This iron has been giving trouble for some time. Depending on the angle it is held, it will lose power. A sure sign of a broken (open) cable. Time to fix this.
Step 1: Opening It Up.
Using a Phillips head screwdriver I opened the iron. This model uses a retractable reel for the cable. This design will always gives trouble. It's far better to have fixed chords.
You can see the cable reel. It depends on tracks and brushes. This is a point of failure and not a good idea for high wattage applications.
I condemned the reel since it was impossible to get the spring back in place. I cut off the cable in preparation for the next step.
Step 2: Finding and Removing the Open in the Cable.
Using my handy multimeter, I checked continuity and found the open in the cable. Most people incorrectly say a short in the cable. This is completely wrong. This is an open circuit defect which is also dangerous since is creates a high resistance point. When current flows through this high resistance point it will create lots of heat and hence fire potential.
Where my index finger is, that is where the open wire is. I cut that out.
Step 3: Reconnecting the Cable.
I always prefer soldered connections for durability. After soldering the wires, I zip tied the chord for strain relief.
Step 4: Reassembly and Testing.
Using the unsung hero, evostik, I put the back cover on since the screw holes were brittle and broke off.
Now the iron works again and has some more service life!