Question about Televison & Video

2 Answers

Panasonic TH37PA50E 3yrs old In AV1 mode, disconnected from all video sources, scintillating blue horizontal bands slowly scrolling up the screen. Turns red when set to component video. When connected to antenna produces clear undistorted picture, but with horizontal scrolling bands discernable in background of dark scenes (not disturbing picture itself) but making it irritating to watch. Have disconnected the set from all other video devices and replaced it with another set which works fine. Thus source of picture problem is definitely internal to the TV set. Onset of the problem was sudden, (watching it at the time) and has been ever present since start.

Posted by on

  • 1 more comment 
  • harry99 Apr 29, 2008

    Thanks very much for that.

    All the video inputs go via the video processing function on a Yamaha AV system first. The set is 5 metres from the AV amp so a long component cable is used to connect them just to the component sockets.

    Is there a video amplifier board that can be replaced?

  • harry99 Apr 29, 2008

    Yes. It didn't help.

  • harry99 Apr 30, 2008

    Bestdarngood,
    Sorry not to responded.

    Many thanks for your advice. I am inclined to think you are right about this. I have obtained a service manual, and although I am familiar with using a signal generator and scope; it is many years since I undertook this kind of work. Happy to pull a computer apart and fit boards etc but I think this is over my comfort limit.

    The set is obsolete in terms of the way the UK is now rapidly moving, and the cost of a repair is high in relation to aquiring a new one. I didn't pay anything like the retail price on the high street for it in the first place, so I think it is time to replace it.

×

2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 3,037 Answers

Alright, this problem is called hum or more correctly 60Hz-120Hz Hum it is caused by a partially open or an open filter capacitor in the power supply of the TV. The filter capacitor's job is to filter out the 60Hz - 120Hz ripple voltage that is present on the power supply's output.

When this cap fails the hum bleeds into the various stages and causes the lines that you are seeing on the video screen. To troubleshoot this problem you will need a schematic diagram (to locate the power supply test points and to get pictures of the correct waveforms that should be present), a signal generator (to generate a reference signal), and an Oscilloscope (to view the waveforms at the test points). What you will be looking at are the outputs of the power supply checking to see the level of the ripple voltage present on the outputs.

If you do not have the tools needed or any knowledge of working on electronics, then I would suggest getting a qualified repairman to fix this problem and the cheapest way is to take it in and not have them come out.

Let me know if you have any further questions on this problem

thanks

Posted on Apr 29, 2008

  • 1 more comment 
  • Benjamin Patri
    Benjamin Patri Apr 29, 2008

    its not the amplifier

  • Benjamin Patri
    Benjamin Patri Apr 29, 2008

    have you taken a look at my advice at all?

  • Benjamin Patri
    Benjamin Patri Apr 30, 2008

    no problem, good luck with the replacing

×

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 2,296 Answers

It looks like the TV might have retrace lines that are cause by a defective video amplifier IC, couple of fuse resistors burnt.
You might be able to make an adjustment to the blue screen voltage by reducing it slightly to get rid of the lines.
The devices that you connect to the TV have a different output and the TV is very sensitive to the higher video outputs from the DVD or any other device that you connect using the AV inputs.
Let me know if you need more assistance.

Posted on Apr 29, 2008

  • 1 more comment 
  • Jaime Hernandez Apr 29, 2008

    Plasmas are a bit more difficult to repair due to complexity of their boards.

    At this point there might be the need for some adjustments to the voltages powering up all the assemblies on your TV.

    It requires the use of a good multimeter, a 200Mhz oscilloscope and the know how.

  • Jaime Hernandez Apr 29, 2008

    Have you tryied Switch on P-NR in Picture menu to reduce picture noise?

  • Jaime Hernandez Apr 29, 2008

    Try connecting the other video sources directly to the TV with shorter cables, just to eliminate some noise that could be picked up by the long cables.

×

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Horizontal Band of Thin Red and Blue Lines on Screen


Sound like your Y-Sustain board has one foot in the grave. The Y upper buffer and Y lower buffer boards go when the Y Sus Goes too...

Mar 22, 2014 | Panasonic TCP46C2 46 in Plasma TV

2 Answers

Samsung ln52a650a1fxza LCD has horizontal band of dark lines across screen


check connections on top of screen this is becoming a stockfault on samsung tvs

Dec 01, 2012 | Televison & Video

1 Answer

Is a panasonic viera tx-174 HD READY ITS OLD FLAT SCREEN


Can you select the source on your remote control, and does it give you the options AV1, AV2 , Scart, and the most important one, HDMI, if it has the option HDMI it possibly is HD Ready.

Apr 09, 2012 | Panasonic Televison & Video

1 Answer

5 year old panasonic viera LCD works great until tonight, screen turned into vertical and horizontal rainbows, can see vague picture behind all the lines like looking through thin black horizontal venetian...


make sure your speaker to your sheron sound isnt to close to it .also if dvd player is the source then move away from tv will demagnatize the tv theres a magnet in them

Jul 05, 2011 | Panasonic Viera TH-42PZ80U Plasma TV

1 Answer

I have a 2010 model Panasonic Vierra Plasma, 55" screen, and we recently noticed a narrow, horizontal, slightly dark shaded band that is continuously scrolling from the bottom to the top of the...


You might try isolating the source by disconnecting the cable (or satellite receiver) and try it with another input device such as a DVR, VCR or other video source. This banding was not uncommon on analog sets but very seldom seen on our current digital sets. But, it could be embedded 'noise' in the signal coming in from outside the set.

Feb 16, 2011 | Panasonic TC-P54V10 54 in. HDTV Plasma TV

1 Answer

The blue adjustment is not working - a blue band has formed at the bottom of the tv screen


Press the menu button, if the blue is still present the tv will need repair. If there is no blue line try a second source, either a dvd player or a game system. If the issue is only with the original source it is the original source that will need to be replaced.

May 06, 2010 | Panasonic PT-47WX53 47" Rear Projection...

1 Answer

Ag-dvc20p blue stripes in play back mode


Blue stripes in playback is an indication that you need to clean the heads. A Panasonic cleaning tape should work fine.

Jan 22, 2010 | Panasonic AG-DVC200 DV Digital Camcorder

1 Answer

Blue screen


At least a couple of possibilities, check the yellow video cable that runs from the VCR to the TV, is it plugged into the side of the combo unit that says vcr?

Is your TV on the right source? You could have plugged the audio into say AV2 and the video into AV1, causing a mismatch. Make sure the yellow, red, and white are all plugged into one input section on the TV (AV1, AV2, Video 1, Video 2, etc).

Dec 09, 2008 | Philips MRV700VR DVD Recorder/VCR

1 Answer

Camcoder (Panasonic PV-GS15) does not play back recording


Sorry to say- but it is trashed.. It would cost more to fix it than it would be to buy a new one.

May 06, 2017 | Panasonic NV-GS10 Mini DV Digital...

1 Answer

Banding on LCD TV


you need a new motherboard

Dec 09, 2007 | Televison & Video

Not finding what you are looking for?
Televison & Video Logo

Related Topics:

91 people viewed this question

Ask a Question

Usually answered in minutes!

Top Televison & Video Experts

The Knight
The Knight

Level 3 Expert

72670 Answers

Electro Med Services...
Electro Med Services...

Level 3 Expert

6694 Answers

yadayada
yadayada

Level 3 Expert

70387 Answers

Are you a Televison and Video Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...