Schneider NHA37578 Terminal Board – Tested ATV340/930/960

When This Board Is the Suspect

• NST with wiring confirmed — the drive displays NST and refuses to start. Schneider’s official guidance lists two-wire vs. three-wire control configuration, freewheel stop terminal not connected to 24 V, and inverter lock assigned to a logic input as primary causes. 
• SPF after encoder checks — the drive reports speed feedback loss. Schneider’s SPF diagnostic points to the encoder feedback signal chain. 
• Control inputs not responding — start/stop or digital inputs are correctly wired and configured, but the drive does not respond. 
• Visible terminal damage — cracked housing, loose or stripped screws, or discoloration at the control terminal block.

Compatibility Check

Before ordering, confirm:

• Drive series — confirm the drive is ATV340, ATV930, or ATV960. This board is not for ATV61/71 or other platforms.
• Original board marking — confirm the existing board reads NHA37578.
• Terminal layout — compare the number and arrangement of control terminals against the original, especially the freewheel-stop and safety input positions.
• If unsure, send a photo of the original board label and the drive nameplate before purchase.

FAQ

Does NST always mean the terminal board is faulty?

No. NST indicates freewheel stop or no start command. Schneider lists two-wire/three-wire control configuration, freewheel-stop terminal not connected to 24 V, and inverter lock logic as primary causes. Check these first; inspect the signal board only if terminal wiring is confirmed correct.

What fault does SPF point to?

SPF is speed feedback loss, pointing to the encoder signal chain. The signal board hosts the encoder interface terminals, but the encoder itself, cable, and shielding are more common causes. Verify those first.

Is NHA37578 the main CPU board?

No. It is the control terminal and signal interface board. The main CPU board is a separate assembly.