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electrical interference

stinkfoot

Standard Member
Hi! I'm getting interference on my tv whenever I have my laptop plugged into the same outlet. I can't move the laptop since it feeds into the tv thru a vga to composite video converter. my tv system is all coax and composite connections (I have -gasp- 3 vcrs - I live remote enough that my county actually still has analog over air tv signals).

any suggestions on eliminating that interference other than the obvious (upgrade from my ghetto gear - which I'm working on saving up towards)? It's not as bad as vacuum cleaner interference, but still a significant loss in quality.

Thanks!
core
 

Chris Muriel

Distinguished Member
Have you temporarily tried with the laptop PSU (power supply unit) plugged into a different outlet via a mains extension/distribution lead ?
If you run the laptop off its batteres (mains PSU not powered up) does the interference go away ?
Have you got a spare laptop PSU (my Dells have 2 supplied) to see if the PSU is faulty.
Ferrite rings around the mains cable may lessen the effect. Clip-on Ferrites : Ferrites : Maplin Electronics

Related interference issue with more advice on ferrite rings : http://www.avforums.com/forums/dab-digital-radio-fm-radio/1400753-led-driver-interference-fm.html
 

stinkfoot

Standard Member
when I unplug the laptop (and operate on battery), the interference does go away. I briefly tried plugging into another outlet (on the same house circuit) through a standard 3 prong extension cord. might have lessened the effect, might not. I'll have to do a few back and forth comparisons when I get home from work to say for sure. no backup PSU.

what is a mains extension/distribution lead? are ferrite rings just tubes that click around the PSU cord? How likely do think that solution is? Is that something I can get at a best buy type of store or more of a radio shack?

thanks!
 

Chris Muriel

Distinguished Member
Are you based in North America ?
I ask this because Radio Shack don't exist in Europe anymore and BestBuy are closing down in UK.
Yes, RS do carry them and they go around the cable.
Here are some mains distribution leads Mains Distribution Outlets
You can even get them with some RF interference suppression built in (at a price).
It looks like your interference emanates from the PSU, possibly travelling via the mains wiring.
 

stinkfoot

Standard Member
Chris,

you nailed the source of the interference dead on. Last nite I tried a backup power supply borrowed from work and no interference, so problem solved.

and yes....North America (USA specifically). I didn't realize that radio shack was gone from Europe. unfortunate, since even though they are becoming cell phone dominate, you can still get resistors, caps, and most other common electronic circuit components.

Thanks again for your responses.
 

Chris Muriel

Distinguished Member
Glad we got to the bottom of this and that you took the bother to report back.
(Consider clicking the "thanks" button at the bottom right of any posts that helped you, please).
 
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