Schneider QGH43407_00 Trigger Board – ATV600/900 Power-Stage

When This Board Is the Suspect

• SCF (Short Circuit Fault) with motor cables disconnected — if the short-circuit fault remains after removing the motor leads, the issue is internal to the drive. An abnormal gate-drive signal from the trigger board is a documented contributor to SCF. 
• InF (Internal Fault) after control-to-power ribbon reseating — Schneider’s InF guidance for ATV600/900 platforms repeatedly points to ribbon connection between the control block and the power stage, as well as power-board feedback signal abnormality.
• No output / asymmetric phase behavior with IGBTs confirmed good — if the power modules test normal but the drive does not switch correctly, the gate-signal path on this board is the next suspect.

Compatibility Check

Before ordering, confirm:

• Drive MLFB — the exact ATV610/660/950/960/980 catalogue number on the nameplate. This board spans multiple platforms, but fitment and trigger topology can vary by frame size and power rating.
• Original board marking — confirm the existing board reads QGH43407_00. Do not substitute a different suffix without verifying the drive MLFB and the original label.
• Fault context — confirm SCF or InF persists after motor disconnection and ribbon reseating. If the fault clears, this board is likely not the root cause.
• If unsure, send a photo of the original board label and the drive nameplate before purchase.

FAQ

Is QGH43407_00 the main CPU control block?

No. It is the trigger / main board at the power-stage layer. The CPU control block for ATV600 is VX4B600100; for ATV900 it is VX4B900100. This board operates between the control block and the IGBT modules.

Does SCF always mean this trigger board is faulty?

No. SCF indicates a short-circuit condition. Motor cable insulation and IGBT module failure are common causes. A faulty trigger board is one possible source, but the motor and power modules should be ruled out first.

What does the “_00” suffix mean?

It is part of the part number QGH43407_00. Different suffixes may correspond to different hardware revisions. Verify the suffix on the original label before ordering.