Ground Loop / Hum - Page 2 - Videokarma.org TV - Video

Dave A · #16 11-12-2008, 08:14 PM

Is the power supply on-board or a wall-wart? Either way, it could be faulty and leaking AC to the modulator. What happens if you move the modulator to another set?

ihmeyers · #17 11-12-2008, 08:59 PM

On board power supply. Haven't tried the modulator on another set but did try a different modulator on this one. It was worse.

I think it's got to have something to do with overloading the set because it screws ups some of the colors as well. Not very noticeable on programming but the DVD welcome screen is purple at the top of the screen when it should be all dark blue (I tried the DVD player on a new set). No amount of AGC adjustment will fix it. Bob suggestion about adding caps helped somewhat but didn't fix it. I'd switch DVD players but the one I use doesn't have macrovision so I don't have any problems with protected DVDs.

*zenithfan1* · #18 11-12-2008, 09:12 PM

Sounds like a purity issue, it shouldn't be purple at the top no matter what, unless there is something purple there of course. Is there a stray magnetic field around? Maybe the power supply on the DVD player?

ihmeyers · #19 11-12-2008, 11:19 PM

Hmm. The power cord for the DVD player runs right next to the back plastic casing for the picture tube. If I adjust the fine tuning on the set the purple will become, red, green, orange. When finetuning and AGC is optimally adjusted the top of the screen is purple. Maybe I need to re-route. I've also observed that there's an rf choke on the DVD power cord. I think I'll try removing that as well....

Nope. That didn't help. Moved away both the power cord from the modulator and the DVD player. Still have that purple along the top. Also a dark shadow along the right hand side of the screen. Almost like a one sided cataract. It's not there on program content and isn't a problem on broadcast channels. Also if I adjust the fine tuning on DVD program content I can make those rainbow colors appear at the top of the screen.

freakaftr8 · #20 11-13-2008, 11:25 AM

Dont mean to sound dumb, but are you sure your modulator and your tv are set top the same channel. Just for s&g's, try tuning it to channel 3 and fine tune your tv in on the oppisite channel. It's always possible that the modulator could me misprinted...

ihmeyers · #21 11-13-2008, 05:32 PM

Quote:

Originally Posted by freakaftr8

Dont mean to sound dumb, but are you sure your modulator and your tv are set top the same channel. Just for s&g's, try tuning it to channel 3 and fine tune your tv in on the oppisite channel. It's always possible that the modulator could me misprinted...

Tried that too. The modulator appears to be labelled correctly. Does it sound like an overload on the set from the modulator? The Phillips modulator I got earlier this week was actually worse. Problem exists even if I go through a wireless modulator like a rabbit. Maybe the output is too high on the DVD player, but its really the only option I have since it doesn't have Macrovision and nearly all others do. Really at my wits end with this...

freakaftr8 · #22 11-13-2008, 08:38 PM

Wow! Wild! Dude try another DVD player... Do you have a video game console you can run through the rf modulator, also disconnect one lead from your tv input, see if the symptom changes.. Im assuming that the blue background is normal standby for the DVD player orr not? The purple blob looks like a putity glitch. One more thing, try tweaking the horiz hold back and fourth very slightly..

ihmeyers · #23 11-14-2008, 09:24 AM

Quote:

Originally Posted by freakaftr8

Wow! Wild! Dude try another DVD player....

The firmware on this DVD player has been changed to remove Macrovision. With an off the shelf SONY DVD player I was getting that copy protection pulsing on about half my DVDs. I don't think there are any other DVD players without Macrovision and I preferred not to buy another one anyway. Maybe I'll have to...