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How do I buy quality external power supplies ("Adapter"/"Wall wart") from China?
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nctnico:

--- Quote from: John_doe on February 20, 2022, 10:41:02 am ---Right now my best option is to advise him to buy this somewhat external 12V module and hope the adjustment pot can take it down to 10V:
https://www.aliexpress.com/item/1005003135918220.html

But I really don't like this option. For a whole slew of reasons.

--- End quote ---
This is probably the best option. Meanwell is a well known brand and they have datasheets for their products which show the adjustment range. 10V or 10.5V won't matter much anyway so likely this Meanwell PSU will do just fine (assuming it actually is an original PSU and not a fake one).
Wallace Gasiewicz:
If I need a wallwort, I go to the Salvation Army Store.  I then look for a heavy old one with the correct volts and proper connector pin out. (pos or neg center ??)
I have never been to Israel. Perhaps you have some second hand or "charitable" stores like "Salvation Army"
CB or other electronic repair stores have all sorts of 'junk' lying around, Perhaps there is one near you.

The heavy wallworts or in line PS usually have an AC transformer rather than SMPS design. The device powered usually breaks rather than the PS, so there are lots lying around.
RadioShack used to have a small "universal" PS that had a switch for different volts and connectors for different size and polarity devices. It is a good PS.

It is extremely unfortunate the new devices are frequently of poor design and function.from China,
Even if someone bought a particularly nice one there is no guarantee you will receive the same quality, or even the same device.

I am in US so our AC voltages are different, of course.
BeBuLamar:
Actually I would want to know what kind of device he uses the walwart for. If it's something valuable it's worth the money to buy a good power supply.
wraper:

--- Quote from: Zero999 on February 24, 2022, 09:01:34 am ---
--- Quote from: wraper on February 21, 2022, 10:46:57 am ---
--- Quote from: SmallCog on February 21, 2022, 02:18:26 am ---Basic options:

1) Buy from online marketplaces such as ebay/ali/bangood/wish etc. and roll the dice that you'll get what you ordered and it will be safe

2) Buy the above with the skills/experience/knowledge to open the device, assess its safety, and either make the appropriate alterations or dispose of it and try again.

--- End quote ---
Unfortunately that is not enough. A lot of them may look OK on a first glance, however transformer may easily lack any serious insulation or QC even if construction is somewhat decent. Only Hi-pot test will show if its electrically safe or not.

--- End quote ---
I wouldn't even trust a hi-pot test for a dodgy, unknown transformer. It might pass, but that doesn't mean anything. If they used crappy insulation and too thin wire, it might get hot, melt and arc over during normal operation. The only way is to take a few to pieces, look at how it's constructed an the quality of the materials used.

--- End quote ---
I didn't call the Hi-pot test a panacea, I said that teardown by itself is not enough. Teardown without a high pot test will make apparent only the most obvious offences.
ve7xen:

--- Quote from: nctnico on February 24, 2022, 11:50:46 am ---
--- Quote from: John_doe on February 20, 2022, 10:41:02 am ---Right now my best option is to advise him to buy this somewhat external 12V module and hope the adjustment pot can take it down to 10V:
https://www.aliexpress.com/item/1005003135918220.html

But I really don't like this option. For a whole slew of reasons.

--- End quote ---
This is probably the best option. Meanwell is a well known brand and they have datasheets for their products which show the adjustment range. 10V or 10.5V won't matter much anyway so likely this Meanwell PSU will do just fine (assuming it actually is an original PSU and not a fake one).

--- End quote ---

It'd be a fine option from a controlled supply-chain seller, sure. On Ali I would say the chance of getting a counterfeit MeanWell product approximates 100%. It's been a popular brand for counterfeiters for ages. Stuff like this I just accept that I will need to either scavenge it from discarded consumer products or purchase it from a proper distributor, there doesn't seem to be a reasonable middle ground.

I really wish you could trust trustworthy brands on Ali or eBay, but you just can't. I've even got counterfeits of some industrial stuff I wouldn't have thought has a large enough grey market volume to bother with, like specific SKUs of Omron temperature controllers and uncommon-brand SSRs. Felt a bit safe in that assumption that the effort involved in cloning the front panels, making fake packaging and documentation and sometimes plastics wouldn't be worth it to make a few pennies profit per unit, but nope, still counterfeit.

There are trustworthy Chinese distributors and manufacturers too of course, but I don't think as a random English-speaking consumer we really have reliable access to them, and they probably aren't interested in selling single units. Maybe something LCSC will stock in the future...

Edit: I should add that AliExpress does attempt to provide some assurance of the company's information if you go to the store Business Information link, though I'm not sure they verify it, but it can sometimes tell you if you're dealing with a fake. For the example store, 'established 2019-04-12' doesn't really jive with someone representing themselves as connected to MeanWell, and the translation of the business scope suggests the company is supposed to be trading baby supplies. Nor does the name include '明緯/明纬' (MeanWell). So rather a few red flags.

If you look at the same page for Rigol's official store, for example, the information does all line up with what you'd expect.
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