I bought another soldering iron, very expensive to me. I am very exciting about it. Upon receiving it, My heart is broken. First, I saw the label, 220V; Our AC voltage is 110V. Tried it, doesn't work. Not even heating up.
With a heavy heart, I disassembled it, trying to fix it. Great news, the heating element is measured 62 ohm, so It should work with 110v. I have tried to change 40K to 20K, and 1K to 500, but it doesn't work.
Here is the schematic that I got from tracing the PCB. There is a MCU supposedly used to controlling the duration of the triacs, thus giving it a variable temperature. Also, it's a 120W soldering iron. For me, I can live with fixed power @ 60W. what should I do here? I am not very familiar with AC circuit.
Best Answer
Rather than do all that engineering and risk damaging the soldering iron, for such a small load (120W) I'd suggest just getting a commercially available 120V to 240V transformer or adapter in the 200W capacity range. They're not expensive.
Also, there's a provision for installing 220/240V outlets in North America. It uses these outlets made for 240V which install exactly the same as common 120V outlets, except keyed different. It's called NEMA 6-15. 240V breaker and you're done.