Help, help

zhangjr

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Hello, experts. Now I have encountered a phenomenon. I am currently using TI's TPS54331 DC-DC to output 5V and connect it to a 0.4mm pitch connector. When the board is powered on, the DC-DC outputs 5V normally, but the network next to the 5V network in the connector actually also has voltage, and the voltage is also around 5V. (As shown in the picture) What is the problem? Could it be that the 5V is coupled over, causing the network next to it to also have voltage? Help, help.

maychang

Is the circuit board leaking electricity? Is there insufficient corrosion resulting in invisible burrs or connections? All are possible.

okhxyyo

First check if there is any problem with the circuit board. Turn off the power and use a multimeter to test the circuit to see if there is a short circuit. Some circuit boards are not well made or there are other reasons. It is possible that the board is connected at a place that is not connected or the circuit is broken.

zhangjr

okhxyyo posted on 2018-7-16 16:30 First check if there is any problem with the circuit board. Turn off the power and use a multimeter to test the circuit to see if there is any short circuit. Some circuit boards are not well made or...

There is no short circuit on the board, and all the circuits on the bare board are good. There will be no problem with powering on the empty board.

qwqwqw2088

The coupling may be a small short circuit, and there will be no "network next to the 5V network in the connector". What is the situation of the network next to it? Maybe it has nothing to do with your 5V. Check the connection. The 5V must be connected, not necessarily the output of your connector.

ienglgge

, but the network next to the 5V network in the connector actually has voltage. Check if the network next to it is connected to an external device. It may be a signal generated by an external device.

zhangjr

maychang posted on 2018-7-16 16:26 Is the circuit board leaking? Is it not corroded enough to cause invisible burrs or connections? All are possible.

However, when testing the bare board, there is no problem when using a multimeter to test.

zhangjr

maychang posted on 2018-7-16 16:26 Is the circuit board leaking electricity? Insufficient corrosion leading to invisible burrs or connections? All are possible.

This is a picture of the board. When only the DC-DC module is soldered (without the connector), there is no voltage on the pins next to it, but after soldering the connector, the situation I mentioned will appear.

maychang

[quote]zhangjr posted on 2018-7-17 09:13 This is a picture of the board. When only the DC-DC module is soldered (without the connector), there is no voltage on the pins next to it, but after soldering the connector, the situation I mentioned will occur. Is there leakage on the pins of the connector itself? Take a few unsoldered connectors to test, and then test on the soldered connectors without turning on the DC-DC module.

qwqwqw2088

If you have the schematic diagram and PCB diagram, it will be easy to check each part after powering on and measure the DC-DC module part. It will be easy to find the problem

zhangjr

qwqwqw2088 posted on 2018-7-19 14:29 It would be easy if you have the schematic diagram and PCB diagram. It would be easy to find the problem by comparing the various parts and measuring the DC-DC module part after powering on.

The cause has been found. It was previously soldered manually. When using a hot air gun, the structure of the circuit board may have been damaged, resulting in coupling.

zhangjr

maychang posted on 2018-7-17 09:55 When soldering the DC-DC module (without soldering the connector), there is no voltage on the adjacent pins, but after soldering the connector, there will be...

The reason has been found, because it was manually soldered before, and the internal structure of the PCB may have been damaged when using the hot air gun and soldering iron, resulting in such a phenomenon. After going to the factory to mount the chips these days, the test board did not show the previous phenomenon. After consulting the staff of the patch factory, I came to the conclusion that I still have to thank the great gods for their help.