Technical
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Disassembly Skills of Chip Components on PCB
What Factors Should Be Considered in the Selection of High-frequency PCB CCL
How to Place Special Components during PCB Layout
What Are the Functions of Capacitors in Circuits?
Testing Techniques for Common Electronics Components
What to do if There is a Short Circuit on the PCB
Desoldering Principles and knowhow during PCBA Processing
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How long can PCBA finished products be stored?
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PCB Baking Specifications
PCB "Solder Mask Tenting" and "Solder Mask Opening"
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Explanation of BOM, DIP, SMT, SMD
Introduction of the process of PCBA prototype
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SMT processing solder joint quality inspection
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Compare of multi-layer PCB with single/double layer PCB
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Difference between immersion gold boards and gold plating boards
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How to choose capacitors for filter decoupling
How to choose filter capacitor for switching power supply
5 database need for SMT process
Function of three-terminal capacitor
Introduction of PCB OSP surface treatment
Method of inspecting the quality of SMT by step
How to find the short point between VCC and GND
Difference between 850nm and 940nm infrared LED
Component layout of PCB SMT DFM
Pad shape influence on the strength and reliability of the soldering joints
The difference between high temperature solder paste and low temperature solder paste
Introduction to manual welding processing
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Difference between hardware engineers and software engineers
PCBA processing operation rules
China PCB upstream materials has continued to soar
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The key points of quality control in PCBA processing
Common causes of solder beading during SMT process
Analysis of the advantages and disadvantages of HASL PCB surface
Requirements for layout of components during SMT assembly
Selection of electronic components and CCL for PCBA
Performance and appearance quality inspection of components.
Quality and Reliability of SMT Chip Processing and Production
Coupling and decoupling function of capacitor
Two methods to connect digital ground and analog ground
Common sense in SMT process

How to find the short point between VCC and GND

When debugging a circuit, you may often encounter a short circuit between VCC and GND. There are too many VCC and GND points on the board, and you may feel that don't know where to find the short point. Here are a few methods for your reference.

1. Visual inspection

The easiest way is to observe with the naked eye or a magnifying glass. Especially chips with fine pitch pins and small package capacitors are prone to short circuits when the soldering is not good. Sometimes conductive objects such as tin beads or copper wires may have fallen on the circuit board, just between the VCC and GND pins, causing a short circuit. This kind of problem is easier to solve, just use a soldering iron to deal with it.



2. Knife cut
For the board without obvious short circuit, it is very likely that the short circuit is caused by the damage of the components on the board. At this time, you can use a blade to cut off the suspected short-circuit part, and then conduct a test to find the problem step by step.
If you don't want to damage the circuit board, you can remove the suspected short-circuit components one by one, and then gradually eliminate them, but this method is more troublesome. If you are lucky, you may find it quickly, if not, you may have to remove the last one then find the problem.

3. Hand touch
Knife cutting and component removal methods are both troublesome and are rarely used. Another method is to touch the suspected chip after power-on. If the heat is abnormally severe, it must be damaged. Of course, be careful not to get hand scalded when touching it. In addition, because it has been short-circuited, the power-on time should not be too long, otherwise PCB may burn directly.

4. Thermal imaging camera observation

You can use instruments instead of hand touches, such as infrared thermal imaging cameras, which can easily find unusually hot places.


5. Colophony smoking

Finally, I recommend a simple and practical method, it also uses the phenomenon that a short circuit will generate heat. Smoke a layer of colophony on the circuit board, and then power on, the short circuit will generate more heat. Observe where the colophony melts, it shows where the short circuit is.