Author Topic: Chinese switch mode power supply  (Read 545 times)

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Offline Lango1818Topic starter

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Chinese switch mode power supply
« on: November 12, 2024, 10:19:57 am »
Just purchased two 240/48 volt 10 amp switch mode power supplies off Ebay I will repot further on the extremely bad workmanship soon. However I was wondering what authority one could send a complaint to about the unsafe nature of these supplies.  One supply had a resistance of 8 ohms between earth and the main metal body and 200 ohms between the metal lid and earth. On investigation I found the circuit board to be a nightmare, with hr solder joints everywhere. Some components not even properly soldered in, I could move the output choke and capacitors making the wires slide in and out of the circuit board.
I have repaired both power supplies and now have less than 0.1 ohms between earth and the metal case. They also appear to work as they should.
 

Online wraper

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Re: Chinese switch mode power supply
« Reply #1 on: November 12, 2024, 10:28:54 am »
These often also have an e-waste mains side bulk electrolytic capacitor with a new shrink wrap to make it look less obvious it's salvaged trash.
 

Offline fzabkar

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Re: Chinese switch mode power supply
« Reply #2 on: November 12, 2024, 10:54:18 am »
Just purchased two 240/48 volt 10 amp switch mode power supplies off Ebay I will repot further on the extremely bad workmanship soon. However I was wondering what authority one could send a complaint to about the unsafe nature of these supplies.  One supply had a resistance of 8 ohms between earth and the main metal body and 200 ohms between the metal lid and earth. On investigation I found the circuit board to be a nightmare, with hr solder joints everywhere. Some components not even properly soldered in, I could move the output choke and capacitors making the wires slide in and out of the circuit board.
I have repaired both power supplies and now have less than 0.1 ohms between earth and the metal case. They also appear to work as they should.

In Chinese manufacturing, the customer is the final phase of the quality control process.
 
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Offline Lango1818Topic starter

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Re: Chinese switch mode power supply
« Reply #3 on: November 12, 2024, 05:25:02 pm »
I guess so long as Blackrock/Vanguard are making a profit they do not care about quality control
 

Offline Poroit

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Offline Zero999

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Re: Chinese switch mode power supply
« Reply #5 on: November 13, 2024, 08:17:34 am »
Why did you repair it? It isn't your job. Report and return it. The seller shouldn't be allowed to get away with selling junk.
 

Offline Lango1818Topic starter

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Re: Chinese switch mode power supply
« Reply #6 on: November 13, 2024, 03:18:35 pm »
No I agree they should not be allowed to get away with selling junk. The seller has given me a full refund including post. No doubt they will continue to sell these items on E-bay. I repaired it so I could get a feel for the extent of the poor quality. I have also found the power semiconductors (NPN 2sc3022 and high speed diode) are all second hand recovered from junked equipment. Somebody else said the capacitors are often old and just have a new sleve on them to make the look new. At this point with up to 15% of the items I have bought from China being over rated, badly built and or plain fake nothing would surprise me.  :-//
 


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