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Mitsubishi · OBA13
Mitsubishi OBA13 encoder repair, test and alignment
OBA13 is a Mitsubishi serial encoder with 8,192 counts. We test it, repair or replace it and align it to the rotor. Found on: HC-MF and HC-KF small servo motors. Star Automations is an independent multi-brand repair company and is not an OEM service centre.
- 25+years of servo repair, since 2000
- 3,000+customers across India
- 100+servo brands covered by our universal servo motor test equipment
- 5sites: Puducherry, Chennai, Bengaluru, Hyderabad, Delhi
- Same dayemergency repair option*
*Where the fault and parts allow. Every repaired unit returns with a printed test report.
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
01Facts
OBA13 at a glance
| Device | OBA13 |
|---|---|
| Brand family | Mitsubishi |
| Type and format | Mitsubishi serial |
| Counts | 8,192 |
| Found on | HC-MF and HC-KF small servo motors |
| Connector | Small multi-pin connector on the motor |
| Pole setting for alignment | Set at alignment |
The OBA13 is a small serial encoder at 8,192 counts per turn found on the HC-MF and HC-KF motors. It is a frequent repair because of its small connector and compact board.
02Faults
How OBA13 encoders usually fail
- Encoder communication alarm from a board fault or water ingress
- Absolute position erased after a battery or cable fault
- Broken pins in small connectors
- Count errors from a contaminated disc
- Wrong encoder fitted, so the amplifier reads the wrong ID
02+Alarms
OBA13 alarms and error codes: what they mean and what to check
These are the alarms most often seen with the OBA13 feedback device, with what each usually means and what to check first. Many encoder alarms are caused by the cable, connector or battery, not the encoder, so the checks below can save a repair.
| Alarm | Usually means | Check first |
|---|---|---|
| AL.16 | The amplifier cannot read the encoder at power-up (initial communication error) | Cable and connector at both ends, encoder supply, then the encoder board |
| AL.17 | Amplifier board error, found on the amplifier rather than the encoder | Test the amplifier with a known-good motor before blaming the encoder |
| AL.1A | Motor and amplifier combination error | Check the motor type against the amplifier; after an encoder change, check the new encoder identifies as the right type |
| AL.20 | Communication with the encoder fails while the axis is running | Cable flexing, noise, connector, then the encoder board |
| AL.21 | Second encoder communication error, bad data received (MR-J3 and later) | Treat as AL.20: noise and cable first, then the encoder |
| AL.25 | Absolute position lost | Battery and battery cable, then home the axis again |
| AL.92 | Warning: battery cable open or battery voltage falling | Check the battery cable and connector, replace the battery soon |
| AL.9F | Warning: battery voltage low | Replace the battery with the amplifier control power on |
| AL.E3 | Warning: absolute position counter (multi-turn count) problem | Check the battery and encoder, then set the home position again |
| AL.52 | Error excessive: the axis does not follow the command | Can come from lost encoder counts or a wrong encoder direction; check the encoder signal, then the mechanics and gains |
Older MR-J2 amplifiers word AL.16 and AL.20 as encoder error 1 and 2; the numbers stay the same. Alarm numbers and wording change with drive series and firmware, so check the manual for your drive. Drive brand names are used only to identify alarm lists. Star Automations is an independent multi-brand repair company and is not an OEM service centre.
Typical causes and checks
- Alarm at every power-up: reseat the connector at both ends, check the encoder supply at the motor end, and look for a broken wire.
- Alarm only when the axis moves or the cable flexes: suspect a break inside the cable chain, or a shield that has come loose.
- Alarm after coolant, washdown or rain: look for moisture or corrosion in the connector and behind the encoder cover.
- Alarm at random with other drives running: check earthing and shield clamps, and keep the feedback cable away from power cables.
- Position lost after a long stop or battery change: check battery voltage and the battery cable before suspecting the encoder.
- Alarm after a motor, encoder or drive change: check the type, the motor data in the drive, and the encoder alignment, then set the reference position again.
Encoder, cable or drive?
Swap in a known-good feedback cable first. If the alarm stays, move the motor to another axis if the drives are the same type. If the alarm follows the motor, the encoder or motor needs testing. If it stays on the axis with a good motor and cable, the drive needs testing. We test the encoder, the motor and the drive, so send the nameplate if you are not sure which it is.
Related guides: Mitsubishi AL.16 / AL.20 alarm, Servo encoder alarms, Absolute encoder battery.
03Process
How the repair is done
Receive and identify
We read the nameplate and encoder label and confirm the exact type.
Test
Count per turn, data status, alarm flags and, where fitted, incremental lines are checked on the bench.
Repair or replace
Board, connector or sensor faults are repaired; a matched encoder is fitted where repair is not sensible.
Align
Commutation is set to the rotor and checked at every pole pair using the electrical angle.
Verify and report
The motor is run on the bench and the readings are recorded in the report.
See encoder alignment, memory programming and replacement.
05FAQ
Questions
What do encoder alarms on a OBA13 usually mean?
Most fall into four groups: no communication, corrupted data, a fault reported by the encoder itself, and lost battery backup or position. The alarm table on this page lists the common codes and the first check for each.
How can I tell whether the OBA13 encoder, the cable or the drive is at fault?
Swap in a known-good feedback cable, then move the motor to another axis if possible. If the alarm follows the motor, the encoder needs testing; if it stays on the axis, the drive does. A cable or battery fault can be fixed without sending anything.
Can you repair a OBA13 encoder?
Yes. We test the position count and status, repair or replace the encoder, align it to the rotor and run the motor. We repair Mitsubishi units; Star Automations is an independent multi-brand repair company and is not an OEM service centre.
What motors use the OBA13 encoder?
HC-MF and HC-KF small motors.
What does AL.16 or AL.20 mean on this motor?
An encoder communication error. The usual causes are the cable, the connector or the encoder board; we test the encoder on the bench to tell which.
What should I send for a OBA13 enquiry?
A clear photo of the motor nameplate and, if the cover is off, the encoder label. You can send the motor or only the encoder.
06Enquiry
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.
→How it works
From nameplate photo to a tested motor in 7 steps
One route for servo motors, encoders and drives. You see the price before any work starts, and the report before the unit leaves our bench.
- 1 · Nameplate photoSend it on WhatsApp or the form
- 2 · Repairable? QuoteUsually the same working day
- 3 · Courier or pickupThe unit reaches our bench
- 4 · Bench diagnosisInsulation, windings, brake, encoder
- 5 · RepairFailed parts, bearings, seals, brake
- 6 · Align and run-testEncoder aligned; no-load and load run
- 7 · Report and dispatchPrinted test report with the unit
- Line down?Servo Swap ships a tested unit first. How Servo Swap works
EmergencySame day*
Urgent3 working days
Standard7 working days
*Where the fault and parts allow. Turnaround counts from when the unit reaches our bench and the quote is approved.