Question about Televison & Video
The problem of your TV probably on the inverter board and on the cathode lamp itself.A deffective inverter board can cause the flickering of the screen same with the cathode lamp.Because the inverter board is a high voltage board,it affects the power supply because the inverterboard gets it's 24v supply from the power supply and gives an output of 120vac to the cathode lamps.to check this components you need to open the back cover of your TV to get into the parts.The inverter board is a board with small transformer on it this connects to the lamp which is situated at the top and bottom of the screen .
Try to resolder first the connectors of the inverter board also tighten the connectors of the lamp and the inverter.Have a visual inspection first on the board to see if there loose solder and burned parts replace if you found one...Pls post back if you need further trouble shooting guide or click the thumbs up button if this helps you good luck!
Posted on Nov 17, 2010
Thia may be due to low voltage from the power supply, usually leaky capacitor on the power supply will cause these symptoms. also check the inverter boards for puffy capacitor tops, mose caps are flat on their tips replace and you find with same value and voltage ratings.
Posted on Nov 16, 2010
Disconnect the LCD board from the main board and see if the back lights stay on with no flickering. If they stay on with no flickering then the LCD board is faulty and needs to be replaced or repaired. If the back lights still flicker with the LCD board disconnected from the main board then the inverter board AC output is faulty. If so, then its most likely one of the inverter boards 'step-up transformers' that has opened or developed an internal short. This will cause the back-lights not to work at all or will cause a strobing affect (flickering)
Posted on Nov 15, 2010
This is a fairly classic switchmode power supply problem. The protection circuitry inside the SMPSU, has sensed a severe potential problem, and is attempting the shutting of the set, down to avoid a fire, explosion, or both.
This set had developed a problem, that is so severe that the set must be shut down, (This set should be removed from the Power),
What is happening is the internal "Fault" that is causing the Protection Circuitry , to detect the problem and attempt to shut down the set, keeps restarting the set, because as soon as it shuts down, the "Faulty" component(s) cool down?, and the "Fault" ostensibly "Clears" so the PSU starts up again, only for the component(s) to heat up, whatever, again and fail, so it shuts down, and if left unattended, this would continue on until the part eventually failed.
Any fault that involves the power supply is usually quite serious, and needs a professional, usually, unless one is familiar with servicing current day, televisions.
And in my professional recommendation, you should get a "Quote" for repair, from, an, Approved Service Center. Now, this point is very important for a good result, Always contact, their "Local" or a, "Head Office" Cello, in your case. Ask them, for a referral to an authorised servicing center, where you ask for a "Quote". Now, when you get the information you want, then you can decide as to repair of replacement.
The reason we want an approved agent, is that way, all the engineers are trained on their own brand sets, they have seen almost all faults, and will get the job done quicker, and for less cost, and usually have parts on hand, also sometimes, there has been a service bulletin in issued and the repair may be subsided or even free. There are many, many, many reasons that display this symptom, one must work through the troubleshooting steps to isolate and identify, the Cause and repair that and any damage done.
Hi, well I applaud you for wanting to have a go, but you must make sure that you are starting in the right place, That is The Power Supply, as, if, that isn't right nothing else can be. But you simply cannot do anything without a Service Manual. In this it has everything one needs to repair the set. OK if it is shutting down, after that amount of time, of working and then faulting, then it is most definitely a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit" and you will soon,find that errant component. Now also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" now while that may be true in a few cases, a faulty Electrolytic Cap, or ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., Now Capacitors hate AC ripple, or Over Voltage. That's it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then that's a prime cause of failure. Resistors, hardly ever go faulty, and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be able to say.. "Oh that's the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish, a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins. The Tools you will need are A SERVICE MANUAL a Good Multimeter, a Signal generator, a Signal Tracer, pref an Oscilloscope, Soldering Iron, De-soldering iron, Probably, too, A SMT Hot Air desolderer (for the Surface Mount IC's), Compressed Air, An Anti-Static Wrist Strap, (MOST IMPORTANT, to prevent ESD), Cutters, Screwdrivers, sometimes, Torx, drivers too. Tweezers, are real handy, a magnifying glass, or eyepiece, a good strong white Light. OH, and you MUST have the original remote control too, (Sometimes one must obtain, purchase, a special "Servicing remote") as one needs this to "Program" the Computer in the TV, after, and during servicing, and to be able to put the TV, into "Service Mode" too.
Posted on Nov 15, 2010
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Posted on Jan 02, 2017
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