中文
含义
电视电源板（PSU）输出电压异常，电视无法正常供电或自动关机。E7 表示电视主板检测到来自电源板的某一路或多路供电电压偏离正常范围。
常见原因
- PFC（功率因数校正）电路故障，380V 直流母线电压无法建立或偏低。
- 主开关电源变压器初级绕组匝间短路，电源进入过流保护。
- 电源板输出端整流二极管或滤波电容失效，导致输出电压纹波过大或下降。
- 待机电源（Standby 5V）电路故障，主板无法上电启动。
- 电网浪涌或雷击导致电源板保险丝、压敏电阻、整流桥等元件损坏。
- 电源板上的电解电容因高温老化，容量下降导致带载能力不足。
自助排查
- 观察电视指示灯状态：完全无指示灯通常为待机电源故障；红灯闪烁可能为电源保护动作。
- 拔掉电源线 5 分钟后重新通电，排除偶发性保护锁定。
- 用万用表测量电源插座电压，确认市电在 220V±10% 范围内。
- 打开后盖，检查电源板上保险丝是否熔断——若熔断且发黑，说明后级有严重短路，不要直接更换保险丝。
- 电源板涉及高压电路（含 380V 直流母线），非专业人员操作有触电危险。若以上排查无果，请联系 TCL 售后，由专业维修人员检测或更换电源板。
English
Meaning
The TV power supply unit (PSU) has abnormal output voltages; the TV cannot be powered normally or shuts down automatically. E7 indicates the TV main board has detected that one or more power rails from the power supply board are out of their normal range.
Common Causes
- PFC (Power Factor Correction) circuit failure; the 380V DC bus voltage cannot be established or is too low.
- Inter-turn short circuit in the primary winding of the main switch-mode power transformer, causing the power supply to enter overcurrent protection.
- Failed rectifier diodes or filter capacitors on the power board output, causing excessive output voltage ripple or droop.
- Standby power (Standby 5V) circuit failure; the main board cannot be powered on.
- Grid surge or lightning strike damaging the power board fuse, varistor, rectifier bridge, and other components.
- Electrolytic capacitors on the power board aging due to high temperature, with reduced capacitance causing insufficient load capacity.
Self-Check Steps
- Observe the TV indicator light status: no indicator at all typically means standby power failure; a blinking red light may indicate power protection activation.
- Unplug the power cord for 5 minutes, then reconnect — this clears incidental protection latch-ups.
- Use a multimeter to measure the wall outlet voltage and confirm mains power is within 220V±10%.
- Open the back cover and inspect the power board fuse — if blown and blackened, there is a severe short circuit downstream; do not simply replace the fuse.
- The power board involves high-voltage circuits (including a 380V DC bus) — non-professional handling carries electric shock risk. If the above checks don’t help, contact TCL after-sales for a professional technician to test or replace the power board.