Yaskawa GA800 VFD A.126 Fault — What It Means
The A.126 fault code does not appear in verified Yaskawa GA800 documentation as a standard alarm or fault identifier. GA800 drives typically display short alphanumeric codes on the keypad, and this particular code is not confirmed in manufacturer literature. The most likely explanations are a misread keypad display, a documentation or typing error, or a code from a different drive family or option card that does not map to the GA800’s published alarm list.
Because the code itself is unverified, the correct next step is to confirm the exact code displayed on the keypad before the drive was powered off, check the drive’s fault history using DriveWizard Industrial software if available, and consult the GA800 instruction manual or contact Yaskawa technical support with your full drive model number and the exact displayed characters. General troubleshooting for unrecognized or intermittent codes includes inspecting option cards, control wiring, and communication cables for loose connections or damage.
Before You Replace Anything
Technicians sometimes replace the main control board when the fault is actually caused by a poorly seated or damaged option card. Always de-energize the drive, reseat all option cards firmly, and verify wiring before ordering expensive control electronics.
Common Causes
- Misread or transient display code (~35%) The keypad may have shown a different code that was recorded incorrectly, or the fault cleared before the full code was noted.
- Poorly seated or faulty option card (~30%) Communication, encoder, or I/O option cards can generate non-standard fault codes if they are not fully inserted or have failed.
- Control wiring or communication cable issue (~20%) Loose, damaged, or incorrectly terminated control wiring can cause intermittent or unrecognized fault displays.
- Parameter configuration error (~10%) An incorrectly set parameter related to an option or communication protocol may trigger a fault that does not match standard alarm lists.
- Control board or firmware version mismatch (~5%) Older or updated firmware may display fault codes in a format that differs from the published manual for your drive revision.
Quick Diagnosis
Answer these to narrow it down fast.
Is the drive still displaying the A.126 code, or did it clear after a power cycle?
No: The fault was transient. Check the drive's fault history log to confirm the exact code and timestamp, then monitor for recurrence.
Are any option cards (communication, encoder, I/O) installed in the drive?
No: Skip option card checks and move to control wiring inspection and manual lookup.
Does your drive's instruction manual or parameter list show A.126 as a valid alarm or fault code?
No: Contact Yaskawa technical support with your full drive model number, serial number, firmware version, and the exact displayed code to confirm its meaning.
Step-by-Step Fix
- Confirm the exact displayed code on the keypad and write it down along with any additional text or symbols shown before powering off the drive.
- Check the drive’s fault history using the keypad menu or DriveWizard Industrial software to see if the code was logged with a timestamp and additional diagnostic data.
- De-energize the drive by switching off and locking out the main disconnect, then waiting for the DC bus capacitors to discharge completely.
- Inspect and reseat all option cards by removing each card, checking the connector pins for damage or debris, and firmly reseating each card until it clicks into place.
- Examine control wiring and communication cables for loose terminals, damaged insulation, or incorrect wire routing that could cause noise or intermittent faults.
- Consult the GA800 instruction manual for your specific model and firmware version to see if A.126 appears in the alarm or fault code table.
- Contact Yaskawa technical support with your drive’s full model number, serial number, firmware version, and the exact code display if the manual does not list A.126 or if the fault persists after reseating and wiring checks.
Parts Often Needed
| Part | Notes |
|---|---|
| Yaskawa GA800 option card (communication, encoder, or I/O) | Amazon | Only if the existing card is physically damaged or confirmed faulty by Yaskawa support. |
| Yaskawa GA800 control board | Amazon | Only after option cards, wiring, and parameter settings have been ruled out and Yaskawa support confirms board-level failure. |
When to Call a Pro
Call a qualified VFD technician or Yaskawa-authorized service provider if the exact meaning of A.126 cannot be confirmed in your manual, if the fault persists after reseating option cards and checking wiring, or if you are not trained to work safely on high-voltage industrial equipment. High-voltage VFDs require proper lockout/tagout procedures, knowledge of DC bus discharge times, and diagnostic tools such as DriveWizard Industrial software. Attempting repairs without this training can result in electric shock, equipment damage, or incorrect diagnosis that leads to unnecessary part replacement. A qualified technician can retrieve detailed fault logs, verify parameter settings, and coordinate with Yaskawa support to identify non-standard codes or firmware-specific issues.
Rough cost: A pro service call runs about $150-400 depending on diagnosis and travel.