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Registered Member #61905
Joined: Sun Nov 12 2017, 03:27AM
Location:
Posts: 23
I don't know if this is common knowledge around here, but it seems like a lot of the chineze electronics on ebay are suspect at best. They seem to have no compunction about fraud. As an example, I purchased some IRFB4227 FETs from 5 different sellers, all with good seller ratings. I received 5 different types of FETs marked IRFB4227, but none came close to the datasheet. Basically, this should be a 200v FET with a Rds of 0.02ohm. The articles I received ranged from 0.05ohm to almost 2! I tried to use one part and it died around 100v. I have a part I pulled from a board (probably genuine?) that does have a measured Rds of 0.02ohm, so I know it's not how I'm measuring them.
The ebay return policies reduce the risk of buying from these guys, but I would be suspicious of anything you get from them...
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Yes, I now don't buy components on eBay unless I can adequately test them against a known good sample. Irony: parts from dead boards are sometimes fine, have a nice pile of TV chassis here which are an ideal source for obscure components. You can typically solder them once, any more than that decreases their long term reliability but for research purposes this is fine.
The best bet when removing delicate components is an alloy like Chipquik: if you have the right tool its possible to remove parts with very little thermal stress. If you're doing a lot of them you can make a custom alloy for the specific board solder, takes a bit of time but well worth it.
Please can you post pictures of your samples, ideally with attached measurement. Thanks!
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
The internal placement and size shouldn't be an indicator nessicarilly, I think. In most cases I think they carefully grind off the existing part marks then remark them by laser or whatever.
Registered Member #54278
Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367
I have found many fake electronic components on ebay.
I bought several AD633 analog multipliers. I verified they were fake with a simple test circuit(s) compared to a several 20-year-old 633's I have. It goes on-and-on with Chinese ebay components!
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Fake/counterfeit semiconductors on ebay...
