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[例1]康佳PDP4218彩电,VSB(5V)电压正常,其他电压均为0V。分析与维修:因只有VSB电压正常,说明以IC8003(TOP223PN)为主的STB待机电压正常,故障在PFC(功率因素校正)电路或开/关机控制电路。测量电路板上的DC—VCC测试端,有正常的15V电压,说明开/关机控制正常,但再测量PFC测试点,电压为0V(正常值应为380V左右),说明故障在PFC产生电路。检查PFC的相关电路,发现整流桥D8003损坏。更换后,通电试机,故障排除。
[Example 1] Konka PDP4218 color TV, VSB (5V) voltage is normal, the other voltage is 0V. Analysis and Maintenance: Since only the VSB voltage is normal, the STB standby voltage based on the IC8003 (TOP223PN) is normal, and the fault is on the PFC (Power Factor Correction) circuit or on / off control circuit. Measuring circuit board DC-VCC test terminal, a normal 15V voltage, indicating on / off control is normal, but then measure the PFC test point, the voltage is 0V (normal value should be 380V or so), indicating that the fault circuit in the PFC. Check the PFC circuit and found the rectifier bridge D8003 damaged. After replacement, power test machine, troubleshooting.