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Re: Glass sided computer cases

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On 7/01/2025 7:18 am, Computer Nerd Kev wrote:
> Mighty Mouse <"squeak!"@thecheesefactory.com> wrote:
>>
>> Many cases now have glass sides. but what about radiation from the
>> components inside? cases were all metal to shield radiation.
> 
> Well the fronts always tended to be plastic, so a clear plastic (or
> I guess top-end models _might_ use glass) side isn't that much
> different for shielding.
> 
> Laptops are already unshielded though (mine drowns out weak FM
> radio stations when it's running), and EM radiation from poorly
> shielded USB cables (and before that serial cables) are well
> known in the form of "mouse noise" picked up by PC speaker cables
> running nearby.
> 
> The computer world is already a mess of EM noise, so I don't think
> clear case sides change much. Users could always fit some wire mesh
> inside the case window if concerned about it anyway.
> 
> I do quite like this approach to a clear PC case:
> https://hackaday.com/2019/06/10/somethings-fishy-about-this-computer/
> 
Back in 1980, we were replacing an IBM370 with a Fujitsu M180 at 
National Library. During the changeover both system were run in parallel 
to the point where every desk that had an IBM terminal, had a new 
Fujitsu one as well. A problem arose when the Fujitsu terminal was 
switched on, the IBM terminal stopped working. This seemed reasonable to 
us 🙂 but the customer demanded a fix.

After a bunch of other people had been unable to fix the problem, I was 
asked to take a look. The terminals were completely dumb, all the smarts 
were in the controller. Each controller ran, I think, 16 terminals with 
a coax cable between. One thing that I noticed was that the signal 
return was not ground, the two were connected by a capacitor at the 
controller end. I tried fitting a bigger capacitor and bingo - problem 
solved.

The Library's chief engineer asked me to make a report as to what the 
original problem was. I said electro-magnetic radiation between the long 
coax cables that were run in close proximity. He nearly exploded at that 
"You can't say electro-magnetic radiation" he said "The whole place will 
walk out". So we agreed to just say interference.

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Glass sided computer cases Mighty Mouse <"squeak!"@thecheesefactory.com> - 2025-01-06 11:49 +1100
  Re: Glass sided computer cases Petzl <petzlx@gmail.com> - 2025-01-06 16:06 +1100
    Re: Glass sided computer cases MightyMouse <"squeak!"@thecheesefactory.com> - 2025-01-07 15:11 +1100
  Re: Glass sided computer cases Xeno <xenolith@optusnet.com.au> - 2025-01-06 18:23 +1100
    Re: Glass sided computer cases Daniel70 <daniel47@nomail.afraid.org> - 2025-01-06 19:36 +1100
    Re: Glass sided computer cases MightyMouse <"squeak!"@thecheesefactory.com> - 2025-01-07 15:12 +1100
  Re: Glass sided computer cases "Gary R. Schmidt" <grschmidt@acm.org> - 2025-01-06 22:35 +1100
    Re: Glass sided computer cases Xeno <xenolith@optusnet.com.au> - 2025-01-07 00:16 +1100
    Re: Glass sided computer cases MightyMouse <"squeak!"@thecheesefactory.com> - 2025-01-07 15:14 +1100
  Re: Glass sided computer cases not@telling.you.invalid (Computer Nerd Kev) - 2025-01-07 07:18 +1000
    Re: Glass sided computer cases Keithr0 <nothing.to.see@here.com.au> - 2025-01-07 11:58 +1000
      Re: Glass sided computer cases Mighty Mouse <"squeak!"@thecheesefactory.com> - 2025-01-07 16:57 +1100
    Re: Glass or perspex sided computer cases Mighty Mouse <"squeak!"@thecheesefactory.com> - 2025-01-07 16:54 +1100
      Re: Glass or perspex sided computer cases not@telling.you.invalid (Computer Nerd Kev) - 2025-01-08 06:54 +1000
        Re: Glass or perspex sided computer cases MightyMouse <"squeak!"@thecheesefactory.com> - 2025-01-08 11:28 +1100
          Re: Glass or perspex sided computer cases Computer Nerd Kev <not@telling.you.invalid> - 2025-01-08 11:12 +1000
          Re: Glass or perspex sided computer cases Keithr0 <nothing.to.see@here.com.au> - 2025-01-08 13:38 +1000
  Re: Glass sided computer cases Petzl <petzlx@gmail.com> - 2025-01-15 12:34 +1100

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