TV shows stripes/lines at the top of the screen

Hello! I have Panasonic TV about 1 year old. It was working great til a few weeks ago, now it shows stripes/lines at the top of the screen that used to get better after tv was getting warm. Now I got more stripes/lines at the top of the screen and they don't dissapear even when tv gets warm. I removed the tv rear cover and found only 2 knobs for Focus and Screen and they won't solve the problem. I tried to adjust Var Resistor and again nothing. What can I do? What should I check for? Please help.

Thanks,

Almazick

Thanks for your response but it's not what I'm looking for. I'm looking for help and to point me to the right direction. If I wanted to give it to service I would done it a long time ago but that's no fun at all. That's the idea to learn it and do it yourself. Also If I had no idea what I was doing I wouldn't even touch it but I've done in the past couple of projects creating PCB and making IC to work. It's all about fun and enjoying what you are doing. This is diy electronics repair forum and people expect to get help to solve the problem not to create another one just like you advised it and please next time stay on the subject and don't create another one.

It is a nice idea that you would like to fix it yourself, but I have to say that the advice that you were given by Tech Data, in this case, was valid for your own safety, if nothing else. Modern TV sets are DANGEROUS items - probably more so than their predecessors. They all utilise switch mode power supplies, and if you do not understand these, or work with them on a regular basis, and have a proper transformer-isolated safety supply to run them from, then they can be lethal - and I mean that by the most death-causing literal definition that you can find.

Creating PCBs, and making ICs work do not, unfortunately, qualify you to be poking around safely in the back of a TV. Even twiddling the screen pot, without knowing what it does, or how to readjust it correctly so that you don't have a useless CRT on your hands in a couple of months, to add further to your woes, indicates that you should not be attempting this.

Whilst this is a DIY repair group, for some types of repair, a degree of expertise is still required, and in our opinion, you simply don't have the necessary expertise to be attempting a repair such as this. Those of us who do, would be irresponsible to advise you to try, for your own safety. The advice you were given was good, and I think the same as most of us would have given - take it to a reputable repair shop. If you really don't want to spend the money on it, and it really is just a year old, then pick up the phone and bleat long and hard to Panasonic's customer liason - you might just get a result, and live long enough to enjoy it ...

Also, if you wouldn't mind, please don't top-post. It makes threads difficult to follow once they get above a couple long.

Arfa

Wow, thanks for putting me in my place. Did you realize that you posted twice and, by omission, indicate that you think Panasonic made only one television, ever, and you own it? If you expect someone to lead you to a magic fix, you might want to post a model number or, at the very least, a color.

The problem is likely a bad capacitor in the vertical deflection output.

But I agree - get it fixed by a professional and DON'T touch any of the internal adjustments! This is a circuit failure.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

If you'd provided a model number and resisted the temptation to indulge in dangerous buffoonery, then maybe the *group* (this is *not* a forum!) would have considered you had enough credibility to undertake a repair. However, by your actions you have demonstrated that the only successful undertaking will be your subsequent funeral.

You clearly do not understand televisions or their circuits and adjustments, and I'm certain few people would recommend you learn the craft with a good, newish TV when they know full well you may injure/kill yourself or wreck the TV. Seriously- anyone who thinks the 'focus' control will cure lines at the top of the screen has no business inside a TV set- even my 13 year old daughter knows what 'focus' means ;-)

Furthermore, a basic rule of repair is that adjusting things when a fault arises is a no-no. Apart from the simple fact that it rarely helps to effect a good repair, it will at best mask the fault, and at worst make a simple repair into a realignment job which increases the total repair cost. Worse still you randomly adjusted settings you didn't understand- what did you hope to achieve? Would you randomly adjust things on your car's carburettor if the tail light developed a fault?

If you want to learn TV repair, I recommend you get a good book and understand how they work before you go inside and practice, you and the TV will live longer.

The answer to your question is electrolytic capacitors in the vertical deflection circuit as Sam stated- about 99% certainty. It's not an expensive job and straightforward enough for a half decent tech, so I recommend you pay to get it done.

As for wanting to fix it yourself as part of a learning process, learning what exactly? You had to come here to ask where the fault was, so the hard part has been answered for you. The remainder of the job is soldering in replacements, far better you practice soldering on a scrap PCB than a year old TV.

Good luck with your TV, and stay alive!

Dave

Thanks a lot for the answer. Sorry for not posting the model because I did not think it was very important just because it is a general problem. I spent all night reading tv problems and found similar problem with the same answer. I was wondering where can I get Service Manual for Panasonic CT-24SL14J or just a schematic to find bad capacitor in the vertical deflection? I checked IC yesterday but I couldn't find a bad capacitor by an eye. Regarding safety I do understand it is very dangerous to put your fingers inside of the tv because of the High Voltage unless your discharge capacitors or follow safety code. I learned my lesson a long time ago. I do know what I'm doing and it is not the first time. I also understand that I don't have enough experience but again it is all about learning.

On Sun, 11 Jun 2006 14:49:40 -0600, "-Almazick-" put finger to keyboard and composed:

Look for an IC on a heatsink, possibly an LAxxxx type. Then download its datasheet and study the application circuit therein. You will see several electrolytic capacitors. You may as well change all of them - they are cheap enough.

BTW, in Australia you would be entitled to a free warranty repair on the grounds that your one year old (?) TV is not of merchantable quality. This is despite the fact that the manufacturer's voluntary warranty is only 1 year.

- Franc Zabkar

--
Please remove one 'i' from my address when replying by email.

By eye? No good in this case. Testing with an ESR meter or substitution is the way to do it. If in doubt, just change all the electrolytic capacitors in the vertical deflection area, they aren't expensive parts and it could prevent further trouble.

Dave

Great I found everything already. Instead of LA4845 it is using AN15525 IC. In datasheet it shows 3 caps in example schematic. I'll try to replace on tuesday some of my caps in my tv. Really bad that I don't have ESR meter should make my job a lot easier :) again thanks a lot.

Troubleshoot the set for defective components in the vertical deflection area. It is impossible to guess to the exact components. There are many involved. You will require at the very least, a DVM, ESR meter, and the service manuals for your set. If the problem gets complicated, you will need a scope. Also, it is an asset to have the proper training in electronics, and in TV servicing.

Your best solution is to bring the set to a service centre and have them service it for you. There are also serious safety issues when servicing TV sets and electrical appliances.

--

JANA _____

-Almazick- wrote:

"What should I check for?" The nearest servicer in the Yellow Pages and ask them what they'd charge to correct this. If the first and only thing you try is to turn things that move to repair this, then guiding you to the probable circuit would most likely turn the tv into dumpster fodder. That's a nice product. Spend a little and get it fixed right.

Then stop touching it already.

Okay if the rest of you all are done with your immature flame war, I can say through all my experience that is is definitely a bad capacitor either in the vertical or power supply area. No cap should be getting too hot, so this may be a symptom of the main voiltage bias being out of range. Look inwside the back cover for test-points and check that main B+ voltage is within 5% of spec (if given).

So the guy wants to learn, noone becomes an expert from a book alone. If any of you people flaming were experts, you should already know that. While I agree that diagnosis comes before adjustments, and that some skill is required, he IS NOT FIXING YOUR EQUIPMENT, so get over it. If they do something wrong, it's on them, not you, in case you forgot....

Sheesh, seems people here are a bit too uppity about things that they have made into their own personal problem. Quit shutting out someone with an idea, everyone has to make mistakes to learn. You could all suggest politely that the focus control will not fix it. For those who want to know, I am self-taught on many a different area that you will never understand, and know more in many than all the book-smarts in the world.

8 years of college cannot teach what I have learned in as little as five seconds...

"Electromotive Guru" wrote in message news:448e6aa5$0$16332$ snipped-for-privacy@authen.yellow.readfreenews.net...

There is a difference between helping someone to learn safely, and being irresponsible. By saying that he had attempted to 'repair' his faulty television set, by twiddling controls whose function he understood nothing about, the OP demonstrated that he was not competent to be inside a television set with safety. Now you may think that is ok, but I think that if those of us who are properly qualified, and whose collective wisdom exceeds yours by many times, were to recommend that he continued to poke around inside an item of equipment that REALLY COULD KILL OR SERIOUSLY INJURE him, this would be irresponsible, rather than helpful.

For sure, we all learn by making mistakes, but you're not gonna learn a lot, if your first bad one puts you in the mortuary. In order to learn repair of TV sets, and similar equipment, safely, you need at least a mentor, who is fully qualified, and standing by your side watching your every move. You absolutely MUST understand the safety angles of what you are doing, otherwise, with a couple of repair successes under your belt, you will start to become a self-proclaimed self-taught *expert* who then goes on to carry out dangerous work on other people's equipment.

Whilst it is possible for qualified people to learn new techniques and hints and tips from groups such as this, it is not possible for total amateurs to learn arts such as TV repair, safely. Would you seriously suggest that someone should try SCUBA diving, or sky diving, or mountain climbing or racecar driving, without having been practically taught by someone who knows how to do it safely ? No, of course not, and anyone who believes seriously that electricity is not equally dangerous, is a fool.

No one has been *flamed* on here. Perhaps one or two of the comments were a little less than polite, but if you think that is flaming, then you have lived a sheltered internet life. Everyone from amateurs to professionals are welcome on here, and will normally recive good and valid advice, but don't expect those of us who take a responsible attitude to safety, to encourage either those who don't, or those who have no knowledge of such matters.

Arfa

Now now, Arfa! 'Electromotive Guru' is obviously someone the group should look up to. After all, he advises someone who knows so little about basic physics that he doesn't know what a focus adjustment does, to, and I quote:

"Look inwside the back cover for test-points and check that main B+ voltage is within 5% of spec" (because) "this may be a symptom of the main voiltage bias being out of range"

Obviously good advice ;-) He also thinks it's good advice for a non-savvy consumer to take the back off his set and poke around inside so he can 'learn', without having even the most basic knowledge of electronics.

By his reasoning- my 13 year old daughter knows what focus means, and it's not just a car made by Ford, so she must be even more qualified than the OP to poke around inside a TV! Next time the TV breaks I might give her a service manual and a soldering iron and let her fix it for me. It's a nice RPTV so plenty of room for her to crawl inside and measure the 'main bias voltage'. I wouldn't want to deprive her of a learning experience after all!

Dave

Hello Dave D, I see your point regarding your 13 year old daughter knows what focus means and that's good but you need to learn how to read first before you flame anyone. If you read my original post you can find "I removed the tv rear cover and found only 2 knobs for Focus and Screen and they won't solve the problem." I do know what focus and screen means too but I did not say that I was tweaking them or did not know what it was. What I meant that I found only 2 knobs and it won't solve the problem because they have nothing to do with the problem I had (vertical deflection output). In older tv's used to be knobs behind the cover or small holes for vertical and horizontal adjustments. You assumed that I did not know what focus is and made something out of nothing. Anyway let's just stop arguing and stop putting people down. If people ask for advice, let's just give them because you don't know what they know and their experiences. Just like Electromotive Guru said, him and me are self-taught on many a different area that you won't have any idea how to fix it. In some areas I'm more stronger and some weaker and when I ask people for advice who knows more than me I don't really want to listen flames because I can bet you ask questions in other boards and you don't want people flaming you. I used to be on boards a long time ago helping people with cars, satellite dishes, operating systems, computer hardware and web designers because I'm good at it but I never made any flames. Don't like the question just go to the next one, simply ignore them. People always make a mistake with a bad description just like I did but it doesn't mean you are better than me because you really don't know me. On the other hand I fixed the tv and it only took me about 30 minutes. As you can see people it takes less time to fix something with a proper answer than reading all that flaming and your bad opinions which makes me sick. If you don't like something it doesn't mean you have to start flaming people just ignore and go to the next post. It makes our life's a lot easier. A big thanks to people who pointed me to the right direction: Sam Goldwasser, Franc Zabkar, Jana and Electromotive Guru.

"Dave D" wrote in message news: snipped-for-privacy@pipex.net...

OK, I accept I have misunderstood you, but please understand that "and they won't solve the problem." can also mean you tried them to no avail. Damn the English language, ambiguity is too common!

I am sorry you didn't consider my advice to be helpful, and indeed considered it to be flaming. However, we are not mind readers. How was I to know you were techinically minded? You certainly didn't give that impression from your OP which was vague and admitted lack of knowledge of the working of TVs, and clearly I'm not the only one who thought that.

Generally, if people come here with intelligent questions and can provide troubleshooting info, they will get intelligent answers. If they come here and give the impression that they know nothing (as you did- you said you wanted to learn) and ask questions like 'my TV went funny, which part do I change?' (extreme example) then they will often be disappointed.

If you read back over my posts you'll find that in actual fact I did give an answer, despite what you think. Furthermore, though it wasn't what you wanted to hear, my advice to stay away from TVs until you get up to speed on LV equipment was sound and I had your interests at heart. I could have said 'dive in with both hands while it's on, and make sure you're a bit damp', but no- I was simply concerned for your safety. The advice was given based on the impression of your abilities *you* created here, and I stand by it.

Anyhoo, no offence intended- it was just banter. Good luck with the repair.

Dave

I fixed the tv by the information I received from Franc Zabkar. I found datasheet then found similar schematic for my tv. Changed 1 capacitor turned on the tv and everything was working.