In short
If the LG OLED standby LED is off and the TV won't turn on, the set often feels fully dead — no blink, no click, no remote response.
Classic power supply board suspicion: standby rail missing or start chain never begins. Not every dead set needs a new panel.
What “standby LED off” means
The standby LED sits at the bottom centre. Normally it lights red when the TV is off and goes out when you switch it on.
The standby LED normally shows that at least part of the supply is alive. Permanently off with the plug in often means the standby rail is already missing.
Contrast: red LED blinking, stays black, won't turn on.
- No LED after plugging in
- Remote and side button dead
- No relay click
- Sometimes brief LED after unplug, then dead again
Why often the power supply board
Many LG OLED power boards provide a standby voltage. If it fails, the LED stays off and the set never starts.
Mainboard faults can also darken the LED — triage still usually starts at the power supply board. See mainboard or power supply board.
Safety
Mains is lethal. Open chassis and power supply board = dangerous voltages. Discharge electrolytics. Never work live.
The large electrolytic capacitors can still hold up to about 400 V after switching off. After unplugging, wait at least 2 hours, measure with a range of at least 600 V and only continue once the voltage is below 30 V if possible.
Checks without voltage
Triage only:
- Other outlet / cable
- Document any brief LED (video)
- Model + board number — find number
- Recent surge/RCD trip — fuse/surge
When AmparioWeb helps
Standby LED off + won't turn on → power supply board/start-chain diagnosis before panel talk.
Frequently asked questions
- Dead panel if LED is off?
- Unlikely as first suspect. Missing standby often means power supply board.
- Vs blinking LED?
- Blink = fault report. Fully off = often no standby supply.
- Unplugging help?
- Sometimes briefly; if it returns → hardware.
- Which part first?
- No blind buy — find number.
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Power boards for LG OLED — tested under load, 12-month warranty.
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