Samsung ETA U90EWE (fake)

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This is a 5V 2A rated usb power supply/charger.

Official specifications:
The charger was bought on ebay from fagofago

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I got it in two plastic bags.

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The charger and a usb cable.

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The adapter looks like the real Samsung adapter, but it is not.



Measurements


Samsung%20ETA-U90EWE%20load%20sweep

Output voltage is increased with load, this will compensate for losses in cables. The efficiency is around 80% and overload protection kick in at 2.2A.

Samsung%20ETA-U90EWE%20load%20test

One hour with 2A load is not problem.
The temperature photos below are taken between 30 minutes and 60 minutes into the 1 hour test.

Temp1512

M1: 55,3C, HS1: 74,2C
It looks like the transformer is getting warm.

Temp1513

HS1: 76,7C

Temp1514

M1: 60,6C, M2: 55,0C, HS1: 62,1C

Temp1515

M1: 50,6C, HS1: 64,2C

2.5ohm

There is not much noise, 26mV rms and 340mVpp. at 2A.

10ohm

At 0.5A the noise is slightly lower with 14mV rms and 230mVpp.



Tear down

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With a bit of work I could pop the lid on the charger.

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I could pull the circuit board out.
On the input side there is a fuse, ptc, inductor and a bridge rectifier.

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The blue part is a safety capacitor.

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The two green capacitors are marked 105C, very good and also needed with the temperature it reaches.

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But everything is not perfect, for 230VAC equipment there must be about 4 mm between mains and low volt side, this charger does not have enough space. If there had been some plastic wall in the slot it might have passed.


The charger passed a isolation test with 2500 volt, but failed a 5000 volt test, this makes the charger acceptable for 110VAC usage, but doubtful for 230VAC usage. With a 230VAC plug in the charger it is not acceptable.



Conclusion

When running at 2A the power supply gets hot, but it might be designed for it. Generally the performance is very good for this charger and if it had passed the 5000 volt test and there had been some plastic in the slot I would have taken it for a genuine Samsung.
But with the short isolation distance and the failed test it cannot be genuine.



Notes

The power supply was supplied by Andrej that got it from ebay dealer fagofago

Read more about how I test USB power supplies/charger