Nothing is worse than having a tool break on you, and a broken soldering torch is no different. When you're ready to scrap it and get a new one stop for a moment, try these methods of fixing it first.
Step 1: Figure Out What Is Wrong with Your Soldering Torch
First things first, find out what is wrong with your soldering torch. The first thing you should check is the soldering torch cord and plug. Inspect the plug to make sure nothing is keeping the prongs from adequately drawing electricity from the socket. If there seems to be nothing wrong with the plug you should look into a connection problem with the cord. Start by disconnecting the cord from the appliance, double (maybe even triple) check to make sure it is not connected to any electrical source or conduit, you can never be too careful when dealing with even small voltages. Attach both ends of the cords to a continuity or multimeter tester and check to see if the cord is properly conducting electricity. If you rule out connection issues it could likely be a broken soldering iron filament.
Step 2: Put in a New Cord
Note: If the problem wasn't with the cord skip to step 3. Make sure the new cord you have is of the same rating and gauge as the cord you are replacing, as not every cord can go with every appliance. Remove the old cord from the inside of the soldering torch and attach the new one. Test the soldering iron, if the problem is not fixed move on to step 3.
Step 3: Remove the Broken Filament
Before you start messing with anything make sure everything is turned off and cooled. Even though it is broken, electrical appliances can be tricky and potentially dangerous and you can never be too careful. Gently grab the trunk of the tip with one hand and the handle of the soldering torch in the other hand and twist until it dislodges and you can open the open the soldering iron. Once open use a pair of cutter pliers to at the base of the filament to separate the attached wires of the soldering iron from the terminals of filament that it has been connected by.
Step 4: Attaching the New Filament
Place your new filament where the old one had been and connect its terminals of filament to the wires of the soldering iron. Use electrical tape around the new connections as a safety measure. Do a visual inspection to see if you can spot any problems and if not, reassemble the rest of the soldering torch.
Step 5: Give It a Test
Using all safety precautions recommended when using a soldering torch, turn it and see if it works. If it does, congratulations! You fixed your soldering torch! If not you won't have to waste any guilt while you're out getting a new one; rather, you can rest assured in the knowledge that you did everything you could to fix your old one.