Fun text about investigating 12v ac/dc adaptors

[William Gaatjes]

It is not really pc related, but you may find this interesting to read :

http://www.edn.com/design/pc-board/4441830/Teardown--12V-AC-adapters---The-Horror

It is about the disturbing trend of repackaging used printed circuit boards into "new" cases...
Yay for recycling ?

 

[Jeff7]

Oh look, CapXon capacitors again. Bleh.

Delta unit: A real Nippon Chemi-Con capacitor there? Nice.


Those weren't so bad as far as cheaping-out goes on these things. Some of them can be dangerous: Poor isolation, regular ceramic caps used in place of Class X or Y caps, lousy regulation, no overload protection, thermal problems.....

A laptop supply here at work failed and was found to be too hot to touch.
The transformer had a plate of metal attached to it with what looked like silicone caulk. The plate was then stuck to the inside of the plastic shell. Maybe it was heat transfer compound, but I don't think that stuff works too well if it's gobbed on at 0.1" thick with numerous gaps and voids.



Not a power supply...:
EEVBlog covered a really dangerous water-heating wand recently.
It's just a plastic stick with a plug and two metal plates in it that are tied directly to hot and neutral, which the manufacturer says is to just be inserted into a pitcher of water. The resistance of the water itself results in a heating effect.
(Skip ahead to 6:50 to see it turned on.)

 

[Red Squirrel]

lol this is rather interesting... seems it would be more work to do this than to come up with a design that is consistent and just get it done. I guess these were probably one ofs. I always laugh when I see capxion and other crappy brands of capacitors too. The Rubycons or Nippon Chemicon or even Nichicon arn't that much more expensive.

And that water wand is hilarious. It's crazy to think this is something that actually makes it out to market. Definitly no UL or CSA approval there. I don't even think ETL would touch that.

There's a channel called bigclovedotcom, he reviews lot of cheap chinese stuff, it's actually pretty funny some of the stuff they put out, but every now and then there's actually something half decent too.

 

[William Gaatjes]

Oh look, CapXon capacitors again. Bleh.

Delta unit: A real Nippon Chemi-Con capacitor there? Nice.


Those weren't so bad as far as cheaping-out goes on these things. Some of them can be dangerous: Poor isolation, regular ceramic caps used in place of Class X or Y caps, lousy regulation, no overload protection, thermal problems.....

A laptop supply here at work failed and was found to be too hot to touch.
The transformer had a plate of metal attached to it with what looked like silicone caulk. The plate was then stuck to the inside of the plastic shell. Maybe it was heat transfer compound, but I don't think that stuff works too well if it's gobbed on at 0.1" thick with numerous gaps and voids.



Not a power supply...:
EEVBlog covered a really dangerous water-heating wand recently.
It's just a plastic stick with a plug and two metal plates in it that are tied directly to hot and neutral, which the manufacturer says is to just be inserted into a pitcher of water. The resistance of the water itself results in a heating effect.
(Skip ahead to 6:50 to see it turned on.)

That water heater is scary. If people do not know, life ending situations can occur.

 

[Jeff7]

lol this is rather interesting... seems it would be more work to do this than to come up with a design that is consistent and just get it done. I guess these were probably one ofs. I always laugh when I see capxion and other crappy brands of capacitors too. The Rubycons or Nippon Chemicon or even Nichicon arn't that much more expensive.

It's not cheaper if you don't have an engineering department.
Let someone else do all the R&D work, then just repackage their scraps. Saves you money, and it's all locked away in a sealed black box that might not catch fire. It's rebadged and likely in another country, so you're pretty well insulated against any kind of consequences when/if it fails.

And that water wand is hilarious. It's crazy to think this is something that actually makes it out to market. Definitly no UL or CSA approval there. I don't even think ETL would touch that.

There's not much to stop them from putting the UL logo somewhere on the package though.

There's a channel called bigclovedotcom, he reviews lot of cheap chinese stuff, it's actually pretty funny some of the stuff they put out, but every now and then there's actually something half decent too.

Do they just do electronics, or anything and everything?


Decent Chinese-made stuff:
Many semiconductors are only made in China, so you can get good ST Micro or On Semiconductor or Microchip or many other brands made there. As long as the parent company keeps tight control of quality, you can get good stuff.
Fenix flashlights have also been good to me.

 

[William Gaatjes]

When it comes to that water heater, just think about it that the net voltage in China is 220V/50Hz.


https://www.travelchinaguide.com/essential/electricity.htm


On a side note, i never knew Japan had just 100V net voltage. :hmm:

The placement and shape of the holes in the socket for Chinese net voltage sure is funny (stereotype). :biggrin:

 

[Jeff7]

When it comes to that water heater, just think about it that the net voltage in China is 220V/50Hz.


https://www.travelchinaguide.com/essential/electricity.htm


On a side note, i never knew Japan had just 100V net voltage. :hmm:

The placement and shape of the holes in the socket for Chinese net voltage sure is funny (stereotype). :biggrin:

I think he did test it at 220VAC.

....close. 245VAC on his tester. 1.2kW.


I wonder what those metal contacts are made of, and what they might be pushing into the water?

"They're testing for lead in solder now. What are we going to do with all this leftover stock? :hmm:"