Ductless mini-split indoor head mounted high on a wall

Confirming an inverter board's DC bus is discharged before you touch it

Inverter boards store high-voltage DC in large capacitors after the power is off, and a dark LED does not mean the board is safe. Remove power, wait the maker's time, then measure the DC bus at the marked test points until it reads 0 V. Only then unplug loads or handle the board.

Cross-checked ~20 min moderateBrands: All

Before you start

Treat every inverter board as live until you have measured 0 V DC on the bus.
Do not short capacitors with a screwdriver; follow the maker's method if active discharge is required.

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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