Fagor alarm 4138: ERROR 309: Short-circuit at the High Side IGBT
CNC 8055 SERCOS drive error (DDS) · Fagor DDS drives
What it means
Short-circuit detected on the high-side IGBT of the inverter/output stage. The drive cuts PWM (category 0 stop) and the CNC removes all enables and aborts every channel. Fagor documentation routes this straight to service: the power module is effectively destroyed.
Likely causes
- Failed high-side IGBT (shorted)
- Shoot-through caused by gate-driver failure
- Output short stressing the bridge
Triage note: On older XPS units this state is shown via front-panel LED combination instead of a numeric code.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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DDS / AXD / SPD drive (inverter stage)
drive · Common cause
Need the part urgently?
Send us alarm 4138 with your machine details — typical RFQ turnaround is 24–48h.