Unplug the related connector and observe whether the protection light clears.
Fault route
LGK100L Power-On Protection Light Diagnostic
A board-level route for separating temperature relay, auxiliary rail, Hall feedback and main-control-board protection faults.
Quick Answer
For LGK100L power-on protection light, split the problem between temperature relay, control transformer rails, Hall sensor feedback and the main control board.
- If unplugging the temperature relay connector clears protection, inspect or replace the temperature relay.
- Check control-transformer secondary rails before replacing the main control board.
- If unplugging Hall sensor feedback clears protection, inspect Hall sensor and feedback wiring.
Use this page when
- Protection / abnormal indicator is ON after power-up.
- Fan/display behavior suggests the control section has some power.
- You can access control-board connectors for evidence checks.
Do not use this page when
- The machine is fully dead with no display and no fan.
- Input breaker trips immediately.
- The problem occurs only under cutting load after normal idle.
LGK100L protection-light route
Isolate thermal, auxiliary supply and feedback-protection evidence.
Check the listed secondary rail groups before board replacement.
Measure the Hall sensor supply and signal behavior at the control-board feedback connector.
Replace only after external protection inputs and rails are confirmed.
Measurement / evidence table
| Evidence point | Expected / abnormal evidence | Repair direction |
|---|---|---|
| Temperature relay connector | If protection light clears when unplugged, the thermal relay path is implicated. | Inspect/replace temperature relay or wiring. |
| Control-board supply connector | Reference rails include 0-27V-36V and 15V-0-15V groups in the source workflow. | If abnormal, check control transformer and secondary wiring. |
| Hall sensor feedback connector | Reference evidence includes DC15V, -DC15V and signal line behavior with no cutting command. | If abnormal, inspect Hall sensor and feedback wiring. |
| Main control board | If rails and external protection paths are normal but protection remains. | Main control board becomes the suspect. |