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收录机在放音较小时音质正常,说明收音高频电路和前置放大器工作正常,声音开大便出现“打嗝”声的间歇振荡。此故障原因有四种:(1)电源系统滤波电容量减小或失效。(2)功能电路中某些管子发热,性能改变。(3)功放块外围阻容元件变质、失效,或功放块本身损坏。(4)电流路径上由于开关器件或开关元件接触电阻增大,经过功放的电流忽大忽小。以下举例加以说明。例1:一台熊猫SL-06型收录机出现上述故障,查电源电路正常,用一块军用13.5伏电池直接用于功放块TA7240P的正负电极上。声音变坏,功放块发热严重。故断定功放块的性能变差,换上新的就恢复正常。
Tape recorders in the playback sound quality is normal, indicating that the radio frequency circuit and preamplifier work properly, the sound of open stool “hiccups” sound intermittent oscillation. There are four reasons for this failure: (1) power system filter capacitance decreases or failure. (2) Some tubes in the functional circuit generate heat and the performance is changed. (3) Peripheral resistance element of the power amplifier block is deteriorated, invalidated, or the amplifier block itself is damaged. (4) current path due to the switching device or switching element contact resistance increases, the amplifier after the current suddenly big big suddenly small. The following example to illustrate. Example 1: A panda SL-06 tape recorders appear above failure, check the power supply circuit is normal, with a military 13.5 volt battery directly on the positive and negative power amplifier block TA7240P. Bad sound, amplifier block serious heat. It is concluded that the performance of the amplifier block worse, put on the new to resume normal.