Dave is absolutely correct. I’ve seen the same issues with Chinese SMPS designs
used by my clients.
Here is an article I wrote comparing real Apple power modules versus Chinese
clones.
https://www.signalintegrityjournal.com/blogs/17-practical-emc/post/2736-apple-versus-clones-the-risk-in-using-counterfeit-power-modules
<https://www.signalintegrityjournal.com/blogs/17-practical-emc/post/2736-apple-versus-clones-the-risk-in-using-counterfeit-power-modules>
Cheers, Ken (WA6TTY)
________________
Ken Wyatt
wyattphoto@mac.com
> On Feb 9, 2023, at 10:00 AM, rfi-request@contesting.com wrote:
>
> Kurt, you certainly nailed the typical sequence of events. For those of
> you who have never been in the designer or retrofit shoes of the engineers,
> take Kurt's contribution as gospel! It's real as described, and many times
> even worse with problems being simply swept under the rug or directed by
> management to be ignored. And W9IP's observation is also gospel. It's all
> about money these days, not quality or obeying the radiated emission laws.
>
> There is another enemy in the stewing pot of RFI soup: the contract
> manufacturer. The source company may come up with a fix for something and
> passed one or three units through regulatory testing, but when passed on to
> the CM, most of the EMC/RFI components are removed and jumpers installed.
> Typically the RFI/EMC components contribute nothing to the performance of
> the product only add cost. So, the CM doing what CMs do, reduce cost, the
> components are removed. I've seen this so many times in the past 20
> years. China is particularly guilty of this practice.
>
> Yet another ingredient to the stewing pot of RFI soup: China. I seriously
> doubt there are but 1% of SMPSs designed and built in the US. China is
> pretty much the single source of SMPSs and SM controllers in all their
> incantations. We all are aware of where China stands wrt EMC/RFI - they
> don't care and cheat at every possible opportunity.
>
> Yet another ingredient to the stewing pot of RFI soup: Our very own FCC.
> Those SMPSs from China sail through Customs as a "component" with no
> attention paid to regulatory testing. And further, they are installed in
> all our appliances. And.....our very own FCC exempts appliances for any
> EMC/RFI evaluation other than to point out "to use best engineering
> practices"
>
> No wonder SMPSs in all their themes and variations are an ongoing and
> increasing problem.
>
> Dave - W?LEV
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