hz to 11Hz.	Incorrect parameters in VFD.	Correct the parameters. This only applies to Schneider VFDs. The VFD screen will show "rdy" when the machine is on. The VFD has a rotating button for menu navigation. Press the button to enter the menu system. Rotate the button to change your selection, then press it to confirm. Use the ESC button to move back up the menu tree. 1. Change the motor control type from PErF “Performance” to Std “Standard.” On the VFD select COnF -> FULL -> drC -> Ctt -> Std 2. Change to DC injection from Yes to No. On the VFD select COnF -> FULL -> FUn -> AdC -> AdC -> nO 3. Change deceleration from 1 sec to 1.5 sec. On the VFD, select COnF -> dEC -> set to 1.5
When trying to run the spindle at 10k rpm or higher, the VFD displays the OCF (overcurrent) error, and the NGC control generates alarms 4.9920 S (Spindle) Position Error too Large and 9146 Tabletop Driver Fault.	Incorrect parameters in VFD.	Change the Nominal Motor Speed. ConF -> FULL -> drC -> nSP -> set the value to “21.00” which represents 21000. (press down on the JOG Dial to confirm the value) This only applies to 120V Schneider VFDs.
Alarm 4.9920 S (Spindle) Position Error too Large is generated on startup and is resettable.	Software Error	Press the [RESET] button. Desktop Mill can then be used as usual.
Alarm 9142 Tabletop 24V Driver Power Supply Fault appears, followed by 9146 Tabletop Driver Fault, after attempting to run a program.	Outdated Firmware	The TT Firmware Version on the adapter board must be updated to MA.02.07. To locate its current version, select Diagnostics > System > Hardware. Instructions for updating the firmware can be found at I/O PCB, Regen Vector Drive, Auto Door Firmware - Update - NGC.
Alarm 9144 Tabletop Secondary Cable Disconnect appears after updating the software to 100.24.000.1200.	Outdated Firmware	The TT Firmware Version on the adapter board must be updated to MA.02.09. To locate its current version, select Diagnostics > System > Hardware. Instructions for updating the firmware can be found at I/O PCB, Regen Vector Drive, Auto Door Firmware - Update - NGC.
No axis load while the machine is in motion.	None	There is no force feedback from the axis motors or amplifiers to the control. Therefore, no axis load will show on the control. The machine is operating normally as intended.
Operating the spindle at low speeds is inaccurate and can also cause excessive overheating.	None	Running the spindle below 1500 RPM will result in excessive current being delivered to the integrated spindle motor, leading to failure. Update software to 100.24.000.1120 or higher. This will prevent any attempt to lower the spindle speed below 1500 rpm. HBC - 03-26-25
Attempting to command the spindle at a speed below its minimum allowed speed will cause Alarm 9192: Spindle Speed too Low.	None
The spindle activates when it is not commanded.	Outdated control parameters.	Update to the latest version of software and update configuration files.
The Estop button is released, but alarm 107 EMERGENCY STOP does not reset.	Estop cable has been disconnected.	Refer to the Estop and Alarm 107 Section below for the corrective action.
The spindle appears to move a reduced amount of its commanded distance.	Tampered dip switches.	Refer to the Reduced Axis Travel Section below for the corrective action.
Alarms 4.9911 AXIS AMPLIFIER CABLE DISCONNECTED and Alarm 9146 TABLETOP DRIVER FAULT are triggered after the spindle intermittently shuts off when commanded to run.	Spindle Motor Failure.	Refer to the Desktop Mill Spindle Resistance Test Section below for the corrective action.
Alarm 4.9146 S (SPINDLE) TABLETOP DRIVER FAULT, and the delta VFD shows the error message Lu5.	Incorrectly wired Delta VFD	The White and brown wires on 33-0546, labeled "RA" or "RB," are connected to terminal RA on the Delta VFD. It should be connected to "RB" even if the wire is labeled "RA". Go to AD0561 Desktop Mill - Variable Frequency Drive - Replacement for additional information on wiring the VFD.
Cannot reset settings 313, 314, or 315 (Max User Travel Limit X, Y, Z) after setting the value to less than 0.22. Alarm X.9107 Check your Home switch is generated when trying to reset the values for settings 313, 314, or 315.	An incorrect value entered in the settings caused a software error.	A software clean install is required. Contact your local Haas Factory Outlet.

Estop and Alarm 107

Possible Cause: The primary Estop cable [1] is disconnected from its port J9 [2] labeled "Estop SIM" on the table top adaptor.

Corrective Action:

If no parts are damaged, plug the cable back in and cycle power the machine.

If the cable [1] is damaged, replace the cable and power cycle the machine. P/N 33-0673

If the port [2] is damaged, replace the table top adaptor. P/N 93-32-3097

Reduced Axis Travel

Corrective Action: Dip Switches 1-4 on the stepper motor driver establish the step/revolution and must be changed to their correct configuration.

Switches 1-4 MUST be set as:

SW1 ON (down)

SW2 ON (down)

SW3 OFF (up)

SW4 ON (down)

Desktop Mill Spindle Resistance Test

Corrective Action: Use a multimeter to measure the resistance between the pins on the Desktop Mill Spindle.

Remove the Desktop Mill Spindle Power Cable.

Take the following resistance measurements on the spindle:

1 to 2.

1 to 3.

2 to 3.

Note: Resistance between each pin should be approximately the same value.

Note: If the resistance measurements between the pins are noticeably unequal, it indicates that the spindle must be replaced.

Important: In the case of a spindle replacement, machine software must be updated to version 100.24.000.1120 or higher. Please refer to the symptom table above for additional details regarding this update.