Fault route
ZX7-160/200 Protection Light On Diagnostic
A small-inverter protection route for ZX7-160/200 machines.
Quick Answer
A protection light can be caused by real overheating, output short, MOSFET short, feedback abnormality or false protection input. Do not replace the control board before checking thermal switch, output path and power-device short evidence.
Diagnostic path
Thermal switch → output short → MOSFET/driver short → shunt/feedback path → control-board protection input.
Evidence table
Protection after power-on: check power-device/output short. Protection after load: check thermal path and output stage. Fan running but protection locked: feedback or protection input may be stuck.