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Like any other machine, soldering irons will also encounter troubles and breakdowns throughout the long run. If your soldering station doesn’t heat up anymore, usually the basic reason behind this is that the heating filament of your device has worn out. Most soldering stations consists a ceramic heating element that behaves as a heat source for soldering. As with all resistive heating tools, the element will eventually burn out with use over the time. The heating element of the majority of high-end soldering stations can be replaced.
For replacing the heating element, many users send the device to the service center, which can be quite expensive in the long run. There are many who do the replacement on their own. This not only cuts out the expenses but also save the unnecessary waste of time.
For inexperienced users, it can be very difficult to sort out the trouble and repair the device. To help you out I have created this step by step guide for testing and replacing the heating filament of your soldering iron.
Step 1: Get Tools Ready
First, you must assemble all the necessary items.
- The broken Soldering iron that needs replacement of the heating element.
- Brand new soldering iron filament for replacement. The wattage of the heating element may vary depending on the soldering iron that you are going to fix. The power of the heating element must be equal to the wattage rating of your soldering device. For example, if your soldering iron has power wattage of 20 watts, then you must use a 20 watts element.
- Electrical tape can be handy at times.
- A working soldering iron with the wattage of around 20 to 35 watts is necessary to desolder and solder the terminal connections for detaching and attaching of the old filament and the new filament respectively. If you don’t have an extra soldering device other than the one being repaired, you can borrow one from your family or friends. Else, you can also rent one from a rental shop.
- Solder for soldering the connections after replacing the heating filament. A lead-based solder would work great.
- Solder removing tool for removing the solder while desoldering.
- Wet sponge for cleaning the soldering iron tip.
Step 2: Test the Filament and Remove the Terminal Board
The first step should be to verify if the heating filament is indeed burned out and not working. Measure the values of resistance at both heating element and the temperature sensor using a multi-meter. The resistivity of the heating filament should range between some ohms, depending on the type of unit. A reading that shows several thousand ohms or more than that would mean that the heating element in the soldering iron has actually burned out.
In most soldering stations the heating element is connected between two pins on the soldering iron receptacle. In case the measurement of resistance was between the correct ranges, the temperature sensor must then be measured. This measurement is done with the remaining two pins on the receptacle of the soldering iron and should be between the specific ranges as indicated in the manual of your soldering iron. If any of these values are incorrect, the heating filament needs a replacement.
Now remove the nut, enclosure, tip and the nipple. Remember to remove the nut first then the nipple. Removing the nipple before could result in twisted heater leads, causing a short circuit. Now push the assay of the cord in the direction towards the tip and take the terminal board out of the handle. In case the terminal board is covered with a tube, remove the tube. Then remove the grounding spring located at the sleeve.
Step 3: Desolder and Detach
Power your working soldering iron and set the temperature. When the tip is hot, clean it using the wet sponge. Now that you have already removed the terminal board, it’s time to desolder the sensor leads and the heating element leads and remove the old filament. To do this, desolder the four wire connections of the old filament and remove it from the terminal board. Before removing, make sure that you have noted down the location of all the four connections on the terminal board. Now detach the metal protector attached to the bottom of the old filament.
Step 4: Solder and Attach
Hold the metal protector and attach it to the new heating element. Now bend the leads of the element and sensor at a right angle and pass the leads through the holes of the terminal board and push down the lead inside the board, then solder it. Make sure that the insulation that coverers the lead is wide enough not to leave any wire exposed. In case the wire is long, cut it and leave no longer than 1 mm to 2mm from the solder connection.
- Make sure that a specific color wire of the heating element is connected to the wire terminal having the same color.
- No polarity is there between the leads of the same colors, so if there are two sets of similar colored wires on the terminal and heating element then you can connect any wire from the terminal to the filament.
- Make sure that the solder in the joints is visible on the terminal board from both sides.
Step 5: Move Back Tube to Original Position
Re-installed the plastic retaining nut on the handle’s base and tightened it. To accomplish the re-assembly, ensuring that the smaller part is introduced first, slide up the tip holder on, then insert the soldering iron tip, and finally secure it using the tip enclosure and copper nut.
Now follow the same procedure used in testing the filament earlier, to determine if the new heating element is correctly installed and working fine if the measurements are correct.
To make sure that soldering temperatures are accurate, always calibrate the temperature of the soldering iron after replacing the heating element by connecting the iron to the power station. Use a special thermometer to check if the temperature of the iron tip is similar to the temperature that has been set on the power station. If it’s not same, use a screwdriver to recalibrate the device.
This procedure can be applied to almost all soldering stations that include a resistive heating element. I also want to let you know that in case you don’t want to go through the process of changing the filament and can afford to replace the entire handle every time the filament wears out then replacement handles are available for most high-end soldering stations.