Looking for a soldering iron

[cent88]

Is it normal for a new soldering iron to have internal wiring burnt?
The tip was shorted and mains going through. Test pen light up brightly.

Awww... I bought 3 soldering irons in 3 days.
1st, cheap ones. don't know where is the origin manufacturer.
2nd, cheap ones. China made.
3rd, Hakko Red series 60watts. Same thing happened.

 

[stratus46]

Sounds like a 120 V iron on 240. Is that the case?

G²

 

[Iain McNeill]

no, burnt wiring is not normal.
Are you saying 3 irons have failed in the same way? Can it be they are 110V irons on 240V supply?

It's suspicious that all three tips "light up brightly"

 

[cent88]

no. all the soldering irons are verified for 230Vac.

impossible the power socket over supply the soldering iron? and it's burnt wiring.
because all 3 of the new soldering iron tested on the same power socket which my old soldering iron dead. but my mini-drill works well with it.

 

[cent88]

@Iain
yes. all failed the same way.
not the tips, I point the test pen to the tips.

 

[Iain McNeill]

Sorry, I might be misunderstanding you.

Please talk more about the "shorted tip" and the "mains going through"

Did you find the "internal wiring burnt" before or after you tried plugging in the irons?

 

[cent88]

@Iain
I won't get electric shock with previous soldering iron when soldering/holding solder lead.

There is some burning plastic smell after I plugging in the new irons, I suspect is the internal wiring. Test pen light up when I point to the tip(so is it short circuit?)

Besides that, the tip become blue and iron/heater(become hot and red) which holding the tip. seems like overheating. the PCB copper trace I soldered also turn into dark blue permanently.

 

[cent88]

Ok. I got it. My previous soldering iron is 3-pronged plug. the tip is ground to the earth.

I'll try lower wattage soldering iron. by the way, is it safe to use 2-pronged soldering iron? I'm worrying the non-grounded tip will damage the semi-conductor.

 

[cent88]

Modified the iron. Co-incidently there is a hole inside for me to screw.
Grounded the tip to earth.
Works perfectly good now, hopefully the green earth wire can withstand the heat from melting.

 

[Iain McNeill]

I think you'll find that the 2 prong iron tip is not connected to either prong on the mains plug (open circuit) However, the heater will have capacitance to the tip and so leakage current will flow lighting up neon test pen. Grounding as you have done should work.

The tips should not glow red or blue although the plating on the tip can turn blue color but this color stays even when tip is cold. Sounds like it it way too hot if it is discoloring the copper traces on the PCB. Can you check the temperature of the tip with IR thermometer gun? 200°C/350°F is good range much higher will do damage to components.