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.
Do you happen to have the brand number or more details about the adapter itself? – JakeGould – 2018-09-10T16:34:16.733
3"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 – 2018-09-10T16:54:28.563
1@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 – 2018-09-10T17:20:22.143
@Ramhound What are the known possible damages that could happen? The USB port works as it should. Do you know what was the cause of electric shocks from the chasis of my laptop minutes before the adaptor failed? – Adrian Machin – 2018-09-10T17:21:52.657
@AdrianMachin That is the label on the AC power adapter. But what about the data thing that connects to your laptop? – JakeGould – 2018-09-10T17:33:53.300
1@JakeGould The other parts don't have any information on them! – Adrian Machin – 2018-09-10T18:41:32.067
1Well, 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 – 2018-09-10T18:44:36.217
@JakeGould Right. Is it dangerous to open the adaptor to see what happened inside? – Adrian Machin – 2018-09-10T19:00:41.870
2@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 – 2018-09-10T19:03:59.363
1@AdrianMachin Regarding opening the AC adapter: Mains voltage is in absolutely no way the place to start learning electronics. Do not do anything there until you have a very solid understanding of electronics. Even with an electronics engeneering degree I do not do anything with mains voltage except connecting wires. On the top of my head I think the only thing I've ever done is resoldering a loose socket on a lcd monitor once. Unless you have a formal education for it, stay away from mains voltage. Yes, it is unlikely that you will die, but that is not a good reason to gamble. – hlovdal – 2018-09-11T22:54:34.337
@hlovdal You are one hundred percent right. Thanks for your concern. I threw it out in the bin. – Adrian Machin – 2018-09-12T10:12:44.937