18.05.2025 by Viktor Siebert

Background

The Mitsubishi MDS-C1-SPH-110 Spindle Drive Unit came to us already pre-repaired. The device had previously been with another repair service provider for nearly three weeks. It returned to the customer and only functioned for two days. When we received and inspected the device, we were also quite astonished. We have seen many things, but this repair was truly beyond comprehension.

The Initial Repair Attempt

Our customer reported finding a very affordable offer online. He quickly received a convincing callback from the provider, promising to repair the device in the shortest possible time. However, three days later, the customer received a quote that was more than 50% higher than originally promised: instead of 700 Euros, the offer was 1500 Euros. Even cleaning the device was listed separately. Additionally, the company charged 200 Euros for preparing the estimate in case of non-repair, something never mentioned previously.

The customer, grinding his teeth and lacking alternatives, accepted the offer, saving at least 300 Euros but compromising on the device’s appearance. After three weeks, he finally received the device, which was covered in dirt and oil. Nevertheless, he accepted it as it was cheaper.

Problems Post-Repair

After installation, the customer noticed that the device operated unusually loud but initially functioned. Just two days later, the device permanently failed due to an overload (Alarm AL32 – overload in the main power circuit). The customer had an external service provider check the wiring and motor and even temporarily replaced the spindle motor. Upon contacting the initial repair provider again, warranty claims were dismissed, and the provider demanded that both motor and drive be sent back for further inspection. Finally, the customer had enough and reached out to us.

Our Findings

Our technicians discovered the following severe issues:

• Electrolytic capacitors on the power board were incorrectly replaced: instead of the required 220 µF/50 V capacitors, 120 µF/50 V capacitors were used.
• Incorrect and used current measurement modules with incorrect ratings were installed.
• Used and excessively loud fans were installed.
• An incorrect transistor module rated at 100 A instead of the required 150 A was used. Although labeled “150 A,” it was a Chinese fake with re-labeled markings.
• The device had not been cleaned. It was extremely dirty, with oil and grime dripping from the heat sink.

Despite these major flaws, the previous technician had somehow managed to get the device briefly operational. However, it was obviously not a sustainable solution.

Our Professional Repair

We corrected all identified faults. The incorrect transistor module and presumably also the current measurement modules were the main culprits causing the issue this time. After our repair, the device was reinstalled a few weeks ago. Since then, it has been running smoothly, quietly, and reliably. The customer from France, who visited us personally, was extremely relieved and happy that this lengthy odyssey had finally reached a positive conclusion.

Conclusion and Recommendations

We regularly share cases like these and consistently encourage customers to opt for reputable and honest electronics repair alternatives. Always inquire thoroughly about the repair offer:

• What exactly will be repaired?
• How will the repair be performed?
• Are replacement parts genuinely available?
• Is there an option for replacement if the device is irreparable?
• What is the cost of preparing the estimate? Paying for it is acceptable, but customers should be informed in advance.
• Will the device be tested after the repair, and how?

Only through detailed information and trustworthy providers will you be satisfied long-term and retain confidence that reliable and honest companies still exist.

To mentioned Mitsubishi Drive: Mitsubishi MDS-C1-SPH-110 Spindle Drive Unit

More details about our Mitsubishi repair services can be found here:
Mitsubishi drive Repair by Industrypart

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Device Description and Technical Specifications

Feature	Value
Model	MDS-C1-SPH-110
Product Type	Spindle Drive Unit
Power	11 kW
Input	41 A, DC 270–311 V
Control Power	0.2 A, Single-phase, 200–230 V, 50/60 Hz
Output	37 A, 3-phase, 200 V, 0–833 Hz
Cooling	Air cooling
Manual Reference	BNP-C3000
Protection Standard	DIN VDE0160
Hardware Version	D
Weight	Approx. 11 kg (typical)

Operational Environment and Compatible Devices

Component	Description
CNC Controller	Compatible with Mitsubishi CNC controllers (e.g., MELDAS M60/M64/M65 series)
Power Supply Unit	Mitsubishi MDS-C1-CV series
Servo Drives	Mitsubishi MDS-series servo drives
Spindle Motors	Mitsubishi SJ-series spindle motors (e.g., SJ-11, SJ-V11)
Operating Temperature	0–55 °C (optimal performance up to 45 °C)
Humidity	10–90 % (non-condensing)
Mounting	Cabinet mounting with sufficient ventilation
Protection Class	IP20 (mounting inside an enclosure required)

Alarm Codes and Troubleshooting (Solutions)

Alarm Code	Description	Possible Causes	Recommended Actions
AL.12	Memory Error (SRAM/FROM checksum)	Internal memory error or disturbances	Restart the unit; replace if error persists
AL.16	Pole-position detection error	Encoder or wiring problem	Inspect feedback cables and encoder, replace if necessary
AL.18	Communication error with position sensor	Faulty wiring or defective position sensor	Inspect wiring and sensor, replace defective parts
AL.21	No signal from position sensor	Faulty or disconnected position sensor	Check and repair sensor and connections
AL.32	Overcurrent detected in power module	Short-circuit in wiring, motor, or drive unit	Inspect wiring and motor, replace faulty components