Emergency: same day
For a line-down motor, where the fault and parts allow. WhatsApp us before you send it so the bench is kept free.
Mitsubishi · OBA, OSA, OSE, OBE, OHE
Mitsubishi servo encoder repair: OBA13, OSA17, OBA18, OSA105 and more
Mitsubishi servo motors use serial encoders that report position and an encoder ID to MR-J series amplifiers. We test the count, ID and status, repair or replace the encoder, align it to the rotor and run the motor. Older incremental HA-series encoders are covered too.
Repair turnaround you can plan around
Send a photo of the nameplate first. We confirm whether the motor is repairable, and the quote, the same working day.
Urgent: 3 working days
Repair, encoder alignment and test, counted from the day the motor reaches the bench and the quote is approved.
Standard: 7 working days
Full repair, encoder alignment, run test under load and a printed test report.
- Free repairability check from a nameplate photo
- Printed test report with every motor
- Written warranty, terms stated on every quotation
- Pickup can be arranged; parts that must be imported are quoted with their own timeline
01Models
Encoder models we test, repair and replace
| Encoder | Counts per turn | Typical motors |
|---|---|---|
| OBE12 | 4,096 | Older serial motors |
| OBA13 | 8,192 | HC-MF and HC-KF small motors |
| OSA14, OAH14B | 16,384 | HC series |
| OHE4096 | 4,096 | HC series |
| OBA17, OSA17 | 131,072 | HC-MFS, HC-KFS, HC-SFS |
| OBA18, OSA18 | 262,144 | HC-MFS, HC-KFS, HC-SFS, HF-KP and HF-SP |
| OSA104, OSE104 | 1,048,576 (100,000 class) | HA and HC series |
| OSA105, OSE105, OSA105S2A | 1,048,576 (1,000,000 class) | HA and HC series |
| OSA253, OSE253 | 1,048,576 (25,000 class) | HA and HC series |
| OBA166, SBK2-2500 | Varies | Robot and special motors |
| OHE25K, OSE5K | ABZ with UVW | HA series incremental |
| Spindle ABZ sensors | ABZ | SJ spindle motors |
OSA253, OSA104 and OSA105 all report 20 bits; the 25,000, 100,000 and 1,000,000 figures are the resolution classes the drive uses.
02Faults
How these encoders usually fail
- AL.16 or AL.20 style encoder errors from board faults or water ingress
- Absolute position erased after a battery or cable fault
- Broken pins in small JST and AMP connectors on HC-MF and HC-KF motors
- Count errors from disc contamination
- Wrong encoder fitted, so the amplifier reads the wrong ID
03Identify
Reading the label
The encoder type is on its label under the rear cover. The motor nameplate, for example HC-SFS102, tells us the series and size; the amplifier reads the encoder ID to confirm the match.
04Motors
Motors fitted with these encoders
Mitsubishi HC-MF, HC-KF, HC-MFS, HC-KFS, HC-SFS, HC-RFS, HC-UFS, HC-PQ, HF-KP, HF-SP and HA series servo motors, SJ spindle motors, Mitsubishi robot axis motors.
05Service
What we do
Test and repair
Every check on the feedback test list, before and after repair.
Alignment
Commutation set to the rotor at every pole pair.
OpenMemory programming
Motor data written to a replacement encoder.
OpenReplacement
Matched encoder fitted, aligned and run tested.
Open06FAQ
Questions
Can you repair the encoder on an HC-KFS or HC-MFS motor?
Yes. These small motors often fail at the connector or encoder board. We repair or replace the encoder and align it.
What does AL.25 absolute position erased mean?
Usually the backup battery or its cable failed, so the multi-turn count was lost. Fix the battery, then re-home. If it returns, the encoder needs checking.
Do you handle newer HG series motors?
Send the model; we confirm the encoder type and approach before you ship.
Free downloads for your maintenance file
Printable one-page sheets from our bench. More on the resources page.
Servo motor encoder quick reference
Encoder families, interfaces, counts per revolution and the motors they sit on: Fanuc pulsecoders (alpha A64, A1000), Mitsubishi OBA/OSA, Yaskawa UTOPH, Tamagawa, Heidenhain ECN/EQN/ERN and SICK SKS/SRS/SRM.
PDF · 2 pages · 8 KB · free, no sign-up
Download PDFServo encoder alarm quick sheet
Common encoder and feedback alarms on Fanuc, Yaskawa, Mitsubishi and Siemens drives, what each usually points to, and what to check on the cable and connector first.
PDF · 1 page · 4 KB · free, no sign-up
Download PDF07Enquiry
Send the nameplate or encoder label
A clear photo of the motor nameplate and, if the cover is off, the encoder label is enough to start. We reply with whether it can be repaired and a quote.
Message received
Our team replies by email or WhatsApp, usually the same working day. For a line-down motor, WhatsApp +91 97866 22233.