PCB factory will encounter many problems after making the circuit board, no matter it is just made or it will appear in later operation process.Therefore, how to dislocate the circuit board is also very important.
The circuit that used to run very normal now suddenly not normal, the voltage source that connect sees current A bit more A, guess is power supply short circuit, measure with voltmeter discovery is really such.So you need to figure out where the circuit is short.
Behind a chip fever began to electricity is very big, doubt is the problem that the chip, removed after circuit still short circuit, then blind check along while, but have no effect at all, actually such problems should be settled down to, think carefully about how the connection between power supply and ground, and then think how to check it.Take the example I met today, later I analyzed the circuit, and found that the +5V is divided into analog +5 and digital +5, which are connected by 0 ohm resistance, so we can see which part of the power supply and ground short circuit.After removing the 0 ohm resistor, it was found that there was no short circuit between the digital 5v and the ground.And then you look at the end, and you have the digital and the analog, and you want to do the same thing, but when you take the 0 ohm away, you find that the analog and the digital are still connected, because I have the chip welded on my board, and the analog and the digital are directly connected.
Therefore, I can only solve the problem one by one. In this case, I should find the line of my analog 5v power supply by cutting it in the middle to determine whether it is a short circuit in the first half or in the second half.And I cut it twice and I found the problem. I had a chip that burned.Change into a new one and put it away.Later judgment short circuit, must clear the thought!