13.09.2025 by Viktor Siebert
Mitsubishi Servo Drive MR-S3-80BB-Z33 the Proven Reliability
The repair history of the Mitsubishi MR-S3-80BB-Z33 is a fine example of how expertise and a systematic approach lead to sustainable results.
The unit arrived from Greece, sent by a long-term customer. At first, it was unclear whether the fault was in the motors or in the drive itself. The customer swapped motors between identical machines, but the error remained the drive was identified as the source.
Upon arrival in our workshop, the MR-S3-80BB-Z33 showed signs of heavy use: dust, oil residues, discolored heatsinks. After documentation, we started the first test run. Axes one and three could be activated, axis two immediately triggered Alarm 32 (Overcurrent in power module).
We then measured the internal backup battery. The result: only 0.7 V, well below the expected value. It is important to note that this device does not indicate battery status by LED or display. The only way to check it is by direct voltage measurement. Therefore, a battery replacement was added to the repair process.
The device was cleaned thoroughly, electrolytic capacitors and relays replaced, solder joints reworked, and all connectors checked. Axis two was analyzed in detail, and a driver IC was found to show increased leakage current under load. Replacing this IC together with preventive replacements restored axis stability.
Extensive tests followed: long-term endurance cycles, thermal stress tests, current and voltage monitoring. After 24 hours of continuous operation, no further issues appeared. The drive was returned to the customer fully refurbished and ready for reliable operation for many more years.
To mentioned Mitsubishi Drive: Mitsubishi Servo Drive MR-S3-80BB-Z33
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Mitsubishi drive Repair by Industrypart
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Technical Specifications
| Item | Value |
|---|
| Model | MR-S3-80BB-Z33 |
| Axes | 3 |
| L-Axis capacity | approx. 1 kW |
| M-Axis capacity | 1 rank below L axis |
| S-Axis capacity | 1 rank below L axis |
| Weight | approx. 13.3 kg (29.25 lbs) |
| Boards | RF203C (control), RF23E (power), RF333C (auxiliary) |
| Power module | 80BB |
| Cooling | Fan-assisted |
| Option card | None |
Application Environment & Compatible Motors
The MR-S3-80BB-Z33 is typically used in machine tools and CNC machining centers. It is designed to operate with Mitsubishi HA-series servo motors such as HA80 or HA100. Its architecture ensures reliable axis control under demanding industrial conditions.
Functional Description
The drive controls three axes simultaneously. Separate control, power, and auxiliary boards make servicing and part replacement straightforward. Compared to older analog systems, the digital architecture improves repeatability, accuracy, and response.
Alarms & Troubleshooting
| Alarm | Cause | Remedy |
|---|
| 32 | Overcurrent in power module | Inspect/replace power module |
| 12 | Overtemperature | Check fans, clean airflow paths |
| 15 | DC-bus voltage error | Test capacitors |
| 22 | Excessive motor current | Inspect motor load and cables |
| 35 | Encoder signal error | Clean/replace encoder |
| 40 | Overspeed | Adjust parameters, reduce load |
| 51 | Phase error | Check wiring |
| 60 | Battery voltage low | Replace battery |
| 71 | Continuous overload | Adjust duty cycle, improve cooling |
| 99 | Control board fault | Test/replace control board |
Components
| Type | Model |
|---|
| Control board | RF203C |
| Power board | RF23E |
| Power module | 80BB |
| Auxiliary board | RF333C |