Have you been obsessed with the failure analysis of circuit boards for a long time? Do you spend a lot of energy in the process of sample debugging? Have you ever doubted your original correct design? Many hardware engineers may have had similar psychological conversations. According to statistics, 78% of hardware failures are caused by poor welding and wrong materials.

As a result, engineers spend a lot of time and energy on sample debugging and analysis, which delays the project progress. If the bad reason can't be found for a while, the engineer will doubt his original correct design and go astray in the wrong thinking direction.

When actually debugging hardware, engineers often consider many profound potential incentives, but they are unwilling to doubt whether the welding is reliable enough, and often "the safest place is the most dangerous place".

Engineers will habitually think that a simple thing like welding will not cause many seemingly complicated problems. Once such problems occur, they will also habitually consider the robustness of software and the rationality of hardware circuit design. For example:

1 case 1

Because a signal is virtually welded in the DDR high-speed signal part, the system seems to work normally when transmitting ordinary small data. However, in the sudden operation of big data, such as playing high-definition movies and loading the operating system, errors are often reported. But it is often mistaken for software, and software engineering teachers don't have time to check the code.

2 Case 2

Due to improper control of time and temperature during welding, plastic structural parts inside connectors such as LCD and USB are melted and deformed at high temperature, which leads to unexpected disconnection of signals, resulting in no display of LCD and no communication of USB, which is mistaken for a software driving problem.

3 case 3

A large number of decoupling capacitors are densely distributed next to the CPU power supply. As a result, a capacitor was short-circuited due to too much solder during welding, which led hardware engineers to spend a lot of time investigating the causes of short circuit one by one.

4 Case 4

High-speed signal interface connector, because of signal virtual welding, the system can work at a lower bus frequency. Once the bus speed increases, the system will report the error immediately. The cause of this problem is basically difficult to locate.

5 Case 5

Due to the poor welding of inductance, the PWM dimming function of LED is invalid, and engineers spend a lot of time to confirm whether it is a software problem or a hardware problem.

Welding, seemingly simple, is also made up of many work details and steps, and these links are also interlocking, and any error in any link will lead to the final problem. Therefore, in the process of hardware debugging, engineers are advised to observe the welding quality of your prototype first.

Is the material correct?

Is the foot position correct?

Is there any soldering, virtual welding or virtual welding?

Is the solder paste full and reflective after passing through the furnace?

Is there any brown on the PCB?

Will the structural part of the connector melt at high temperature?

Does the chip position correspond to screen printing?

After checking the above "simple" items, focus on those "profound" problems!