Lines going up my TV. GRRRRRR.

December 20, 2005 1:27 AM

I've just moved into a new apartment and plugged in my entertainment center. My television, a 32 inch CRT Samsung which has always before had an excellent picture, now has these bars moving slowly upwards over the picture.

Lemmie describe my set up a little better. All on this little cart I have the TV, an RCA 5 channel surround audio receiver, a dvd player, a VCR, a PS2, the front 3 speakers of the surround sound system. Off to the side I have a sort of media center computer which plays my movies on the tv over s-video.
Everything plugs into this little s-video switch, and goes into the back of the TV from there.

My first thought is that I am having an issue with the quality of the electrical power, because that is really the only thing I can think of that could be different from my set up back at my old house. Perhaps the outlets here can't handle this many gadgets?

The power thing is sort of a guess. What do you think? I'm really wondering what the most likely cause is of this, and if there's anything I can do about it.

posted by shanevsevil to Technology (12 answers total)

Sounds like the TV is poorly tuned to the signal. I don't see why that would affect the input from your PS2/VCR/DVD, but your TV reception willl vary from street to street.

Have you tried hand-tuning the set? Check the manual and nudge it up or down a couple of notches.
posted by NinjaPirate at 1:35 AM on December 20, 2005

Do the bars persist if you move the tv to a different location? If not, it could be interference from a powerful magnetic field (like a transformer on the other side of the wall, etc)

Other possible thought: Are you feeding your gear from different circuits? Could be getting line noise from ground loops, etc.
posted by drewbage1847 at 1:38 AM on December 20, 2005

Could the TV have been damaged during transporting it to and from apartments?
posted by slater at 2:38 AM on December 20, 2005

Interesting. I have the same problem, but only with a PC hooked up to the TV via S-video through the same type of box you mention. It's happened in two different homes, and it also happens sporadically. Sometimes the bars are really prominent, sometimes faint, and sometimes not there at all. Can you plug one on your components directly into the TV and see if you still have the problem? That would confirm/eliminate the switch box as the problem.
posted by Otis at 5:06 AM on December 20, 2005

On the principle of starting with the cheapest fixes first, I've seen that with a bad SCART cable.
posted by Leon at 5:34 AM on December 20, 2005

Slowly-upward-moving dark bars are indicative of ground loops. Make sure all of the devices are well grounded with their three-pronged cords, and verify that all devices are plugged into the same outlet, via a power strip or similar.

If it persists after doing this, you probably have poorly-sheilded video cables, one of which is probably in close proximity to a transformer or AC cable.
posted by tomierna at 5:48 AM on December 20, 2005

(tomierna's advice is better than mine - I bet that when I replaced my "bad" cable, I used one with better shielding)
posted by Leon at 6:11 AM on December 20, 2005

Best answer: This is 60-cycle video hum from ground loops. Most likely from the s-video switch unless it's a really quality model. Disconnect everything. Turn the tv on and connect once source. Disconnect and try another source. See if any of these components cause the hum by themselves. If not, add components one at a time to see which combination is causing the loop. When you find it, to make sure that is the problem, put a ground lift on it (3 to 2 prong adapter). If the hum goes away, that is your ground loop. Some people would say don't lift the ground, it's dangerous. Which it might be, under very rare circumstances, like a short or water poured over your system. The ground is there for safety. The "professional" solution is to purchase an isolator. But sometimes, you can get away with lifting it. For a thorough discussion of ground loops, both video and audio, check here.
posted by Roger Dodger at 6:57 AM on December 20, 2005

Response by poster: Hmmm Right now nothing is grounded. There weren't enough grounded outlets around and I had to go out and buy a little thing with that turns an ungrounded outlet into 3 ungrounded outlets. Nearly everything is plugged into a surge protector that is plugged into that thing. My television, however does not have a ground plug and therefore I plugged it straight to the wall.

So basically nothing is grounded.
Should I start by trying to ground some stuff?
posted by shanevsevil at 10:36 AM on December 20, 2005

Response by poster: I've been reading up on your link, Roger, and I think my best bet is to go out and get a ground loop isolator for between my TV and my devices. I'm going by radio shack today.
posted by shanevsevil at 1:58 PM on December 20, 2005

You have some loops going on. Try plugging things in one at a time. Maybe you can ground lift something at the surge protector. Or maybe it's the common ground in the surge protector that's looping. You'll just have to figure out where the loop is, just keep trying different combinations hooking up your stuff. Actually, try plugging your TV into the same surge protector as all of your other stuff. That might take care of it too. And check out the link I gave you. It's got tons of info.
posted by Roger Dodger at 2:02 PM on December 20, 2005

Jinx!
posted by Roger Dodger at 2:03 PM on December 20, 2005