*The fault is that the module * is not working
There are many reasons for this situation. Firstly, the pin voltage needs to be measured, which is the easiest and simplest method of judgment. If there is an abnormality in the voltage, it needs to be checked separately to see if it is a problem with the power supply circuit or if there is a short circuit during module soldering. If it is a module of unknown origin, internal short circuit damage should be considered. For example, if the u-blox sample purchased from Feiyang Technology has anti-static packaging, these effects do not need to be considered. However, if the module is purchased from an unknown online channel, it should be considered whether it is a defective product or not, which should also be a key consideration

Generally speaking, if there is suspicion of quality issues, the possibility of a legitimate agency for electronic components is relatively small. However, if the product is purchased from the electronic market, the source of goods should be considered first. In this case, conducting experiments is like adding insult to injury

If it is a short circuit situation, current measurement can be used. If it is not convenient to test the current, it is necessary to touch the PCB substrate to see if any component or module has signs of heating. For the heating part, the possibility should be carefully analyzed

During the welding process of u-blox products in experiments, there may be a short circuit at the bottom of the manually welded module that cannot be observed by the naked eye. At this time, a meter should be carefully used to test whether there is a short circuit between two adjacent pins. If there is such a situation, the part will also heat up. Of course, if there is no short circuit at the periphery, a soldering iron should be used to heat up the part again and re solder the flux. Sometimes the short circuit is at the bottom and there may be too much solder. At this time, a hot air gun needs to be used to disassemble the module from the bottom and solder the removed module before re soldering. During welding, various temperature controls must be strictly paid attention to, and the module should be re soldered The high temperature should not exceed 250 degrees Celsius for 10 seconds. It is important to remember that all operating procedures must be correct in order to minimize the damage rate of the module during the experiment

Generally speaking, if the circuit itself is mature, the key consideration should be the bottom short-circuit welding problem mentioned above. After replacement, if the voltage of each pin is correct, in principle, the possibility of passing will be high

The second phenomenon of NO.2 is that the module voltage is normal but there is no NMEA code output
The reason for this situation may be that there is no 3V voltage applied to the VCC supply terminal of TTL level. First, test whether the pin wiring is normal, which is generally related to the TTL level circuit

The third phenomenon is that the module voltage is normal and there is NMEA output but no positioning information
There are many types of this situation, but the following situations are when the machine is placed outdoors during testing, without considering signal strength issues
If it is a passive antenna, attention should be paid to whether the peripheral lines are correct when using it outdoors
If an external active antenna is used, it is necessary to consider whether the RF [_] IN pin has a 3V power supply voltage. If not, it means that the 3V power supply circuit of the RF part is not provided. Focus on checking the power supply part of the RF part

The third phenomenon of NO.4 is that the module voltage is normal and there is NMEA output, but the USB interface cannot be used for communication
This situation mainly considers whether the USB power supply terminal of the module is normal, whether the DP+/DP - data cable is reversed, and another situation is whether its protective tube clamp is damaged. In emergency situations, the protective diode can be removed first for communication operations, and then specific experiments can be conducted later