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现从大量的维修实例中选有代表性的几例,看过压、过流保护器在彩电中的重要地位。例一:一台黄河HC5404型54cm(21英寸)彩电出现“三无”。拆机检查,发现开关管、行管、行输出变压器损坏。将开关电源与行扫描电路分开进行检修:将开关管换新,并用100 W灯泡作假负载通电,灯很亮,速测B+电压上升到160多代,速关机,检查开关电源各元件。当检查C610时,发现电容量由47μF下降到18μF左右,将C610换新后通电,115V电压正常;将行扫描电路损坏元件换新后.联机,显像管内有紫光.并有打火声,说明显像管损坏漏气,由于这类机设计先天不足开关电源无过压保护功能,开关电源异常,造成B+大幅度上升烧坏许多元件,但是该机使
Now a large number of examples from the maintenance of selected representative of a few cases, seen over-voltage, over-current protection in the TV important position. Example 1: A Yellow River HC5404 54cm (21 inch) color TV “three no.” Disassemble inspection, found that the switch, line control, line output transformer damage. The switching power supply and line scanning circuit separately for overhaul: the switch for a new, and with 100 W bulb for the false load power, the light is very bright, rapid test B + voltage rise to more than 160 generations, speed shutdown, check the switching power supply components. When examining the C610, it was found that the capacitance decreased from 47μF to about 18μF, the C610 after the renewal of power, 115V voltage is normal; the line scan circuit damage to the new components. On-line, the picture tube with purple. CRT damage, due to the inherent design of this type of switching power supply without over-voltage protection, switching power supply anomalies, resulting in a substantial increase in B + burn many components, but the machine to make