Panasonic CinemaVision HDTV Problem

[jonboy73]

My Panasonic CinemaVision HDTV is making this sound like humming and the picture has these bright white horizontal lines that appears at the same time as the humming. Text in the picture will have this white bleeding.

I hope I described the problem clearly? Can't figure out how to describe the problem exactly. :sightv: Does anyone have an idea as to the problem?

Thanks!

[57U]

Sometimes people get this if they have their contrast set too high, it stresses the power supply and causes the bleeding you mention. Perhaps a proper setup of the TV will help. See the following post on that topic.

http://www.hdtvoice.com/voice/showthread.php?t=1440

You could experiment simply by choosing a different picture mode and lowering the contrast to see if it goes away. If it goes away, then start calibrating.

You can also try unplugging the TV overnight to see if a reset solves the issue.

[jonboy73]

Well, I took your advice and read the other post. Did all the settings and did get a better looking picture. The bad news is that I still have the problem.

I took a short video clip of the TV in action. Disregard the horizontal motion lines moving upwards which the video camera picks up but notice the horizontal lines at the top of the picture. Notice near the end of the video that the horizontal lines go away and so does the humming.

Video: http://pages.suddenlink.net/jonrans/files/tv.avi

Any ideas???

[57U]

Thanks for the video. The horizontal line went away when the picture changed from the bridge to the guy. What happened there - was it a different programme a different shot a different input - what?

[jonboy73]

Thanks for the video. The horizontal line went away when the picture changed from the bridge to the guy. What happened there - was it a different programme a different shot a different input - what?

No, not a different program. It just seems to come and go just like it did in the video when the picture changed. I'm not sure what is going on with this thing but it is very annoying. Oh, I failed to mention that it does not do this on all the channels only a few. I have noticed that the problem has started on some other channels lately that were not originally in the group.

Any ideas? :sherlok:

[Knicks4973]

If you are using an HDMI connection, try using a Component cable instead. My old Toshiba had a similar problem where I would get scan lines and a buzzing noise (not as loud as yours) when using HDMI, but never got it using component. Making the change will narrow down if the issue is with your HDMI input, the HDMI cable, or if it's the STB.

It's worth a shot...

[57U]

If it's specific to some channels, then there could be something wrong with those channels, or perhaps the device connected to the TV? Do you have a STB (set top box) and what is the make/model? Who is your service provider?

In addition to the HDMI suggestion above, here are some more things to check (link at the bottom of the HDMI post:

http://www.hdtvoice.com/voice/showthread.php?t=33977 HDMI Issues

[jonboy73]

Thanks guys for all your advice! To answer your questions the TV is connected directly to the coaxial cable from the wall. My other TV's are not big screens or HDTV so I figure this to be the reason for not getting this problem with them. I figure that my big screen TV is more susceptible to signal quality verses the others??? Service provider is Suddenlink.

[jonboy73]

I hope you guys have not given up on me. Your advice so far has been great but now I'm stuck and don't know what else to do. Waiting for replies. :whistle:

[Ratman]

My thoughts:
1) check or replace the coax cable from the wall to the TV.
2) what other devices/components are on the same electrical circuit (dimmers, fluorescent lamp/bulbs, baby monitors, sump pump, fridge, etc.)? Maybe interference?

[jonboy73]

Ok, checked all that too. I moved the TV into another room last night and got the same thing. However, I stayed up late last night (2:00 AM) and noticed that those channels with the problem was working just fine. This morning it was back again? :sobbing: I just can't figure this out!

[57U]

Perhaps keep a log of the times it happens and as indicated by Ratman in post 10, see if that coincides with anything coming on, etc in the home, or perhaps outside the home.

If the problem is with the source, do you have any neighbours with the same service that have similar issues?

If the bar were moving, I'd say you have a ground loop, but you say it's at the top. Perhaps you can check for a ground loop problem anyway by checking for proper grounding of the incoming cable. Also a good surge protector or UPS may help if you feed the coax through it (just as a test). This "band aid" may help, but it's usually better to track down the real cause.

[Ratman]

Another thought...
Do you live near a business that has neon lights (or similar signage)? That can create "RF noise" also.

[jonboy73]

Another thought...
Do you live near a business that has neon lights (or similar signage)? That can create "RF noise" also.

No, I'm way out in the country.

I decided to haul the TV to my neighbor's house today to eliminate everything in my house. Result: It still has the problem! Now I have my finger pointing at the TV unit as the problem. Does anyone have any idea what component within the TV itself would cause this?

The Model# is PT-47WX49E if anyone has a service manual and can tell me what to check. I have a Multimeter and Oscilloscope.

[jonboy73]

I guess everyone finally gave up? :mecry:

[Knicks4973]

Why not call Suddenlink and ask them to send out a technician? The problem may be resolved if they hook up the cable from a STB. Right now your getting HD, or supposedly HD from the coaxial cable. If they hook the TV up to the STB using component or HDMI, the issue could be solved. That's a better option then going into the TV and messing around, unless you yourself are a trained technician.

Also, you mentioned bringing the TV to a friends house. How did you hook up the TV there? Was it coaxial cable or was it with another cable, like component or HDMI? If it's coaxial, then maybe the issue is not with the TV but with the cable in the area itself.

If you get a STB, you might see a difference.

[Ratman]

Although using an STB may eliminate the observed "problem", the TV should not produce those issues using the internal tuner. Since the problem can be reproduced at two different locations, I'd lean towards an internal tuner problem with TV.

Having a cable tech check things out wouldn't hurt though IMO.

[jonboy73]

Well, my neighbor has a TV similar to mine and he is not having the problem with his. We both are connected directly via coaxial cable. Suddenlink says there is nothing wrong on their end so I'm trying to figure it out on my own.

I do have a background in electronics as an electronics engineer but I have never worked on TV's and I don't have a schematic or service manual to work with. I have an Oscilloscope and DMM to test the circuits and components but at this point I'm not sure what is what without the schematics.

[jonboy73]

...Since the problem can be reproduced at two different locations, I'd lean towards an internal tuner problem with TV.

Can you tell me more about the tuner? Do you know how I can check for problems with it? I noticed the problem getting into other channels now that was working fine just days ago. I'm going to try some cleaning today to see if that might help things out a bit. Trying anything and everything at this point! :headb:

[Ratman]

1) no... I don't own this TV
2) no... If you only have problems using the tuner and nothing else presents the 'problem' (DVD's, gaming systems, etc.), then it may be the tuner. Or... another circuit/component that works in conjuction with the tuner.

Best suggestions?
1) purchase a service manual and keep trudging along.
2) have your TV serviced by an authorized Panasonic tech
3) try using an external tuner (as suggested above in post#16)
4) start looking for a new TV.

Sorry I can't be more helpful.