Reducing interference from dodgy MacBook charger

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JoshWright

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#1224553 29-Jan-2015 09:37

sir1963:
JoshWright:
Behodar:
JoshWright: About 18 months ago I replaced the original 85W MagSafe charger that broke with a brand new one on Trade Me that was supposedly genuine, but I've always had my suspicions that it's fake or partially fake.

You really need to watch out on Trade Me; I bought a "genuine" Apple battery and received a fairly good fake. If I didn't have the original Apple one to compare with then I probably would've trusted it, but the label text was in a slightly different font. That could've just been a tooling change at the factory, but the serial number reported by System Profiler didn't match the one on the label - something that I wouldn't have even checked if I didn't have my suspicions in the first place!

Just had a look in System Profiler, must be a fake, the serial number and other values are just blank

AC Charger Information: Connected: Yes ID: 0x0000 Revision: 0x0000 Family: 0x0000 Serial Number: 0x00000000 Charging: Yes

How long ago did you buy it and did you use "Buy Now" ?
If so, use the consumer guarantees act/fair trading act etc to get your money back as the product was clearly NOT what was advertised.

I bought it in April last year using Buy Now, so I sent them an email last night quoting parts of the CGA saying it's not as advertised to try see what they can do.

Lenovo

Shop now for Lenovo laptops and other devices (affiliate link).

Niel

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#1227764 2-Feb-2015 14:26

Even buying chargers in shops do not guarantee compliance/safety.

http://www.esv.vic.gov.au/Portals/0/Alerts-and-Recalls/usb2.htm

You can never have enough Volvos!

SepticSceptic

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#1250452 3-Mar-2015 17:58

Very good dissertation on various ipad / etc chargers - noise, safety, etc

http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html

richms

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#1250468 3-Mar-2015 18:11

I wouldnt get anything charger like off a random importer. There is too much crap for sale, and there have been no cases of people being properly done for selling these things other than things like clearly non compliant xmas lights and really junk travel adapters.

Trademe appear to stick their head in the sand and pretend that if it has a NZ plug on it then its fine to sell. Not looking at if it really is a AS3112 compliant plug or just some chinese one.

Seller has to provide a SDOC on request for devices they sell. Ask for one. If they dont provide one to you then report them to energy safety, which you can find how to do on the ministry of economic development website.

Trademe sellers arent even bothering to get faked test certs and prepare a SDOC for the items, they just get a box lot sent over from china and sell them. The person buying for them in china has no clue and will get the cheapest ones.

There are perfectly legitimate power supply makers in the markets like meanwell right beside places selling copys of their designs.

Richard rich.ms

Niel

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#1250492 3-Mar-2015 18:46

SepticSceptic: Very good dissertation on various ipad / etc chargers - noise, safety, etc

http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html

Interesting but dangerous article. SMPSUs very seldom suffer from 100Hz/120Hz hum due to how they work - diode and capacitor on output, large bulk capacitor on input, high frequency switch and high frequency transformer in between which does not work so well at low frequency... Testing is also only regarding conducted noise, no mention about radiated noise (nor conducted or radiated immunity) which can cause much worse issues. But it does get the point across regarding counterfeit power supplies.

You can never have enough Volvos!

richms

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#1250501 3-Mar-2015 19:05

believe me, the cheap ones do have 100Hz output on them because real capacitors cost more money than the POS's they put into them. The testing of the designs seem to be "does a phone show that its charging when plugged in" and no more. They usually dont have an actual SMPS chip and just have an oscilator with some form of feedback from the output either via an optocoupler or in one I saw there was just a high value resistor from the output over to the input side.

Forget anything like seperate windings on the transformer, you will only have a few microns of enamel between you and the mains. Probably cheap flakey enamel just about to crack right thru.

Richard rich.ms

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