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上门检修一台康佳T2992N大屏幕彩电,图像完全正常,伴音无规律地频繁出现断声故障,有时还伴有类似电路打火而产生的“吱——吱”的干扰声。打开机壳开机,摇动电路板伴音随之有明显变化,断声时调大音量,可听到微弱的伴音声。见此症状,心中暗喜,根据经验判断,这不过是在伴音功放电路部分焊点存在接触不良。满怀信心准备迅速拿下,但出乎意料的是将功放电路焊点全部复焊一遍,故障仍旧。不得不把故障范围扩大到CPU音量控制部分,以及通道板上主芯片OM8361的伴音信号处理相关脚周边部分。大面积复焊焊点后,开机再摇动机板故障未在出现,满以为故障已排除,谁知合上机壳后开机,断声故障再现。
Home overhaul a Konka T2992N large screen color TV, the image is completely normal, frequent sound irregularities often appear broken sound failure, and sometimes accompanied by a similar circuit sparking “squeak - squeak ” interference sound. Open the chassis boot, shake the sound accompanying circuit board significant change, when off sound when the volume, can hear the sound of weak sound. See this symptom, the heart of dark, according to the experience to judge, this is only part of the audio amplifier circuit solder joints there is poor contact. Confident ready to win quickly, but unexpectedly all the welding spot welding circuit amplifier again, the fault is still. Have to extend the scope of the fault to the CPU volume control section, as well as channel board main chip OM8361 audio signal processing related to the peripheral part of the foot. Large area after the reflow solder joints, the boot and then shake the board failure is not present, full that the fault has been ruled out, who knows the boot after the closure of the shell, broken sound reproduction.