In short
Two related searches meet the same risk: fuse blows when plugged in or powered on and overvoltage protection trips (or the RCD / residual-current device trips). Both mean excess or fault current — often already at the input of the power supply board.
This is not harmless standby clicking. Re-applying power after a tripped fuse or RCD can worsen damage and fire risk. Unplug, find the cause — do not keep trying.
Fuse vs RCD vs surge protection
Device fuse F100 on the power supply board. Left, component side: 12.4 Ω, a poor contact from a dirty contact surface. Right, cross-check on the solder side: about 0 Ω (reading 0.5 Ω), i.e. continuity, so the fuse is fine. A defective fuse would show OL.
A device fuse on the power supply board or a house breaker protects against overcurrent. An RCD reacts to earth fault current. Surge protection (SPD / MOVs) can trip on mains spikes or fail short.
Note *which* protector trips and whether it already happens when the TV is plugged in or powered on. That drives triage — often the input stage of the power supply board. As a rule of thumb: if the house fuse trips as soon as the TV is plugged in or powered on, the cause is always the power supply board. Exceptions are possible. If in doubt, call in a TV technician.
- Fuse / RCD only when the TV is plugged in or powered on → device / power supply board first
- Several loads affected → more installation / surge event
- Burn smell, soot, bulged parts → do not keep running
- After lightning, dead set + tripped protection → have input/protection parts checked
Why often the power supply board?
The primary side of the power supply board has rectifiers, filters, fuses and protection parts. A short, failed MOV or punched-through capacitors can throw the house or device fuse immediately.
Related symptoms without an instant fuse trip: won't turn on, clicks twice, red LED blinking. Board swap: replace power supply board.
Safety notice
Lethal hazard. After a tripped fuse or RCD, do not re-energise “to test”. Discharge electrolytics before opening. The large electrolytic capacitors can hold up to about 400 V even after switching off: wait at least 2 hours, measure with a range of at least 600 V and only continue once the voltage is ideally below 30 V. Primary-side work is for specialists only.
Unsure? Leave it unplugged and book Repair.
What you can do (no live work)
Triage only:
- Unplug; check other loads on the same breaker
- External burn/melt marks on cable or chassis?
- Note model and board numbers — Find number
- Do not uprate the fuse or bypass the RCD
When AmparioWeb helps
With fuse / surge trips tied to the TV, inspecting the power supply board and a tested board swap often make sense. AmparioWeb supplies Parts and fixed-price Repair.
Frequently asked questions
- Replace the fuse and keep watching?
- Only after finding the cause. A new fuse that blows again confirms a short — take the set out of service.
- Is the RCD “too sensitive”?
- Sometimes an installation topic — but if only the LG OLED trips it, suspect the set first; do not disable the RCD.
- Can surge kill the power supply board?
- Yes. After spikes, input protection and the primary stage are typical victims.
- Panel or power supply board?
- Instant fuse/RCD trip when plugging in or powering on strongly points to the primary side of the power supply board, not the panel.
- Next step with AmparioWeb?
- Find number, then Repair or tested Parts.
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Power boards for LG OLED — tested under load, 12-month warranty.
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