中文
含义
康佳空调检测到 5V 电源保护动作。E7 错误代码表示室内机或室外机主板上的 5V 直流供电电压异常或已触发过流/过压保护。5V 电压是主板 MCU（微控制器）和传感器电路的核心供电，该电压异常将导致空调完全无法运行或运行中突然停机。
常见原因
- 主板上的 5V 稳压电路（7805 或 DC-DC 模块）损坏，输出电压偏高或偏低。
- 5V 负载短路——传感器、继电器或通信芯片内部短路拉低 5V 电压。
- 开关电源初级侧故障导致变压器次级输出电压整体异常。
- 主板上的滤波电容（电解电容）老化漏液或鼓包，5V 纹波过大。
- 5V 保护电路自身误触发——光耦或电压检测分压电阻老化漂移。
- 雷击或电网浪涌导致主板电源部分损坏。
自助排查
- 断电后断开空调与电源的连接，等待 10 分钟后重新插电开机。
- 断开所有传感器和显示面板的线束，仅保留主板供电——如果 E7 消失，说明某传感器或外设短路拉低 5V 电压。
- 检查主板上的电解电容是否有鼓包、漏液或防爆阀打开的现象。
- 使用万用表测量主板上 5V 测试点的电压（正常应在 4.75-5.25V 范围内）。
- 5V 电路故障涉及开关电源检修，有触电风险。请立即联系康佳售后上门维修。
English
Meaning
The Konka air conditioner has detected a 5V power supply protection event. Error code E7 indicates that the 5V DC supply voltage on the indoor or outdoor main board is abnormal or has triggered overcurrent/overvoltage protection. The 5V rail powers the main board MCU and sensor circuits; an abnormal 5V supply will cause the AC to be completely inoperable or to shut down suddenly during operation.
Common Causes
- The 5V regulator circuit (7805 or DC-DC module) on the main board is damaged, outputting voltage out of spec.
- A short circuit on the 5V rail — a sensor, relay, or communication chip is internally shorted, pulling 5V low.
- A primary-side fault in the switching power supply has caused all secondary voltages to be abnormal.
- Filter capacitors (electrolytic) on the main board have aged, leaked, or bulged, causing excessive 5V ripple.
- The 5V protection circuit itself is falsely triggered — an aged optocoupler or voltage-sensing resistor divider has drifted.
- Lightning strike or mains surge has damaged the power section of the main board.
Self-Check Steps
- Power off, disconnect the AC from the mains, wait 10 minutes, then reconnect and power on.
- Disconnect all sensor and display panel wiring harnesses, keeping only the main board powered — if E7 clears, a shorted sensor or peripheral is pulling down the 5V rail.
- Inspect electrolytic capacitors on the main board for bulging, leakage, or open safety vents.
- Use a multimeter to measure the 5V test point on the main board (normal range: 4.75-5.25V).
- 5V circuit faults involve switching power supply repair and carry electric shock risk. Contact Konka after-sales service immediately.