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1.松下TC-2185CR/D彩电“三无” 打开后盖检查进线保险丝,未熔断。从市电网络拔下彩电电源插头,接通电源开关测量AC220V进线电阻为39Ω(正常)。检查发现整流桥路的限流电阻R481(4.7Ω/7W)已开路,分析是电路有过流现象将R481烧毁。检查厚膜电源电路IC801(STR50213)内部电压调整管Q的c-e极电阻(即IC801③、④脚),正、反向均为0Ω。再查IG801④脚(+113V输出端子)对地电阻,黑笔测为250Ω,红笔测为4.8KΩ,说明本机的负载电路基本正常。进一步检查可控硅保护电路Q834,未见异常。更新上述坏损元件后试机,彩电恢复正常。
1. Panasonic TC-2185CR / D TV “three no.” Open the back cover to check incoming fuse, not blown. Unplug the color power plug from the mains network, turn on the power switch and measure the incoming resistance of AC220V to 39Ω (normal). Check found that the rectifier bridge current limiting resistor R481 (4.7Ω / 7W) has been open circuit, the analysis is the circuit has the phenomenon of over-current R481 burned. Check the thick film power circuit IC801 (STR50213) c-e internal voltage regulator tube resistance (ie IC801 ③, ④ feet), positive and negative are 0Ω. Then check IG801 ④ feet (+113 V output terminal) to ground resistance, black pen measured 250Ω, red pen measured 4.8KΩ, indicating that the load circuit of the machine is normal. Further inspection SCR protection circuit Q834, no exception. After updating the above components damaged test machine, color TV back to normal.