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I bought a Chinese SATA/IDE to USB converter that has no brand name. Specs for the power adapter are:

  • Model: SY-002-5-12
  • Input: 100-240 VAC, 50/60Hz, 0.8A
  • Output: 12V and 5V both 2A

After connecting a 3.5" SATA HDD to my laptop via the converter, I sometimes get electric shocks from some parts of the laptop case.

The converter uses an AC adaptor with a cable like this:

enter image description here

That uses 4 wires for powering an HDD. Some say that it would be dangerous for HDD because of the lack of one wire.

Is it dangerous to use this converter? Why do I get electric shocks? Did I damage my laptop with this converter and small electric shocks?

EDIT: Now shortly after I'm writing this, the adapter made a spark/bang noise and went off. It doesn't turn on again. How can I tell if it damaged my laptop through adaptor > HDD> USB?

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    "Is it dangerous to use this converter?" - Yes, it absolutely is dangerous to use the adapter. "How can I tell if it damaged my laptop through adaptor>HDD>USB?" - Honestly, you can't tell, but if the USB port works then there is a good chance no damage was done. You should avoid generic parts in the future, they are cheap, for a reason. – Ramhound Sep 10 '18 at 16:54
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    @JakeGould There's a label on it with the following info. Model: SY-002-5-12, Input: 100-240 VAC, 50/60Hz, 0.8A, Output: 12V and 5V both 2A. – Adrian Machin Sep 10 '18 at 17:20
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    @JakeGould The other parts don't have any information on them! – Adrian Machin Sep 10 '18 at 18:41
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    Well, here is my advice: For $10 a pop you can buy 3-4 of these things from different manufactures of varying quality and see what happens. Or for $30 to $40 you can buy one item from a decent manufacturer that stands by what they sell and and good quality. In this case, if the AC adapter failed, that is not a big deal. I bet the USB cable with the data connections are fine. So toss the AC adapter, and the keep the data dongle. – JakeGould Sep 10 '18 at 18:44
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    @AdrianMachin The AC adapter? You won’t figure out anything other than see burned components. AC adapters are not difficult items. You will learn nothing of value by opening one up now. Just toss it. – JakeGould Sep 10 '18 at 19:03
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The pictured adapter is not at fault... The missing wire is the 3.3v supply, and most hard drives can operate without it.

It will be the mains to Molex adapter that is dangerous.

If it was still working I'd suggest that you try unplugging your laptop from power (thus running on battery) - the "shocks" will likely go away.

Unfortunately too many cheap power supplies have this behaviour.

The fact that the supply has since died doesn't bode well either... Put it in the bin. Again, many cheap supplies aren't built to sensible standards, especially if they are imported or overly cheap.

It's going to be very difficult to determine if any damage has been done to your laptop or the hard disk. Try the USB port - if it works, then great.


I'd like to know what was the cause of electric shocks from laptop chassis minutes before the adaptor failed?

Fundamentally, the cause of the electric shocks is due to two things:

  • A potential difference (voltage) between two conductive items (e.g: laptop chassis and hard disk)
  • An ability to source / sink current between these items

It's a complex topic, and not really suited to Super User... but it can be thought of like a ground loop.

It could be very well be caused by poor Class-Y capacitors, as discussed in this answer: https://electronics.stackexchange.com/a/216967/142242


What are the possible known/common damages that could have happened?

Ultimately a "bad" power supply like this can cause issues ranging from "almost nothing", through sparks, to death.


Do you recommend opening the adaptor to see and report its insides for further investigations?

No - throw it away.

The best you can do is report the issues to the seller. Due to the unbranded nature and flooding of the market with such supplies, there probably isn't anyone you can "go after" or even report it to.

  • Thank you. The USB port works fine as of now. I'd like to know what was the cause of electric shocks from laptop chassis minutes before the adaptor failed? And what are the possible known/common damages that could have happened? – Adrian Machin Sep 10 '18 at 17:25
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    I forgot to say that the small zaps that I got were coming from metal parts like USB ports since my laptop chassis is made of plastics. The whole incident happened during a file movement task which luckily finished before the adaptor failed. So it sounds like a grounding issue rather than a high voltage across the USB port of my laptop. Do you agree? And do you recommend opening the adaptor to see and report its insides for further investigations? I'm worried if I damaged my laptop so I'm trying to find out what exactly happened and if there was high voltage across my USB port. – Adrian Machin Sep 10 '18 at 18:49
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    @AdrianMachin “And do you recommend opening the adaptor to see and report its insides for further investigations?” Don’t rip apart anything else. It all sounds like a bad grounding issue from the AC adapter that blew. The USB dongle would not have caused that. If you are now worried about your laptop, my best advice is to simply test the USB ports and if they work, you are fine. No need to do anything else. – JakeGould Sep 10 '18 at 19:00
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    @JakeGould It may not necessarily be the AC adapter that had the grounding problem. Just the fact that the power supplies are different is sufficient to possibly have a potential difference between ground planes (I've got two laptops on my desk right now that will form a ground loop if you touch their metal chassis together, simply because one has a ground plane that's ~1.5V higher potential than the other, they both work perfectly fine though). – Austin Hemmelgarn Sep 10 '18 at 19:43
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    @PeterCordes No. They were plugged into the same outlet. – Adrian Machin Sep 11 '18 at 13:23

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