Alarm guide · Yaskawa · Updated October 2026
Yaskawa A.830 alarm: absolute encoder battery error
Yaskawa A.830 is an absolute encoder battery error: the backup battery voltage is too low, so the encoder can lose its multi-turn position. Replace the battery and set the origin again.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
What the alarm means
The absolute encoder keeps its multi-turn position with a battery when the drive is off. A low battery, a loose battery connection or a cable fault raises this alarm. Alarm numbers and wording can differ between series, so confirm with the manual for your unit.
Common causes
- Battery low or exhausted
- Battery connector loose or missing
- Cable break between battery and encoder
- Encoder backup circuit fault
- Battery fitted after the position was already lost
Safe first checks
General guidance only. Follow the drive manual and your site's electrical safety rules. Power off, and let the DC bus discharge, before touching connectors.
- Note the exact alarm code and when it appears: at power-up, at start, or under load.
- Power off and turn the shaft by hand if safe: it should turn smoothly.
- Check the motor cable, encoder cable and connectors for damage and loose contacts.
- Check what changed recently: load, speed, settings, cables or a replaced part.
When to send it for repair
If a new battery does not clear it, the encoder or cable should be tested. Encoder alignment and multi-turn data setup is done on our bench.
We test every motor on our Universal Servo Motor Repair Equipment, which reads and aligns the feedback and runs the motor under load without the original drive.
See Yaskawa servo motor repair, Yaskawa encoder repair and Yaskawa servo drive repair.
Questions
Is my position lost?
It may be. After replacing the battery and clearing the encoder alarm, the machine origin usually has to be set again.
How long does repair take?
Emergency repair is done the same day where the fault and parts allow, urgent in 3 working days and standard in 7 working days, counted from when the unit reaches our bench and the quote is approved. Every unit returns with a printed test report.
Can I get an exchange unit?
If we hold a matching unit, Servo Swap ships a tested exchange unit while yours is repaired. Mark "line down" on the request form and add the part number.