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 Any wonder some SMPS distribute tons of RFI?
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 Return to top of page · Post #: 16 · Written at 11:22:02 AM on 29 August 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2013

Does anyone remember the Apple 2 computers that schools used to have hundreds of?

RFI from those things was so bad that my 2 way radio on 77.36MHz would break mute anywhere within half a kilometre of a school.


 
 Return to top of page · Post #: 17 · Written at 12:14:13 PM on 29 August 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 923

Ten years ago you could import electronic equipment into this country by a certain category, so long as you provided "proof" that the equipment complied with some standard or other. There was no need to have such category equipment "tested" for compliance, even if there is such a body left in this country that could do that. I bumped into guys that used to work for compliance labs and standards that had shut down.
All you had to do was state the rubbish you were bringing in applied to that category (cant remember the categories) and send somebody in the government the paper work with the right numbers on it and all was OK.

Thirty years ago when I manufactured stuff it had to comply with any number of Australian Standards set out by the Government so it complied with safe practice and did not kill anybody.

I guess all of that has gone by the board and anybody can bring in stuff that catches on fire or does not work (like washing machines and plug packs and wanker phones) and "consumer affairs" seems to be ruling department! Amazing.

I'm way out of touch, possibly some one like Ian R may have a handle on the current scene.
What bodies still exist that actually do tech testing?

Fred.


 
 Return to top of page · Post #: 18 · Written at 2:27:09 PM on 29 August 2020.
Trobbins's avatar
 Location: Melbourne, VIC
 Member since 11 July 2012
 Member #: 1179
 Postcount: 44

There are circuit assemblies that can be sold that don't have to comply. Many smps modules fall in to that end use case. It is up to the final product manufacturer, who wants to sell the product to show compliances, and so that manufacturer may or may not have to add in additional filtering, or shielding, to gain final compliance.

In that situation, the smps manufacturer may provide certain test data, but that test data only relates to their assembly, not the final product.

Kit assembly type equipment probably falls through the cracks, especially if it a magazine construction project where the smps may be defined as ' we used type x for our prototype', but there is no onus to use type x and kit sellers could easily substitute other parts, or diyers could cobble together whatever they could. Any such final use by a diyer that causes a comms problem may then fall under a country wide legislation that no one can cause a certain type of comms degradation (eg. the government would certainly send out the inspectors if all nearby TV's lost sync).

In that situation, GTC's young London guy is totally at fault imho (and he may have easily thrown away any note on supplied documentation that was a warning of such issue).


 
 Return to top of page · Post #: 19 · Written at 5:51:24 PM on 29 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6172

In that situation, GTC's young London guy is totally at fault imho

Maybe it's not clear from what I have said, but the PSU was a modular unit sold complete, similar to this:
https://www.maplin.co.uk/kolink-core-series-500w-80-plus-certified-power-supply-5999094001312

Plug and play as far as a PC builder is concerned. From what I gather, the unit in question sold for around £20, so bottom of the market.

As a side note, the PSU I linked to is stated as 'certified' but that's for efficiency not EMC.

"80 Plus is a voluntary certification program intended to promote efficient energy use in computer power supply units (PSUs). Launched in 2004, it certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load, and a power factor of 0.9 or greater at 100% load."


 
 Return to top of page · Post #: 20 · Written at 8:57:56 AM on 30 August 2020.
Trobbins's avatar
 Location: Melbourne, VIC
 Member since 11 July 2012
 Member #: 1179
 Postcount: 44

Does that mean the photo in the original post was with a cover taken off of the power supply module, and the power supply module had an IEC mains connection and external labelling with power supply ratings and CE marking etc ?


 
 Return to top of page · Post #: 21 · Written at 9:23:54 AM on 30 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6172

Does that mean the photo in the original post was with a cover taken off of the power supply module, and the power supply module had an IEC mains connection

Yes, it was opened and photographed by the hams who tracked it down.

and external labelling with power supply ratings and CE marking etc ?

Can't speak to what sort of labelling it had or not.


 
 Return to top of page · Post #: 22 · Written at 10:05:36 AM on 30 August 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4506

There was a case here some years ago, where a Refrigerator was generating RFI & affecting the internet. As noted several times I did send back two LED floodlights for wiping out everything AM & FM & the NBN box is no better.


 
 Return to top of page · Post #: 23 · Written at 9:50:05 AM on 2 September 2020.
Sirwin's avatar
 Location: QLD
 Member since 10 April 2009
 Member #: 465
 Postcount: 106

I once had a computer with its power supply like that. I couldn't listen to the (MW) radio with the computer on, and the interference was bad even with the computer "off". I complained about it to the retailer but they didn't want to know. Just out of warranty, the PSU failed; I repaired it and found the common mode choke and associated capacitors missing. I put them in, and problem fixed! Interference hardly noticeable. So they do make a difference.


 
 Return to top of page · Post #: 24 · Written at 11:06:50 AM on 2 September 2020.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 406

That stands to reason.
With those parts omitted the power lead and house wiring become an RF transmitting antenna.


 
 Return to top of page · Post #: 25 · Written at 12:25:47 PM on 2 September 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6172

^ and street wiring makes an even better antenna.


 
 Return to top of page · Post #: 26 · Written at 8:24:58 PM on 2 September 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4506

Actually miles of three phase wire makes a fabulous antenna: That's why there are permanent filters here, in several places, getting it out of the mains.


 
 Return to top of page · Post #: 27 · Written at 12:19:57 PM on 4 September 2020.
BurntOutElectronics's Gravatar
 Location: Alexandra, VIC
 Member since 2 October 2019
 Member #: 2392
 Postcount: 226

Does anyone still have a Apple II computer?


 
 Return to top of page · Post #: 28 · Written at 1:54:48 PM on 4 September 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4506

Best I can do is two Apple trees.


 
 Return to top of page · Post #: 29 · Written at 10:16:52 PM on 4 September 2020.
BurntOutElectronics's Gravatar
 Location: Alexandra, VIC
 Member since 2 October 2019
 Member #: 2392
 Postcount: 226

Well Mark unfortunately I'm more into the vintage silicon apple!
Just not the same taste from one of those analogue apples you discribe!


 
 Return to top of page · Post #: 30 · Written at 7:18:14 PM on 5 September 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 712

Enough to give you the pip.


 
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