other electrical appliances interfering w compute rmonitor - how to troubleshoot

So, I have an LCD tv hooked up to a Scientific Atlanta cable box on one outlet. On the same circuit (but different outlet), I have a CRT computer monitor plugged into an APC Backoffice UPS (into which the computer is also pluged in). On a different circuit in the kitchen are items such as the microwave and toaster oven and the fridge.

So, if I run the microwave, the picture on my computer CRT is quite shaky and I get quite a bit of audio hum in the sound from the cable box/lcd tv. If the toaster over is running, the crt is less shaky, and I don't notice any audio hum. If the fridge is running, there is a tad of shakiness (could be mistaken for poor refresh rate on the crt). It's unclear if the water heater is causing any problems, and the window AC does not seem to be causing noticable problems, either (tho, it's upstairs on a different circuit). However, I have actually seen the shakeys seem to get better sometimes when the toaster over is on and then the window ac comes on. The washing machine and dryer are definitely causing some monitor shakeys.

So, any thoughts on what is going on and what I can do to eliminate the interference problems? I'm guessing not a short to ground since no circuit breakers are blowing. Is there some sort of grounding loop? Some sort of inductance going on? Something I can test for with a multimeter and then go to the apartment people and say "look, this needs to be fixed, here's the evidence"?

Thanks in advance!

ps this was posted in a different group and the folk there suggested this group.

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David William Botsch
dwb7@cornell.edu
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Reply to
Dave Botsch
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Sounds like magnetic interference. Try moving the CRT at least 10 feet away from every other unit and see what happens. If that eliminates the problem, then one by one see just how close the units can be without causing problems -- magnetic fields fall off very quickly with distance; much faster than distance^2.

I have a small floor fan that gives my CRT the shakes at nearly four feet, but presents no problem at about six.

Isaac

Reply to
isw

It is at least 10 feet away.

Funny th>

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********************************
David William Botsch
dwb7@cornell.edu
********************************
Reply to
Dave Botsch

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