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例1机型:青岛牌37CD445型故障现象:光栅缩小并伴有嗡嗡声。分析检修:根据现象分析,这种故障可能发生在开关电源或行扫描电路。首先检查开关电源电路,测量开关电源输出端的+113V电压为83V,+16V、+50V电压也都低于正常值,怀疑负载电路有问题。断开+113V端的负载,并接上一只60W的灯泡作为假负载,通电后灯泡点亮,测+113V电压已恢复正常,由此断定故障在行输出电路。再检查行输出电路,测量行输出管正常,断开行偏转线圈,测量+113V电源电压正常。试更换S校正电容C_(552),故障依旧,故判断是行偏转线圈有短路故障。拆下检查,发现在靠近高压帽处有几圈
Example 1 model: Qingdao brand 37CD445 type Symptom: grating narrow and accompanied by a buzz. Analysis and maintenance: According to the phenomenon analysis, this failure may occur in the switching power supply or line scan circuit. First check the switching power supply circuit, measuring the output of the switching power supply + 113V voltage is 83V, +16 V, +50 V voltage is also lower than normal, suspected load circuit problems. Disconnect the + 113V end of the load, and connected to a 60W bulb as a false load, the lamp is lit after power, measuring + 113V voltage has returned to normal, thus concluded that the fault line output circuit. Re-check the line output circuit, measuring the output line is normal, disconnect the deflection coil, measuring + 113V power supply voltage is normal. Try to replace the S correction capacitor C_ (552), the fault still, it is judged that the line deflection coil has a short circuit fault. Remove the check and find that there are a few turns near the high pressure cap