22.10.2025 by Viktor Siebert
Repair of a Yaskawa SGDV-330A01A Servopack
Customer Issue Description
The customer reported that the Servopack turns off by itself, even when the machine is idle and no load is applied. No active error appeared on the display. The issue occurred intermittently, sometimes immediately after power-on. Logged alarms A.710, A.410, and A.EB1 pointed to unstable power supply and safety circuit interruptions.
Analysis and Diagnostics
During initial inspection, no external damage was visible. However, internal voltage measurements revealed unstable DC bus levels, especially during temperature variation.
Aging capacitors in the DC section showed reduced capacity, explaining the A.410 undervoltage and random resets. The A.EB1 safety alarm resulted from signal delays due to low control voltage stability.
The power board SGDV-CB330AAA exhibited high ESR readings on several points, indicating thermal fatigue. The cooling fan was clogged with dust and rotated slowly, which can trigger overload warnings (A.710) over time.
Repair Procedure
The Servopack was completely disassembled, cleaned ultrasonically, and dried. DC-bus capacitors, power semiconductors, and driver circuits were precisely tested.
All aging and stressed parts in the power and control sections were preventively replaced. The control board SGDV-IFA01B was tested, the 5 V supply stabilized, and safety input channels (/HWBB1, /HWBB2) re-soldered.
A full-load test was then performed on the Sigma-V test bench under multiple torque profiles. Thermal and voltage stability were restored, and no further resets occurred.
The fan was replaced with a new original unit. Isolation tests between power and logic circuits passed successfully. A final 12-hour burn-in at 230 V AC confirmed full stability.
Result and Preventive Measures
After repair, the Servopack functioned flawlessly.
Recommendations for long-term reliability:
- Replace fans every 2–3 years
- Check DC bus capacitors after 20 000 hours
- Maintain input voltage above 200 V AC
- Regularly verify safety signal synchronization
With these measures, the drive can operate safely and continuously without unexpected shutdowns.
Information about the mentioned Servopack: Yaskawa SGDV-330A01A Servopack
Further details on our Yaskawa repairs can be found here: Yaskawa Sigma V Repair
📞 Feel free to contact us if you have any questions regarding your Yaskawa drive technology. Our team will be happy to assist you.
Device Specifications
| Designation | Value |
|---|
| Model | SGDV-330A01A |
| Series | Sigma-V Servopack |
| AC Input | 3-phase 200–230 V AC 50/60 Hz |
| Input Current | 25 A |
| AC Output | 3-phase 0–230 V 0–400 Hz |
| Output Current | 32.9 A |
| Rated Power | 5 kW |
| Protection Class | IP10 |
| Ambient Temperature | 0–55 °C |
| Manufacturer | Yaskawa Electric Corporation, Japan |
Internal Components
| Name | PCB Designation | Quantity |
|---|
| Control Board | SGDV-IFA01B or 400-002-080-B0Y/B0Z | 1 |
| Power Board | SGDV-CB330AAA or 400-003-487-B0Z | 1 |
| Power Supply Board | SGDV-CC330AAA or 400-003-488-A1Z | 1 |
| Power Module | Complete assembly | 1 |
Logged Alarms and Meanings
| Code | Description | Meaning | Cause | Action |
|---|
| A.710 | Overload: High Load | Servo motor overload above nominal torque | Mechanical friction, wiring issue, axis blocked | Mechanical inspection, remove overload condition |
| A.410 | Undervoltage | DC bus voltage too low | Power drop, weak supply, blown fuse | Check input power, replace Servopack if needed |
| A.EB1 | Safety Signal Timing Error | Delay between /HWBB1 and /HWBB2 exceeds 10 s | Faulty safety input path, contact issue | Inspect and correct wiring and switching circuits |
| A.– | No alarm | Normal condition | – | – |