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1 故障现象 主监视器显示图象模糊,副监视器不亮。2 故障检修 根据故障现象,首先操作面板上各键钮,各控制键钮均能正常起控。将灵敏度调到最大,超声图象仍然模糊,调节主监视器的对比度及亮度旋钮,也无明显改观。试用副监视器的视频信号源（VIDEO IN端子进线）接到主监视器的视频输入端,故障依旧。断开副监视器的主电源,去掉副监视器与主机的连接,开机观察,主监视器上图象质量恢复正常。可见主监视器的图象模糊故障与副监视器的连接有关。接上副监视器电源,测量电源电压为8.7V,正常应为12V。由此可判断,由于副监视器负载加重,使得主机工作电压降低,从而降低了图象质量。 将副监视器移至机外,主电源12V用稳压电源代替,开机试验,负载电流达3.5A,机内存
1 Malfunction The main monitor shows that the image is blurred and the sub-monitor is off. 2 Troubleshooting According to the fault phenomenon, first operate the keys on the panel, and all the control buttons can start normally. With the sensitivity adjusted to the maximum, the ultrasound image is still blurred, and the contrast and brightness knobs of the main monitor are adjusted without any significant change. The video source of the trial secondary monitor (VIDEO IN terminal line) is connected to the video input of the main monitor, and the fault persists. Disconnect the main power supply of the sub-monitor, remove the connection between the sub-monitor and the host computer, turn on the watch, and the image quality on the main monitor will return to normal. It can be seen that the image blurring failure of the main monitor is related to the connection of the sub-monitor. Connect the sub-monitor power supply and measure the power supply voltage to 8.7V. Normally it should be 12V. From this, it can be judged that due to the increased load of the sub-monitor, the operating voltage of the host is reduced, thereby reducing the image quality. The sub-monitor is moved to the outside of the machine, and the main power supply is replaced with a regulated power supply. The power-on test is carried out and the load current reaches 3.5A.