Ersa Icon 1 is it damaging parts?

[diskosteppas]

Hi all is there a test to see if the tip of my soldering iron is damaging parts while I diy synthesizer please? I am worried - my Ersa Icon 1 makes a buzzing sound when the tip, solder and component leg are in contact...

[m98]

No worries, it doesn't. The buzzing sound comes from the transformer, as the controller needs to output a lot more power while heating up the solder joint.

[diskosteppas]

OK thank you! I have wondered if it is grounded or not too.

[Ian.M]

Its very common for soldering iron bits to be grounded, as its an essential safety requirement for anything with a mains voltage heating element, and on low voltage irons fed by soldering stations with a SMPSU, it avoids significant stray voltage on the bit due to leakage current from the PSU.  Stations with a line frequency transformer can float the bit or use a high impedance ESD ground, but unless you have confirmed the bit is NOT grounded and does NOT have an undesirable AC voltage on it with respect to ground, its always best to fully disconnect the device being worked on to avoid any risk of a ground loop.   

If you need to solder a battery terminal that can't be disconnected take extreme care.  If the device cant be isolated from ground the safe way to do it is with a gas or battery portable iron, with adequate insulation on the handle for the battery voltage.

[tooki]

OK thank you! I have wondered if it is grounded or not too.

Of course it’s grounded, that is a professional tool, and ESD protection is a basic requirement for that. (That’s why any halfway decent battery-powered soldering iron has a ground connection you need to attach.)

Not to mention that the datasheet or manual would tell you that it is grounded. Or that you could test it by measuring continuity between the tip and ground.

[diskosteppas]

This is what concerned me...in that no continuity between ground of the unit and tip. Is it floating then? How can I ground it please?

[diskosteppas]

ersa manual says its hard grounded but how do I test theres no fault with my iron it was inherited after all. There is a short extract in the manual about ESD Ive attached too

[Ian.M]

https://www.ipc.org/sites/default/files/test_methods_docs/2.5.33.1.pdf
says the resistance from tip to mains plug ground pin shall be under 5.0 ohms.

Check that cold with a multimeter, and if its well under, you are probably good.  To be certain, heat up the iron to a bit hotter than your usual soldering temperature, unplug it, set up the measurement, and check it stays well under 5 ohms as it cools (i.e. doesn't go intermittently open).  You will need something tinned and sacrificial to press the tip onto so you don't cook your meter probe.  A female contact from a Molex 5.25" disk drive power connector will fit most meter probe tips nicely, and with a few inches of wire still on it, and the tip on the tinned wire end, will keep the heat well away from the probe without adding much resistance

If its close, you'll need to do the hot test documented in the linked document properly.  The test electrode is a 45mm x 23mm rectangle of copper clad PCB.

[diskosteppas]

hi thanks for this, appears from the actual iron I do get 0.2 ohm reading but from the tip itself is more like 18k...is this normal shall I buy a new tip it does look quite crusty!

[Ian.M]

Clean the back end of the tip with wire wool and see if that resistance comes down.   You may also need to clean the inside of the collar and where it seats on the threaded flange on the heating element.  Carefully brush off any fragments of wire wool before reassembly.

A high resistance doesn't matter too much if you are only working on fully isolated boards, but if the tip is generally looking rough, and can't be cleaned up, consider replacing it. 

[2N3055]

As static electricity (ESD) protection  is concerned, 18kΩ is as good as short circuit.

[Ian.M]

Yes, and although it may increase I doubt a hot metal oxide layer would ever let it get up into the tens of megaohms range, however as its not to spec, that indicates there's something wrong.   On this particular iron, it doesn't matter for stray current grounding as the element has a grounded stainless steel sheath, but on irons with a bare ceramic element, you have to consider the leakage current when hot, which can increase due to carbonised contamination as it ages, and the voltage it can develop across the tip's resistance to ground.

[tooki]

hi thanks for this, appears from the actual iron I do get 0.2 ohm reading but from the tip itself is more like 18k...is this normal shall I buy a new tip it does look quite crusty!

No, it’s not normal.
1. Test from the solder-wetted part of the tip, not the side of the tip which may have various residues. It doesn’t need to be hot.
2. Make sure the tip is tightened properly.
3. Clean the heater and the inside of the tip to make sure there’s no crud acting as an insulator.

Also, if you do get a new tip: clean it before use. I just got a few new tips, and was dismayed to discover (after the fact) that one of them had a bunch of oil left inside the barrel, which then burned onto the heater during the first use. That was a pain to clean off.

With that said, I do agree that 18kOhm is still perfectly fine for preventing damage to components.

[2N3055]

I apologize to terse statement.
Like I said 18kΩ will ensure ESD protection.

But it will not serve as protective Earth and would not protect operator from contact voltage in circuits.
Everything should work up to spec, otherwise it is basically broken. And needs repair.

But with 18k no chips were damaged by static discharge from tip.

BUT...

Sometimes DUT has static charge on itself. Coming near it might discharge DUT into tip and that current can damage the chips. That is why ESD mats and other ESD protection equipment has intrinsic resistances in MΩ range, to bleed ES charge but limiting discharge current. 

For ESD protection you need  trinity:
- DUT needs to be discharged and kept that way. -> ESD Mat on the desk that you put DUT on.
- operator  needs to be discharged and kept that way -> ESD bracelet, antistatic shoes, chairs etc.
- equipment that comes in touch with user and DUT needs to be discharged and kept that way. -> grounded equipment.

In space you can also have static dissipative floors, ionizers, air humidistats (if air is moist enough it helps).
But that is for laboratories.

In practice, ESD mat to work on, ESD bracelet on operator, and properly grounded tools and equipment is enough.
For damage you need both a charge and a discharge path. Eliminate one (or both) and you are good.

[tooki]

But it will not serve as protective Earth and would not protect operator from contact voltage in circuits.

It’s not supposed to be a protective earth.

[2N3055]

But it will not serve as protective Earth and would not protect operator from contact voltage in circuits.

It’s not supposed to be a protective earth.

If you say so. I don't have the standard (IPC in question)

But it is weird choice if that is so, because in ESD protection limiting currents is half the work. For ESD a 100k to ground is better choice than hard ground. Some soldering stations can choose ground path resistance. On some they are not hard grounded to power socket but have a banana socket that you connect to your ESD bleed point....

I would rather think it was done for some low voltage directive for contact voltage protection. But I'm no expert in this, just discussing...

[tooki]

But it will not serve as protective Earth and would not protect operator from contact voltage in circuits.

It’s not supposed to be a protective earth.

If you say so. I don't have the standard (IPC in question)

Why would IPC have anything to do with that?

Protective earth* is a human safety thing (it doesn’t have anything at all to do with protecting equipment). To be useful, a PE conductor has to be at least as thick as the conductors supplying the fault current. That certainly isn’t the case with the wire in a soldering iron handpiece.

A soldering iron isn’t normally used on energized circuits, and even if it were, then you’d need for the tip to be floating, not grounded!


I’m struggling to think of any scenario where the soldering iron tip would act as a protective earth, never mind where that would be desirable.

*PE isn’t a generic term, it is a term with a specific, defined meaning. So if you mean anything other than “the yellow-green wire used to ground metal housings to prevent them from becoming live at mains voltage” and the like, you need to use a different term.

[2N3055]

Ok.

How is soldering iron different in that regard from scope, for instance.

Fact that you should not solder on live equipment never stopped people from doing exactly that, be it from ignorance, error or equipment malfunction.

Less than 5 ohm will trip circuit braker, unless it is 100A

No to mention protective earth devices (FID)

[nctnico]

Its very common for soldering iron bits to be grounded, as its an essential safety requirement for anything with a mains voltage heating element

It is not common for soldering stations to power the heater using mains. Typically something around 24V is used through a transformer.

[tooki]

How is soldering iron different in that regard from scope, for instance.

A scope’s ground isn’t a protective earth, either. It’s grounded for signal integrity reasons, not to be protective earth. Similarly, a soldering iron’s tip is grounded for ESD protection and to eliminate stray currents, not to be protective earth.

To reiterate: the term “protective earth” has a specific, defined meaning that does not apply here. A protective earth is one designed to short mains to earth if the line conductor should inadvertently come into contact with exposed metalwork. That’s it. That’s its definition. Earthing done for any other reason is an earth, but not a “protective earth”.

An earth that shorts line to earth incidentally isn’t a protective earth.

Fact that you should not solder on live equipment never stopped people from doing exactly that, be it from ignorance, error or equipment malfunction.

Ok. So what?

Less than 5 ohm will trip circuit braker, unless it is 100A

OK. So what?

Neither of those things makes the earthing of a soldering iron tip “protective earth”.

No to mention protective earth devices (FID)

I can’t find anything under that name (fault isolation device) other than scholarly research articles. What are you talking about, and what is their relevance here?

[Ian.M]

Its very common for soldering iron bits to be grounded, as its an essential safety requirement for anything with a mains voltage heating element, and on low voltage irons fed by soldering stations with a SMPSU, it avoids significant stray voltage on the bit due to leakage current from the PSU.  Stations with a line frequency transformer can float the bit or use a high impedance ESD ground ...

It is not common for soldering stations to power the heater using mains. Typically something around 24V is used through a transformer.

I've fixed the quote for you so it isn't misleading. 

Otherwise, I think we are in violent agreement.  A mains voltage iron on a soldering station usually indicates its a nasty piece of cr@ap like the Weller WLC100.

[tooki]

Its very common for soldering iron bits to be grounded, as its an essential safety requirement for anything with a mains voltage heating element

It is not common for soldering stations to power the heater using mains. Typically something around 24V is used through a transformer.

From the context of the reply, where he explicitly mentions both SMPS and transformer-powered low-voltage irons, I’m quite certain he knows this. He was being complete because mains-powered soldering irons (not soldering stations!) — the classic fire sticks — will of course have mains-powered heaters.

[diskosteppas]

This totally helped. I get 1.3 ohms at the tip after this thankyou, it is very pitted though I will replace it.