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Many people do not know much about the maintenance of circuit boards. Next, FS Technology will explain the maintenance skills of PCBs.

1. Observation method

When we receive an FS Tech PCB for repair, we first take a closer look at what it looks like. If the PCB is burnt, please confirm that the power supply PCB is normal before turning on the PCB, and then turn it on again to ensure that no secondary damage will be caused. The observation method is a static verification method, when using the observation method, the following steps are usually followed.

Step 1: Check whether the PCB is artificially damaged;

Step 2: Check whether the PCB components are burned out;

Step 3: Test the integrated circuits in the PCB;

Step 4: Check the chain for loose, burnt or damaged caterpillars. It is a copper hole that sinks from the platform;

Step 5: Check the fuses (including fuses and thermistors) in the FS Technology PCB to make sure the fuses are not blown. Sometimes the fuse is too thin to see, and auxiliary equipment such as a multimeter can be used to determine whether the fuse is damaged.

2. Fixed measurement method

For most printed circuit boards, previous methods of observation do not detect problems. Although a small number of PCBs may be physically deformed for some reason, the cause of the failure is not difficult to determine. point on the graph. Methods of measuring, identifying and solving problems.

Before measuring, first determine whether the circuit is controlled by an analog or digital signal. The following are just standard methods for measuring digital circuits, and management basically follows the steps below.

Step 1: Use a multimeter to check whether there is a short circuit between the power supply and the ground;

Step 2: Measure the diode with a multimeter and check that it is working properly;

Step 3: Use a resistance multimeter to measure the capacitance to see if it is a short circuit or an open circuit. If there is, it means that there is a problem with this part of the FS technology circuit. The unit or circuit associated with it. ;

Step 4: Measure integrated circuits, transistors, resistors, etc. with a multimeter. In the PCB, see if they match their own logic characteristics

Tips and Warnings Most PCB management issues can be resolved by reviewing both observational and static measurement methods. Remember that the power supply must be normal, so as not to damage the secondary circuit after the next step.

3. Network measurement method

The Internet measurement method is commonly used by manufacturers who produce PCBs in series. . Internet measurement methods basically solve two problems. The first is to isolate the problems found in the first two steps, and finally the problematic components are eliminated. Second, in the above two-stage test, the problem is not resolved, so the cause of the failure must be determined through Internet measurements. The Internet measurement method is mainly used to compare two good and bad PCBs, through which problems can be found and solved.

In this article, FS Technology will explain in detail the types of PCB components and different types of packaging techniques, hoping to help you improve your PCB assembly technology. The following is the content of this article:

Classification of printed circuit board components

Diode is a very common PCB component. It has four colors: red, yellow, green and blue. According to the brightness, FS Tech divides it into three grades: normal, high and super bright. Light-emitting diodes test the purchasing ability of PCB assembly companies very much. Three kinds of diodes like 0805, 1206 and 1210 are difficult to buy, unless it is a one-stop PCB manufacturing company with PCB component purchasing ability like FS Technology.

We generally divide capacitors into two types: non-polar and polar. It is relatively easy to purchase capacitors, especially 0805 and 0603, which are very common non-polar capacitors on the market. Polar capacitors refer to electrolytic capacitors, which are very common in displays such as TVs and computers. It is what we usually call electrolytic capacitors. In our life, the most used aluminum electrolytic capacitors. Since the electrolyte is aluminum, its temperature stability and accuracy are not very high, and the chip components need high temperature stability because they are close to the circuit board. Therefore, the chip capacitors are mostly tantalum capacitors. SMD capacitors can be divided into four series A, B, C and D according to their different withstand voltages. The specific division is as follows:

A 3216 10V

B 3528 16V

C 6032 25V

D 7343 35V

Resistors: Similar to non-polar capacitors, the most common two are 0805 and 0603. The difference is that they can appear as exclusions, 4 and 8. The specific package style can refer to the MD16 simulation version, or you can check the internal PCB library of the design institute.

Note: The four package forms of A\B\C\D are L X S X H

The specific dimension of the 1210 is the same as the electrolytic capacitor B type 3528

0805 specific size: 2.0 X 1.25 X 0.5

1206 specific size: 3.0 X 1.5 0X 0.5

Common PCB component package size

If you are using high power transistors, FS Technology recommends you to use TO-3, the shape of this transistor is straight, we often use it when doing PCB assembly. Medium power transistors are generally flat, you can use TO-220. Low-power transistors include TO-5, TO-46, TO-92A. If you have special needs and need to use metal casing PCB components, when choosing transistors, you can try TO-66.

Component packaging

Resistors: RES1, RES2, RES3, RES4; package properties are axial series

Nonpolar Capacitors: Capacitance; package properties are RAD-0.1 to rad-0.4

Common component package size

Electrolytic capacitors: electroi; package properties are rb.2/.4 to rb.5/1.0

Potentiometer: pot1pot2; package properties are vr-1 to vr-5

Diode: Package property is diode-0.4 (low power) diode-0.7 (high power)

LED: RB.1/.2 [H]

Triode: Commonly used package attributes are to-18 (ordinary triode) to-22 (high-power triode) to-3 (high-power Darlington tube)

There are 78 and 79 series regulator blocks; [h]
78 series such as 7805, 7812, 7820, etc.

79 series has 7905, 7912, 7920, etc.

Common package attributes are to126h and to126v[h]
Rectifier bridge: BRIDGE1BRIDGE2: Package attribute is D series (D-44, D-37, D-46)

Field effect transistor and triode are the same

Crystal XTAL1[h]
Resistance: AXIAL0.3-AXIAL0.7 where 0.4-0.7 refers to the length of the resistance. Generally use AXIAL0.4

Ceramic capacitors: RAD0.1-RAD0.3. Among them, 0.1-0.3 refers to the size of the capacitor, generally RAD0.1

Electrolytic capacitor: RB.1/.2-RB.4/.8 where .1/.2-.4/.8 refers to the size of the capacitor. Generally 470uF use RB.3/.6

Diode: DIODE0.4-DIODE0.7 where 0.4-0.7 refers to the length of the diode, generally DIODE0.4 is used

LED: RB .1/ .2

Button SW-PB Package Properties KEYSB3

Integrated block: DIP8-DIP40 Among them, 8-40 refers to how many pins there are, and pin 8 is DIP8
[h] Chip resistor 0603 indicates that package size is related to resistivity, but package size is related to power