AVS Forum banner
Status
Not open for further replies.
1 - 20 of 22 Posts

·
Registered
Joined
·
37 Posts
Discussion Starter · #1 ·
I just got this display from VisualApex. The S-Video input has a lot of what looks like noise. This appears as rolling light and dark areas in the picture. The component inputs do not have this problem. Turning the brightness way down will make this less noticeable but you can still see it. I've tried two different DVD players and different cables, no difference.


Do I have a defective S-Video input?
 

·
Registered
Joined
·
3,301 Posts
Quote:
Originally posted by zxrocksteve
This appears as rolling light and dark areas in the picture.
This description doesn't paint a very good picture for me. Would you say that looks like horizontal lines (or bands) that are scrolling up or down the screen (vertically)?


If so, that sounds like some kind of a ground loop issue.
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #5 ·
Quote:
Originally posted by Brucer
This description doesn't paint a very good picture for me. Would you say that looks like horizontal lines (or bands) that are scrolling up or down the screen (vertically)?


If so, that sounds like some kind of a ground loop issue.
Yes it looks like horizontal lines (or bands) that are scrolling up the screen.


I also tried composite video, it looks worse. Component Video looks great.


Here's an attached picture of this. The display is currently showing DVD output of a black screen from DVE. The brightness and contrast are at factory levels for standard. This is a little too high for normal viewing but it shows the problem better. It's on dark screens where this is most noticeable. Though you can still see it on a brighter screen, even with the brightness level turned down.


The display is currently plugged into a Monster HTS2000 power strip. I had it plugged directly into wall AC for a while. This made no difference.


I also disconnected the component video cables so only AC and S-Video go to the display. No difference.


I sent an email to Visual Apex. A Paul called me back, but I was out. I'll talk with him tomorrow.
 

·
Registered
Joined
·
3,301 Posts
From what I can see in that picture, I now think less likely ground loop (at least based on what others have described as the symptom). If possible, can you try a different S-video cable.


Otherwise, read this report about the S-video (slot card) behavior during an ISF calibration in the UK. I'm worried it sounds similar:

http://www.avforums.com/forums/showt...threadid=95362
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #7 ·
Quote:
Originally posted by Brucer
From what I can see in that picture, I now think less likely ground loop (at least based on what others have described as the symptom). If possible, can you try a different S-video cable.


Otherwise, read this report about the S-video (slot card) behavior during an ISF calibration in the UK. I'm worried it sounds similar:

Yes I tried a different cable, no help. Composite looks worse. Again, Component looks great.


From the "ISF calibration in the UK" post,
Quote:
inability to hold black level independant of picture level
and
Quote:
when fed the pluge pattern generated by DVD32R the darker bar only had the top inch or so visible
I see this also with the test patterns on the DVE DVD when using S-Video.

Quote:
I should mention that this was the small s-video in board not a full width board.
I'm using the full size board I guess. It's the standard board from Panasonic.
 

·
Registered
Joined
·
1,224 Posts
Looks for all the world like ground loop at first glance.


1.) Is cable or sat dish hooked up ? Even if that input is not used, differentials between coax connections can cause this symptom.


2.) Bypass the "surge protector" and plug all devices into the same AC outlet, even if just for a test.


For #1, an RF/cable ground isolator like those from Jensen Transformers may be needed. For #2, some AC isolation or inter device grounding with heavy guage wire may help.


There is probably not a problem with the Plasma although Paul G. at VA will help you all the way from his end if needed.


T. Wiz
 

·
Registered
Joined
·
3,301 Posts
Thanks T.Wiz


Boy, I hope so. Only reason I became less convinced was that I thought generally the scrolling lines symptom looked more like colored (static) lines.


Steve- T.Wiz has indepth (hands-on) knowledge on the technical side of the Industrial Pannies.
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #11 ·
Quote:
Originally posted by Brucer
Ugh!


Well it may be a problem, then. I don't think I can help 'ya beyond this.


This may or maynot be related, but since you mentioned using DVE, did you see this post (& follow up link) about the pluge pattern & passing blacker than black?

Yeah I saw that. My Denon DVD passes the "blacker than black" on the component output, but does not appear to on the s-video. My Sony DVD does not. The Sony does not have component video outs.


Also what exactly is the "Black Level" setting on the Denon for? When on I can see it boost the level of the black, but why would I want to do this? I have this setting turned off.
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #12 ·
Quote:
Originally posted by Techniwizard
Looks for all the world like ground loop at first glance.


1.) Is cable or sat dish hooked up ? Even if that input is not used, differentials between coax connections can cause this symptom.


2.) Bypass the "surge protector" and plug all devices into the same AC outlet, even if just for a test.


For #1, an RF/cable ground isolator like those from Jensen Transformers may be needed. For #2, some AC isolation or inter device grounding with heavy guage wire may help.


There is probably not a problem with the Plasma although Paul G. at VA will help you all the way from his end if needed.


T. Wiz
1.) For testing I only have the DVD player hooked up and nothing else.


2.) I'll try this.
 

·
Registered
Joined
·
333 Posts
Try to borrow a DVD player from a friend.


Also plug you DVD player into another TV...


Nice thing is that Panasonic may be able to ship a new blade and that could fix the problem. No in home service on the commerical plasmas.
 

·
Registered
Joined
·
3,301 Posts
Steve-


We have a local service center here in the Dallas area if it turns out to be a problem, this same shop services both Consumer & Industrial units:


The Electronic Shop

2820 Walnut Hill Lane

Dallas, Texas

214-350-4003
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #15 ·
Quote:
Originally posted by Brucer
Steve-


We have a local service center here in the Dallas area if it turns out to be a problem, this same shop services both Consumer & Industrial units:


The Electronic Shop

2820 Walnut Hill Lane

Dallas, Texas

214-350-4003
So I was able to work with Paul at Visual Apex and a Alex at Panasonic. By moving some cables around the noise in the S-Video and Composite inputs seems a bit better. I still feel there is more "noise" in the picture on these inputs than there should be. Component input looks great. I've tried different source devices and cables and I can see no difference. I'm using quality MonsterCable S-Video cables. I’m wondering if this problem is power related. Are these displays known to be sensitive to power line noise? I noticed the other night while I was looking at it the noise changed slightly when the refrigerator kicked on. Would a power filter like the Monster HTS 5100 help?


Brucer, are you affiliated with The Electronic Shop? If I brought the display there can you guys run some tests on the inputs so I can see if the problem is in the display or something external? Would the cost of this testing be covered under the Panasonic warranty?
 

·
Registered
Joined
·
19 Posts
My new TH-37PWD6UY arrived today, and I'm having the same problem - rolling large horizontal bands of dark and light. Happens with composite and svid connections, with all cables I have, and no matter how I try plugging in the power. Panasonic tech support said they think it needs to be serviced.
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #17 ·
After studying this some more I'm thinking this sure sounds like a ground loop issue. I'm not sure how to fix this if it is.

Will a S-Video Isolator Model VS-1SS from Jensen Transformers fix this?
 

·
Registered
Joined
·
3,301 Posts
Quote:
Originally posted by zxrocksteve


Brucer, are you affiliated with The Electronic Shop? If I brought the display there can you guys run some tests on the inputs so I can see if the problem is in the display or something external? Would the cost of this testing be covered under the Panasonic warranty?
Absolutely not affiliated.
 

·
Registered
Joined
·
19 Posts
Quote:
Originally posted by WagGag
My new TH-37PWD6UY arrived today, and I'm having the same problem - rolling large horizontal bands of dark and light. Happens with composite and svid connections, with all cables I have, and no matter how I try plugging in the power. Panasonic tech support said they think it needs to be serviced.


Hmmm, I ran an extension cord to try plugging the power into a different part of the house, and that pretty much solved it. I.e. a blank black signal no longer shows the horizontal bands. Although it's still not perfect - you still see some liney graininess, especially toward one side of the screen.

So apparently I have some kind of electrical problem. I don't know whether the remaining graininess is a) still a house electrical problem but to a lesser extent, b) a problem with my unit, or c) "normal". Any advice would be appreciated.
 
1 - 20 of 22 Posts
Status
Not open for further replies.
Top