This is freaking me out (computer related)

12 years ago

I have two circuits in my living room. On one circuit are many things, including TV, stereo, ceiling fan, touch lamp, an Oreck air purifier, and a paper shredder.

On a totally different circuit, I have my computer, monitor, printer.

When we feed paper into the shredder, the TV get snowy, and sometimes my computer beeps such as when you add/remove a USB device.

Now I got a Phillies touch lamp for Christmas. When I use the shredder, the bulbs in the lamp flicker, whether it's on or off.

Tonight, I'm using a USB scale on my computer because I was shipping out a package. My air purifier is "zapping", which it does when there's something like a cat hair caught in the filter... similar to a bug zapper. Yes, that's normal, so that's not my issue. The issue is that every time it "zapped", my USB scale RESET ITSELF.

I'm convinced the shredder and air purifier are interfering. My only question is WHY? There's no connection between the circuits that I can think of. I'm wondering if this is also why I fried my motherboard over the summer. If somehow my computer's power supply is fluctuating, it can't be good.

Thanks in advance.

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Comments (7)

Ron Natalie
12 years ago
Radio Frequency Interference. Electrical arcs are horrendously "noisy" RF generators.
brickeyee
12 years ago
"Electrical arcs are horrendously "noisy" RF generators."

We always joked that an arc could make electrical 'noise' from DC to daylight in frequency.

The shredder very likely has a small universal (brush type) motor. Whenever it runs the commutator in the motor creates arcs and RFI.

The same with any type of ionization air cleaner.
When they arc it creates a pulse of RFI noise.

The removal of most of the metal from many computer cases removes their shielding from external RFI.

If you think these small arcs are affecting things, imagine what a stroke of lightning can induce.
It is many tens of thousands of volts and thousands of amp.

If one is nearby it can actually fry almost any computer input with a length of cable connected.
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criticalmass048
Original Author
12 years ago
So then the solution to the problem is not just to put them on a different circuit, I need to get the computer physically away from the shredder, correct? Right now it's literally a foot from my CPU case.

I thought I knew about RFI, but never figured some would be coming from my shredder. The snow on the TV is understandable, but never thought it would affect a computer on a different circuit.
criticalmass048
Original Author
12 years ago
So then the solution to the problem is not just to put them on a different circuit, I need to get the computer physically away from the shredder, correct? Right now it's literally a foot from my CPU case.

I thought I knew about RFI, but never figured some would be coming from my shredder. The snow on the TV is understandable, but never thought it would affect a computer on a different circuit.
kurto
12 years ago
RFI is reduced by the square of the distance, so even a few feet may make a substantial difference. The other alternative is to provide a metal shield (or case) with a ground around either the offending or offended device.
weedmeister
12 years ago
the first character in RFI is 'R'adio. Which means it travels through the air.
yosemitebill
12 years ago
A lot of good information here and while this does sound like EMI/RFI it's important to remember the interference can be transferred through one of three methods.

1) Conductive which the interference is transmitted through signal connections, or more importantly here, AC line connections.

2) Radiated as in wireless RF transmission mentioned above.

3) Capacitive/inductive coupling which can occur in wiring/cabling running too close together or equipment placed too close to one another.

One of the most important factors in addressing interference, for all of the above methods, is good grounding. So, does your house have grounded AC outlets? If yes, you may wish to confirm the ground pin is actually connected to a true grounding conductor.

I would recommend trying plug-in EMI/RFI filters on the products being affected by the interference. Many plug-in surge suppressors, especially made for A/V & electronic equipment, have filters built-in and may prove to be helpful here.

Yes, definitely for several reasons, move the shredder away from the computer.