| Electronics > Beginners |
| Soldering iron that won't melt? |
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| Jookia:
Here's a photo of inside. Yes, there was a large unconnected piece of metal to make it feel heavy. Edit: Uh, does this mean I had mains voltage isolated by just electrical tape? :-\ |
| Zero999:
Yes, it's just a lamp dimmer. If you looked at the other side of the PCB and reverse engineered it, you'll find it's a standard lamp dimmer circuit, consisting of a TRIAC, DIAC, potentiometer and a couple of resistors and capacitors. The weight is essential to stop it from tipping over, when the soldering iron is in the stand. The soldering iron itself runs off the mains voltage, so insulating the cable with electrical tape is a bad idea. The entire cable should be replaced, preferably with a heat resistant one. Indeed the first thing I did with mine was replace the crappy PVC cable, with silicone one, before I got the chance to burn it. |
| Ian.M:
--- Quote from: Zero999 on August 30, 2019, 02:27:40 pm ---The soldering iron itself runs off the mains voltage, so insulating the cable with electrical tape is a bad idea. The entire cable should be replaced, preferably with a heat resistant one. --- End quote --- Bit late for that now. The handle should *NEVER* have melted like that, exposing live connections, as that's a major electrical safety fail. It should either be made of a thermoset plastic that can't remelt, or there should be a thermal fuse on the back of the mounting flange that blows before it reaches the handle melting point, or the connections should be touch proof even with the handle missing. Therefore I believe you have a good case that the device was potentially unsafe and therefore 'not fit for purpose' at the date of purchase. N.B. IANAL nor qualified to do electrical inspections, especially not in Australia. |
| ArthurDent:
There are a lot of similar irons and lots of rebranding so the name and model doesn't mean that much. Here is a photo of my base that has the same blue plastic case but a different dimmer circuit board and a connector so the iron itself can be unplugged from the base. I have turned mine up to 100% to heat some solder joints that were probably too massive for this size iron and left the iron at full for some time with no problem. If your iron got hot enough to do the damage shown I would guess that there was some shorted sections in the heater and that allowed the iron to get far hotter than it could if set to 100% and working normally. This problem could also occur if you had a 120 volt iron like I do and ran it from 220 volts. In my photo you can see that the 3 wires coming from the iron are ground/earth, 120 volt low, and 120 volt high through the dimmer circuit, there is no sensor on either mine or yours. In my photo you can see a small heat sink on the TO-220 triac on the side of the dimmer board. Even if you had damaged the dimmer circuit when you melted through the wires and the board shorted the iron would only see the line voltage and should be o.k. at 100% power. If it makes you feel any better I'd bet it was a problem with the iron and you had nothing to do with the problem. |
| Audioguru again:
The soldering iron is cheap, Chinese and maybe was never certified to be safe. If it caused a fire then your insurance company would laugh that you bought a cheap Chinese soldering iron. Claim denied! |
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