1. Preparations before Soldering
• Check the status of the soldering iron tip: Scrape the chisel-tip soldering iron on a water-soaked sponge several times lightly to ensure that the surface of the soldering iron tip is smooth, shiny, and none of black spots. So it is easy to hold solder, and there is no aged solder on it.
• The soldering pads: After applying solder to the soldering pads, slide the soldering iron tip left and right to remove the aged solder, making the soldering pads as large as possible and the solder brighter.
2. Soldering Resistors/Wires
• Remember to prepare the soldering pads before soldering, and then start soldering: apply a little bit of solder to one of the soldering pads, and make sure to leave a little solder on the soldering iron tip for easier soldering.
• Hold the resistor with tweezers in your left hand (keep your hand steady) and place it right in the middle of the right place. Pay attention to aligning the component properly. Hold the soldering iron tip against the top of the resistor with your right hand, and keep it for two or three seconds. Melt the solder on the soldering pad and connect it to one end of the resistor. Finally, slide the soldering iron tip downward to remove the excess solder.
• Now the position of the resistor is basically fixed. Then, solder the other end. Hold the solder wire in your left hand, and bring the other side of the chisel-tip close to the other end of the resistor. Keep the solder wire about 2mm away from the soldering point, and let the solder flow naturally onto the soldering pad to ensure that the solder joint is round and none of burrs.
• Use the same method to add a little more solder to the other end.
• After soldering, be sure to conduct an inspection to ensure there are no cold solders, and use a multimeter in continuity mode to verify the electrical connectivity of the circuit.
• Pay attention to the skin effect of copper wires. Remember to apply solder to the stripped copper wires before soldering. The useful method is as follows: Use wire strippers to strip an appropriate length of copper wires, and twist the scattered copper wires clockwise into a single strand by your hands. Expose a part of the solder wire on the edge of the table. Hold the wire in your left hand, bring the soldering iron tip close to the solder wire with your right hand, and then bring the wire close to the soldering iron tip. Then the solder will automatically penetrate into the copper wires.
More Information:
- The 0603 and 0805 packages have a large impact on high-frequency small signals. Pay attention to the differences.
- When the distance between the two soldering points is large, but the component is small, it is preferred to use solder for connection first, and then consider jumper wires.
- solder wires or copper wires can be used as jump wires.
- Do practice more, and you will become proficient through repetition!
3. Soldering Multi-pin Chips
• Fix two diagonal pins with a little solder.
• Clean the soldering iron tip with a wet sponge, and dip it in rosin (or flux). Cover all the pins in a row with rosin.
• Apply a little solder (not too much) to the middle of the Knife-tip. Bring the tip close to the first pin and slowly pull it downward, while shaking the soldering iron tip left and right to prevent soldering bridges.
• Note: If there is a soldering pad in the middle of the chip, use a soldering iron to scrape off the solder in the middle, or use a desoldering pump to remove it. First fix one pin (preferably choose a pin next to the components), then adjust the position of the chip, and then solder the other pins.
4. Desoldering Resistors
• Place the soldering iron tip on top of the resistor. After a few seconds, when the solder under the resistor melts,gently pry it out with the soldering iron tip. You can add some solder if necessary.
5. Desoldering High-voltage Triaxial Cables
• When desoldering a high-voltage triaxial cable, there are a total of five soldering points. Use a chisel-tip soldering iron to scrape off the excess solder to create a gap. You can use a desoldering wick to absorb the excess solder (after melting the solder with the soldering iron tip, place the desoldering wick, dip the soldering iron tip in rosin, and press it closely against the desoldering wick). This can separate the component from the soldering pads. When there are still two soldering points connected,please move the soldering iron tip back and forth quickly between the two sides while gently shaking the component to remove it.
• Checking the leakage of the triaxial cable: Set the 2657 SRC to range 3K, DIS to range 1nA, and set the SPEED to high speed. Connect the HI terminal to the triaxial cable. A leakage current of a few picoamperes to a dozen picoamperes is considered normal. If the leakage current is abnormally high, you can wipe the tip of the triaxial cable and test it again (it may be caused by sweat or rosin).
6. Desoldering BNC Connectors
• There are 6 soldering points in total. Set the hot air gun to 450 degrees Celsius, 6-level wind force, and keep a distance of 0.5 cm. Blow in a circular motion around the soldering points. After 30 seconds, use a wire to poke one of the pins to help detaching it. BNC connectors are not damaged easily , so we do not need to test them.
• Note: The hot air gun can usually blow it off within one minute. If there is no reaction after a long time, you can increase the temperature or the wind force. The key is to blow it in a circular motion to make the board heat evenly and avoid damage or blackening.
7. Desoldering SOIC-8 Chips
• Use a hot air gun at a wind force of 5 and a temperature of 400 degrees .
• After cleaning the soldering iron tip, apply solder to both sides . Place the soldering iron tip on both sides of the chip alternately every 1 second.
• Note:
• If the melting is slow, add a little more solder to both sides , and place the soldering iron tip on both sides alternately.
• The movement of the soldering iron tip must be gentle. When it is time for the chip to fall off, gently pry it, otherwise it will damage the chip and the copper traces!
Note: Remember to turn off the soldering iron after use. Otherwise, the soldering iron tip will oxidize and turn black, making it unable to hold solder .
Temporary solution: While the soldering iron is still hot, use a blade to scrape off the black oxide on the soldering iron tip (or rub it several times on a watered-sponge), and then apply some solder to protect the tips.
