FANUC SP9013 Alarm 13: CPU Internal RAM Error and Troubleshooting

FANUC SP9013 means that the spindle amplifier has detected an error in its CPU internal RAM. The related display on the spindle amplifier is alarm 13.

This alarm indicates an abnormality in the spindle amplifier control circuitry. FANUC troubleshooting guidance identifies the spindle amplifier as abnormal and specifies replacement of the spindle amplifier. Depending on the exact amplifier series and applicable maintenance manual, professional testing may identify the control printed-circuit board as the replaceable faulty component.

For the surrounding alarm numbers and their meanings, see the FANUC Serial Spindle Alarm Codes SP9001–SP9033.

Important: SP9013 Is a Spindle Amplifier Memory Fault

SP9013 is sometimes described as a “CNC data memory fault.” However, the FANUC maintenance manual defines amplifier alarm 13 more precisely as an error detected in the CPU internal RAM of the spindle amplifier.

This distinction is important. The alarm does not, by itself, indicate that the CNC program memory, SRAM backup data, machining programs, or CNC main board memory has failed. Troubleshooting should begin with the spindle amplifier identified by the alarm display.

1. Confirm the Alarm Information and Amplifier Model

Before replacing any hardware, record:

• The complete CNC alarm number: SP9013

• The spindle amplifier LED display: 13

• The exact FANUC spindle amplifier model

• When the alarm appears, especially whether it occurs immediately after power-on

• Whether the amplifier control board has recently been removed, replaced, or serviced

The applicable procedure can differ between spindle amplifier generations and maintenance-manual editions. Use the manual that corresponds to the exact amplifier installed in the machine.

2. Check the Installation of the Spindle Amplifier Control Board

As a preliminary hardware inspection, qualified maintenance personnel can confirm that the front control printed-circuit board is fully and correctly installed.

A poor connection between the control printed-circuit board and the power printed-circuit board may cause an amplifier to report an internal control-circuit abnormality. If the front board is visibly loose or was recently serviced, isolate the equipment according to the applicable FANUC safety and maintenance procedure, remove the board, and insert it fully and correctly.

This installation check is a practical preliminary step. The specific corrective action stated by FANUC for alarm code 13 in Maintenance Manual B-65285EN/04 is replacement of the abnormal spindle amplifier. Therefore, reseating the control board should not be presented as a confirmed repair when the alarm remains.

3. Test the Spindle Amplifier Control Printed-Circuit Board

If the control board is installed correctly but SP9013 remains, the CPU internal RAM or related control circuitry may be faulty.

Professionally test the spindle amplifier and its control printed-circuit board. On amplifier series for which the applicable FANUC documentation permits separate control-board replacement, replace the confirmed faulty control printed-circuit board and retest the amplifier.

Do not select a replacement board only by appearance. Confirm the exact spindle amplifier model, control-board part number, hardware specification, and applicable software requirements using the correct FANUC documentation.

4. Replace the Spindle Amplifier if the Alarm Remains

FANUC Maintenance Manual B-65285EN/04 states that when alarm code 13 is issued, the spindle amplifier is abnormal and should be replaced.

Replace the complete spindle amplifier when:

• The control board is correctly installed but alarm 13 remains

• The applicable manual specifies complete amplifier replacement

• A compatible control board is unavailable

• Professional testing confirms a fault that cannot be corrected by replacing the control board

• The replacement control board does not clear the alarm

After replacement, verify the machine using the commissioning and test procedures specified for the exact FANUC CNC and spindle amplifier configuration.

Difference Between Alarm 13 and Alarm 16

FANUC alarm codes 13 and 16 both involve CPU internal RAM, but they are not described identically:

Always use the number actually displayed by the spindle amplifier. Do not diagnose SP9013 as SP9016 unless the amplifier display confirms alarm 16.

FANUC SP9013 Diagnostic Table

Recommended Troubleshooting Order

1. Confirm SP9013 on the CNC and alarm 13 on the spindle amplifier.

2. Record the exact spindle amplifier model and control-board part number.

3. Check whether the front control printed-circuit board is fully and correctly installed.

4. If the board is loose, reinstall it according to the applicable FANUC maintenance procedure and retest.

5. If the alarm remains, professionally test the control board and spindle amplifier.

6. Replace the control board only when the exact compatible board and applicable replacement procedure have been confirmed.

7. Replace the complete spindle amplifier when required by the applicable manual or when the fault remains.

Unlike overcurrent or speed-deviation alarms, SP9013 does not direct technicians to spindle motor parameters, motor insulation, power cables, sensors, mechanical load, or PMC switching sequence. Avoid unrelated adjustments unless another alarm or test result provides evidence for them.

Technical References

• FANUC AC Servo Motor αis/αi Series, AC Spindle Motor αi Series, Servo Amplifier αi Series Maintenance Manual, B-65285EN/04, Alarm Code 13

• FANUC AC Servo Motor α Series, AC Spindle Motor α Series, Servo Amplifier α Series Maintenance Manual, B-65165 series, Alarm Code 13

Always use the maintenance-manual edition that applies to the exact spindle amplifier and machine configuration.

Need Help With FANUC SP9013 Alarm?

REACO CNC provides independent testing, repair, and replacement support for FANUC spindle amplifiers and control printed-circuit boards. Send us the CNC alarm screen, amplifier LED display, exact spindle amplifier model, control-board part number, and clear photos of the amplifier so our technicians can evaluate the fault.

Browse available FANUC servo, spindle, and power drives, learn about our FANUC and Mitsubishi CNC parts repair service, visit the FANUC Technical Support Center, or contact REACO CNC for assistance.

Reference Source: Beijing FANUC. This article is based on FANUC technical documentation. The applicable manual and replacement procedure depend on the exact CNC, spindle amplifier, control printed-circuit board, and machine configuration.