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(九)录音无声 1.内录、外录、线路录全无声,但抹音良好观察机芯,录放磁头及抹音磁头都到位。磁带上原来的信号被抹去,但新的信号并没有录上。测量录放磁头发现没有偏磁电压,偏磁电路不工作。其原因是录放开关不到位。只要录音推杆位置安装正确,在录音状态时,录放开关就能到位,使偏磁电路正常工作,录音功能恢复。 2.话筒录音无声用万用表测量录放磁头,其左、右两路偏磁电压都属良好,音频电流通路也属正常。检查内录话筒,发现其引出端与印刷线路板假焊,造成话筒录音无声。 3.线路录音无声线路录音不良的原因主要有两点。一是线路输入插座不良或开路;二是对录线与本机线路输入阻抗不
(IX) Sound recording is silent 1. Internal recording, external recording and voice recording are silent. However, the wiping sound is good to observe movement, recording and reproducing heads and erasing heads are in place. The original signal on the tape was erased, but the new signal was not recorded. Measuring recording head found no bias voltage bias magnetic circuit does not work. The reason is the recording switch is not in place. As long as the recording pole position is correctly installed, the recording state, the recording and playback switch will be in place, the bias circuit to work properly, recording function recovery. 2. Microphone recording silence with multimeter recording head, the left and right two bias voltage is good, the audio current path is normal. Check the microphone inside and found that the lead-out end and the printed circuit board false welding, resulting in silent microphone recording. 3. There are two main reasons why the line recording is silent. First, the line input socket bad or open; second line and the local line input impedance is not