Careful what you use to power your nixies...

[Nick]

http://www.bbc.co.uk/news/uk-27515446 

Nick

[Tidak Ada]

Weren't it only chargers and other consumer products! There are also fake transistors, IC's and electrolytes that will explode. There was for short a discussion on an Dutch electronics forum about these fake components. Give me some time, I'll dig up some photo's

 

eric

---

From: neoni...@googlegroups.com [mailto:neonixie-l@googlegroups.com] On Behalf Of Nick
Sent: donderdag 22 mei 2014 14:57
To: neoni...@googlegroups.com
Subject: [neonixie-l] Careful what you use to power your nixies...

http://www.bbc.co.uk/news/uk-27515446 

Nick

[Nick]

On Thursday, 22 May 2014 14:11:15 UTC+1, Tidak Ada wrote:

Weren't it only chargers and other consumer products! There are also fake transistors, IC's and electrolytes that will explode. There was for short a discussion on an Dutch electronics forum about these fake components. Give me some time, I'll dig up some photo's

We've had discussions on here in the past about fake transistors (big problem in the "HiFi" world), low ESR capacitors (check capacitor inside a fake case) etc. Even buying from Farnell & DigiKey etc. is no protection, as they too have been caught out in the past...

Faking stuff didn't start with "reproduction" "Genuine Roleks watches!" or fake LV handbags - its as old as history itself.

Nick 

[Tidak Ada]

Yeh, If you look at the site of James Cross Vacuum Tubes Inc. There is a page called 'Hall of Shame', showing the same with tubes [ http://www.vacuumtubesinc.com/VacuumTubesHallofShame.aspx ]

---

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Nick
Sent: donderdag 22 mei 2014 16:02
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Careful what you use to power your nixies...

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[Quixotic Nixotic]

This glowing tube is certainly real, but expensive. The electron gun at the back of a LinAc, linear accelerator. Budget about a million GB pounds for the LinAc and another million for the room and labyrinth leading to it. Then you need the trained staff so that Rory Cellan-Jones and the BBC don't get on your case.

[Nathan Campos]

Sadly there are a lot of extremely dangerous super-cheap power supplies out there. What I usually do when I receive a product that comes with a power supply that isn't from the same brand or looks a bit suspicious is open it up and check how safe it is. Most of the time the PCB is fairly safe, with a good amount of clearance and OK quality components, but usually they don't pay much attention to the mains wiring, using extremely thin and flimsy wire which can break off and short something out pretty easily, so most of the time all I have to do is apply some hot glue just to make sure it stays in place.

About the fake components, specially capacitors, it's extremely easy to spot by checking them with a LCR or ESR meter. Thankfully I still haven't had any issues with fake parts from Digi-Key or eBay.

On Thursday, May 22, 2014 9:56:36 AM UTC-3, Nick wrote:

http://www.bbc.co.uk/news/uk-27515446 

Nick

[greg...@hotmail.com]

What is the typical signature of a counterfeit capacitor ? I'm mostly concerned about the ~450V electrolytics that are commonly used for anode-supply filtering. 

In my designs, I always have a series resistor and fast-blow fuse (typically 3/8 amp; smaller ones get really expensive...) which are sized to burn-out if significantly higher current is drawn, for example an electrolytic that is breaking-down, etc.

[threeneurons]

More on those cheap chargers / adapters. A few months ago, one apparently electrocuted a woman, in Australia:

http://www.gizmodo.com.au/2014/06/please-dont-buy-cheap-phone-chargers-and-cables/

http://wonderfulengineering.com/cheap-chinese-phone-charger-electrocutes-woman-to-death/

And just to make things worse, they inflate the true ratings:

http://akihan.hubpages.com/hub/deadly-dangerous-portable-power-banks

I just bought a couple of 9V 1A switching regulators, off of eBay. They're of the same "flavor", as those that exploded in the original video. From past experience, I know the max output is pure fiction. With a 22 ohm power resistor as a dummy load, the voltage already dropped to 8.5V (385mA). This probably means that I'm already stressing the unit. I suspect the true max rating should be ~250mA. What I'm using it on, draws 35mA. It usually is powered off a battery. I'm never leaving this thing plugged in, unattended.

Maybe I should build an insulated steel test box. I need one for thermal tests anyways. Put a powered supply inside, under various loads, and see when it burns up.

[Oscilloclock]

That's absolutely terrible... And very scary about the headphones being a conduit.

I strictly use either open-frame supplies where I can get a good look at the components used, or sealed wall packs with "medical" ratings. I'm not an expert on what this category really signifies, but trust the extra expense is worthwhile.

Any opinions out there on "medical" supplies versus normal "commercial"?

Aaron

[Tomislav Kordaso]

AFAIR medical grade PSUs should conform to IEC 60601-1 safety standards. Among other things such PSU have defined earth and housing leakage currents.

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[threeneurons]

Cracked open one of those cheap adapters. They're based on the Power Integration LNK623. It needs a switching xfmr (custom) that has the primary, a feedback secondary, and at least one output secondary. Here are some photos:

To make it safe, you need to do at least two things: (1) Make sure the fuse reliably pops before the unit gets hot enough to ignite. (2) Use a split-bobbin transformer. Wind the primary, and feedback secondary on one side, and the output secondary (ies) on the other side. This will reduce the likelihood of electrocution. On this one, only 3 layers of transformer tape, and the enamel wire coating, isolate the secondary from the primary.

Here's a split bobbin transformer:

[Nick]

On Wednesday, 27 August 2014 07:18:37 UTC+1, threeneurons wrote:

Cracked open one of those cheap adapters. They're based on the Power Integration LNK623. It needs a switching xfmr (custom) that has the primary, a feedback secondary, and at least one output secondary. Here are some photos:

Interesting chip - I've added the datasheet as an attachment to this post.

You can see from looking at their application examples that the wart you opened is definitely a minimal subset - its been "Muntzed" ! (http://en.wikipedia.org/wiki/Muntzing)

Nick 

[petehand]

Split bobbin transformers are almost never used in switch mode power supplies. They give up at least 10% efficiency. The reason they're used in cheap off-AC supplies is that you can short out the scondary without popping the primary, because the coupling is that bad. The label on the bottom of that PSU has UL, CE and double-insulated symbols. If it's not a fake label, you can rely on it that the agencies are satisfied with the insulating properties of the transformer. On balance I think that's quite a good adapter.

Now THIS is what I call a cheap adapter. There's no maker's name or agency standard label on it, or even a rating plate. But I have to say it's quite nicely made, with adequate PCB clearances and protected by a fusible resistor. The low voltage side is all on the far PCB, away from the line voltage. It cost 99 cents.

On Tuesday, August 26, 2014 11:18:37 PM UTC-7, threeneurons wrote:

Cracked open one of those cheap adapters. They're based on the Power Integration LNK623. It needs a switching xfmr (custom) that has the primary, a feedback secondary, and at least one output secondary. Here are some photos:

Here's a split bobbin transformer:

[Quixotic Nixotic]

On 27 Aug 2014, at 10:18, petehand wrote:

The label on the bottom of that PSU has UL, CE and double-insulated symbols. 

Some people are still unaware that what appears to be a CE mark may in fact stand for China Export, not European Conformance.

It's a neat trick they pull there.

John S

[JohnK]

When I was a kid there were ballpoint pens around with USA on the pocket clip. Newspaper article said that 'chinese made a town' called USA so they could imprint the products.

 

John K.

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[Instrument Resources of America]

I believe that would have been "Japan" named a town USA, not China.    Ira

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[JohnK]

Oops, probably right there... it was in the 1950s/early 60s

 

jk

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[Nick]

This is a paper from Buckinghamshire Trading Standards on the risks of cheap adapters, even if they have what purports to be a "CE" mark. A test of 27 electrical chargers found that all the eight legitimately branded with a reputable name met safety standards, but none of those unbranded or with minor names did, despite bearing the  mark;

Detailed article on hazards found due to poor-quality AC adapters. "The good news for the consumer is that there appears to be a cheap charger for any make or model of mobile phone, toy or hand-held games consoles that you might require – the bad news is that it could kill you!"

http://www.buckscc.gov.uk/media/137366/60600_Booklet_proof.pdf

* For our non-UK readers, "Trading Standards" is a part of each county's local government which enforces, well..., trading standards. i.e. ensure that stuff being sold is what is is said to be, that electrical goods are safe, that local, national and international laws & regulations are enforced, that scales and measuring equipment in pubs & shops are accurate etc.

Nick

[NeonJohn]

On 09/01/2014 08:58 AM, Nick wrote:
> This is a paper from Buckinghamshire Trading Standards on the risks of
> cheap adapters, even if they have what purports to be a "CE" mark.

We looked into agency approval for our induction heaters (fluxeon.com).
What we found was startling. Unlike here in the States where the
various approval agencies (UL, ETL, etc) have their marks registered as
trademarks and thus govern how they're used, the CE mark is not
regulated. Anyone can slap a CE mark on anything. Only when questioned
by a country's regulating agency does the manufacture have to supply a
file backing up the mark. That rarely happens. Thus the CE mark has
become essentially meaningless.

John
Chief Engineer,
Fluxeon Inc.

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[MrNixie (UK)]

The only thing you can safely assume with cheap goods from China, is that the seller is interested in your dollar, not your life.

A not-foolproof test is simply to feel the weight of a charger body in your hand, when compared to a known, good (original equipment) specimin. The fake will often reveal themsleves by being lightweight - in every sense of the word. Unless you KNOW the provinance of the supply, assume any cheap Chinese charger is fake/dangerous. Do not believe ANY marking on them!

The final acid test is to break them open and inspect them, although of course there is no going back from this!

[gregebert]

For all of the above reasons, I use my own power supply designs in my nixie projects.

Even though I put a lot of protection devices in the circuit (fuses, varistors; extra margin for capacitor voltages, sheet-metal lining inside my case), I always worry about unexpected things going wrong (large voltage surge, capacitor internal short/breakdown, etc) and wonder if my design is really any safer than the el-cheapo stuff that's produced in high-volume. Knock-on-wood, nothing I've ever built in 35+ years has ever caught fire or zapped anyone.