SM128V IBA  电路板检测

【产品详情】

SM128V IBA 便携显微镜进行电路板检测

1.<测试仪>对器件的检测,仅能反应出截止区,放大区和饱和区.但不 能测出工作频率的高低和速度的快慢等具体数值等.

2.同理对TTL数字芯片而言,也只能知道有高低电平的输出变化.而无 法查出它的上升与下降沿的速度.

四.晶体振荡器

1.通常只能用示波器(晶振需加电)或频率计测试,万用表等无法测量, 否则只能采用代换法了.

2.晶振常见故障有:a.内部漏电,b.内部开路c.变质频偏d.外围相连电 容漏电.这里漏电现象,用<测试仪>的VI曲线应能测出.

3.整板测试时可采用两种判断方法:a.测试时晶振附近既周围的有关 芯片不通过.b.除晶振外没找到其它故障点.

便携式显微镜检测电路板

4.晶振常见有2种:a.两脚.b.四脚,其中第2脚是加电源的,注意不可随 意短路.五.故障现象的分布 　1.电路板故障部位的不完全统计:1)芯片损坏30%, 2)分立元件损坏30%,

3)连线(PCB板敷铜线)断裂30%, 4)程序破坏或丢失10%(有上升趋势).

2.由上可知,当待修电路板出现联线和程序有问题时,又没有好板子,既 不熟悉它的连线,找不到原程序.此板修好的可能性就不大了.

SM128V IBA  电路板检测

【英文介绍】

Portable microscope for circuit board inspection

1.< tester > The detection of the device can only reflect the cutoff region, the amplification region and the saturation region. However, it is not possible to measure specific values such as the working frequency and speed.

2. Similarly, for TTL digital chips, it can only know that there are high and low level output changes. There is no way to find out the speed of its rising and falling edges.

Four. Crystal oscillator

1. Usually only oscilloscope (crystal oscillator needs to be powered up) or frequency meter test, multimeter can not be measured, otherwise only substitution method can be used.

2. Common faults of crystal vibration are :a. internal leakage,b. internal open circuit c. metamorphic frequency deviation d. Peripheral capacitance leakage. The leakage phenomenon here should be measured by the VI curve of the < tester >.

3. Two judgment methods can be used when the whole board is tested :a. The relevant chip near the crystal oscillator does not pass the test. No other fault points were found except for the crystal oscillator.

Portable microscope inspection circuit board

4. There are two kinds of crystal vibration :a. two feet.b. four feet, of which the second foot is added to the power supply, pay attention not to short circuit at will. 1. Incomplete statistics of the fault parts of the circuit board :1) chip damage 30%, 2) discrete component damage 30%,

3) 30% of the wiring (PCB coated copper wire) is broken, and 4) 10% of the program is damaged or lost (with an upward trend).

2. From the above, when the circuit board to be repaired has a connection and a program problem, there is no good board, neither familiar with its connection, can not find the original program. The board is unlikely to be repaired.

SM128V IBA  电路板检测

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