The circuit board manufacturer tells you how to detect the failure of the FPC?

The circuit board manufacturer tells you how to detect the failure of the FPC?

The Circuit board manufacturer, circuit board designer and PCBA processor explain to you how the circuit board manufacturer tells you to detect the failure of the FPC?

Flexible circuit board, also known as "flexible board", is a printed circuit made of flexible insulating substrate. Flexible circuits provide excellent electrical performance, can meet the design requirements of smaller and higher density installations, and can also help reduce assembly processes and enhance reliability. Flexible circuit board is the only solution to meet the requirements of miniaturization and mobility of electronic products. It can bend, wind and fold freely, can withstand millions of times of dynamic bending without damaging the wire, can be arranged arbitrarily according to the spatial layout requirements, and can move and expand freely in three-dimensional space, so as to achieve the integration of component assembly and wire connection; Flexible circuit board can greatly reduce the volume and weight of electronic products, which is suitable for the development of electronic products in the direction of high-density, miniaturization and high reliability.

Flexible Printed Circuit Board (FPC) is referred to as "flexible board", commonly known as FPC in the industry. It is a flexible insulating substrate (mainly polyimide or polyester film) The printed circuit board has many advantages that the hard printed circuit board does not have. For example, it can bend, wind and fold freely. The volume of electronic products can be greatly reduced by using FPC, which is suitable for the development of electronic products in the direction of high density, miniaturization and high reliability. Therefore, FPC has been widely used in aerospace, military, mobile communications, laptops, computer peripherals, PDAs, digital cameras and other fields or products.

The cause of soft board damage is that some of the components on the board are damaged. How to detect a soft board failure? The small editor of the circuit board factory will tell you!

How to detect and repair soft boards

1. Usually, only oscilloscope (the crystal oscillator needs to be powered on) or frequency meter can be used for testing, and multimeter can not be used for measurement, otherwise, only substitution method can be used.

2. Common faults of crystal oscillator include: internal leakage; Internal open circuit; Deterioration frequency offset; The capacitor connected to the periphery leaks electricity. The leakage phenomenon here can be measured with VI curve<tester>.

3. Two judgment methods can be used during the whole board test: relevant chips near the crystal oscillator (i.e., around the crystal oscillator) fail during the test; No other fault points were found except crystal oscillator.

4. There are two kinds of crystal oscillator: two feet; Four pins, of which the second pin is powered on, please note that no random short circuit is allowed.

Function and parameter test

1. <Tester>For the detection of devices, only the cut-off area, amplification area and saturation area can be reflected, but the specific values such as the working frequency and speed can not be measured.

2. Similarly, for TTL digital chips, only high and low level output changes can be known, but the speed of its rising and falling edges cannot be detected.

Reset circuit

1. When there is a large-scale integrated circuit on the soft board to be repaired, pay attention to the reset problem.

2. Before the test, it is better to replace the device, turn on and off the machine repeatedly for a try, and press the reset key several times.

Chip with program

1. EPROM chip should not be damaged generally, because this chip needs ultraviolet light to erase the program, so the program will not be damaged during the test. However, it is reported that due to the material used to make the chip, it may be damaged (mainly the program) even if it is not used over time (years), so it should be backed up as much as possible.

   
   

2. EEPROM, SPROM, etc. as well as RAM chips with batteries are very easy to damage the program. Whether such chips damage the program after VI curve scanning with<tester>has not been determined. Nevertheless, it is better for friends to be careful when encountering such a situation.

3. For the chip with battery on the soft board, do not remove it from the board easily. The circuit board manufacturer, circuit board designer and PCBA processor explain to you how the circuit board manufacturer tells you to detect the failure of the FPC?