Last night I noticed several wide purple (but transparent) slowly moving up from the bottom of my display in my FP (DLP) system. I don't know where the bars have come.

I last week replaced my satellite box with a HD box, but the system seemed fine after that change.

I just a couple of days ago replaced my old powerstrip with a new energy-efficient one. Since last night was the first time I had used my system since that change, I naturally thought the bars were due to the new powerstrip. But when I replaced it with the old powerstrip, the bars were still there.

I don't see the bars when just my FP is on. But as soon as I turn on my receiver and get a signal from my DVD player or satellite dish, the bars appear.

I suppose I bumped or moved some cable when moving my entertainment center in and out to replace the powerstrip, but I have no idea which one or what could cause this.

I really hope one of you has a better idea of the cause and solution than I do and can give me some advice!

Sounds like you have a ground loop.

If you unplug the cable feed from the cable box and it goes away then that is definitely the cause.

Thanks. I wondered about the same thing. But I did not hear any hum in my system. And why would a ground loop suddenly have started? My system has worked fine for years before this started and even replacing my old powerstrip does not solve this problem.

I will check my cable feed when I get home tonight. But if that is the problem, how do I solve it? I can't leave my cable box without any feed forever.

You won't necessarily hear a hum with a ground loop.

There are quite a few things that you need to try such as checking the ground connection for where the cable comes in, making sure all of the A/V equipment is on the same outlet, etc.

I suck at electrical things. My satellite cable comes in from the wall, goes to my powerstrip, then goes out from my powerstrip to my satellite box. Where and how do I check my cable ground?

Here's a recent post/thread (http://www.avsforum.com/avs-vb/showpost.php?p=13538927&postcount=15) mentioning low-cost ground loop fixes. While ~$12 might do the job, if it's a cable system fault they might fix it for nothing--and do a better job (no signal interruption/attenuation, assuming you eventually get an in-the-know tech). -- John

Thanks for the help. I think I have gotten rid of the ground loop.