Yaskawa GA800 A.124 Fault — What It Means
The code A.124 does not appear in available Yaskawa GA800 manufacturer documentation. Yaskawa GA800 drives typically display alarm codes in formats such as oC (overcurrent), Uv (undervoltage), oH (overheat), or CPFxx (control fault), not a dotted A.124 pattern. If you see A.124 on your keypad, it may be a misread display, a code from a different drive model, or a shop-specific label rather than the actual Yaskawa alarm name.
Because the exact meaning of A.124 is not verified in manufacturer sources, the correct first step is to confirm the precise alarm string shown on the drive’s keypad or control interface. Yaskawa GA800 drives store fault history and diagnostic data that can be accessed through the keypad monitor functions or via DriveWizard Industrial software. Once you identify the true alarm code, consult the GA800 technical manual troubleshooting section for that specific fault to determine the root cause, whether it is an output circuit issue, encoder problem, power supply fault, or control board failure.
Before You Replace Anything
Technicians sometimes replace the entire VFD or control board without first verifying the actual alarm code and checking motor cable integrity, encoder wiring, and incoming power supply. Always record the exact fault code and inspect wiring and connections before ordering expensive drive components.
Common Causes
- Misread or non-GA800 alarm code (~40%) The display may show a code from a different drive family, a third-party label, or a keypad misread that does not match Yaskawa GA800 factory alarm nomenclature.
- Overcurrent or output fault (~25%) If the true alarm is an overcurrent type, causes include motor cable shorts, damaged motor windings, or mechanical binding in the load.
- Encoder or PG option fault (~15%) Faults related to position feedback hardware can result from loose encoder wiring, a failed encoder, or a faulty PG option card.
- Incoming power or DC bus issue (~10%) Undervoltage or DC bus instability may trigger alarms if the supply voltage is out of specification or connections are poor.
- Control board or internal component failure (~10%) Persistent faults after wiring and load checks can point to damage on the drive’s control board, requiring board or drive replacement.
Quick Diagnosis
Answer these to narrow it down fast.
Does the keypad clearly show A.124, or could it be another alarm string (such as A124, A12.4, or a different format)?
No: Photograph the display and consult the GA800 alarm history function (accessible via keypad menu) to capture the true fault identifier before proceeding.
Has the drive been power-cycled or reset since the alarm appeared?
No: Check the fault history buffer before cycling power, because Yaskawa drives log multiple alarms and timestamps that help pinpoint intermittent issues.
Are there any visible signs of damage to motor cables, encoder cables, or drive terminals?
No: Use a multimeter to verify motor winding resistance and insulation to ground, and inspect encoder signal continuity if the drive uses feedback.
Step-by-Step Fix
- Confirm the exact alarm code by reading the drive keypad display carefully and accessing the fault history menu to capture the precise fault identifier and timestamp.
- Consult the GA800 technical manual alarm list for the verified code, and note the manufacturer’s troubleshooting procedure, affected subsystem, and recommended checks.
- Inspect motor and encoder wiring for shorts, opens, damaged insulation, and loose terminals, and measure motor winding resistance and insulation to ground with a megohmmeter if available.
- Check incoming power supply voltage and verify that all three phases (if applicable) are present and within the drive’s input specification range.
- Review drive parameter settings to make sure motor nameplate data, acceleration/deceleration times, and tuning values match the connected motor and load.
- Clear the fault according to the manual procedure (typically a dedicated reset input or keypad command) and attempt a test run under no-load or light-load conditions.
- Replace the identified failed component (motor, encoder, option card, or control board) if diagnostics confirm hardware damage, or contact Yaskawa technical support if the fault persists without a clear cause.
Parts Often Needed
| Part | Notes |
|---|---|
| Yaskawa GA800 control board | Amazon | Required if internal control circuitry is damaged and the drive cannot clear persistent faults after wiring and parameter checks. |
| Encoder or PG option card | Amazon | Replace if encoder feedback faults are confirmed and encoder wiring and motor-mounted encoder have been verified as intact. |
| Motor cable assembly | Amazon | Use shielded cable rated for VFD service if existing cable shows insulation damage, shorts, or excessive noise pickup. |
When to Call a Pro
Call a qualified industrial electrician or Yaskawa-certified technician if the alarm code cannot be identified in the manual, if the fault recurs after wiring and parameter corrections, or if you lack the tools to safely measure high-voltage DC bus, motor insulation, or encoder signals. Professional service is also required when the drive shows signs of internal board damage, such as burn marks, failed component startup, or alarms that persist across multiple power cycles with no external cause. Yaskawa technical support can provide remote diagnostics via DriveWizard Industrial and recommend whether board repair, drive replacement, or factory service is the most cost-effective solution for your specific GA800 model and application.
Rough cost: A pro service call runs about $200-800 depending on actual fault.