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Crt tv - click sound turn off and i start again

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juanmotta

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Hello, my name is Juan Motta, I am new to the forum, I would like to consult them because I have a problem with a Panasonic tv tc-20s10La, I already fixed a problems, but what happens now is that if I turn it off and try to turn it on again, it starts to make a click noise, click and it does not turn on, after several days it turns on. It has burned the demagnetizer, I ordered it but it's going to take a while. I would like to know if it is possible that if the demagnetizer is burned, do not turn on the TV after being turned on. I already change the source capacitor and some more.

Thanks

Juan motta
 

betwixt

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If by 'demagnetizer' you mean the degaussing coil around the CRT, if it burns it means the thermistor controlling its current is damaged but that would not cause the PSU to shut down. If the coil really did burn, it has most likely left a carbon deposit around the CRT which could be arcing the EHT around the glass. That would cause a loud pop noise and shut it down, causing the symptoms you describe. Look around the CRT, especially around the plastic high voltage connector, it should be clean and firmly fitted to the connector in the glass.

If the plastic cap is damaged it must be replaced, if the glass is dirty it must be cleaned. Be VERY careful if you remove the cap, before pulling it off, wire a long thin screwdriver to the metal shield around the CRT then slide the screwdriver under the edge of the cap until it meets the metal connector. Leave it there for a few minutes then remove the screwdriver and pull the cap away from the glass. There are very high voltages (maybe more than 25,000V) on the CRT and you really don't want to touch them! NEVER switch the power on without the cap refitted!

Brian.
 

juanmotta

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If by 'demagnetizer' you mean the degaussing coil around the CRT, if it burns it means the thermistor controlling its current is damaged but that would not cause the PSU to shut down. If the coil really did burn, it has most likely left a carbon deposit around the CRT which could be arcing the EHT around the glass. That would cause a loud pop noise and shut it down, causing the symptoms you describe. Look around the CRT, especially around the plastic high voltage connector, it should be clean and firmly fitted to the connector in the glass.

If the plastic cap is damaged it must be replaced, if the glass is dirty it must be cleaned. Be VERY careful if you remove the cap, before pulling it off, wire a long thin screwdriver to the metal shield around the CRT then slide the screwdriver under the edge of the cap until it meets the metal connector. Leave it there for a few minutes then remove the screwdriver and pull the cap away from the glass. There are very high voltages (maybe more than 25,000V) on the CRT and you really don't want to touch them! NEVER switch the power on without the cap refitted!

Brian.

Thanks for your answer!!!, sorry if I have not expressed myself well, the TV does not turn off, when I turn it off, then it does not turn on and it starts to click, and yes is the degaussing coil burned.
 

BradtheRad

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Don't some tv's perform degaussing briefly every time you turn it on? Then if your degaussing circuit draws overmuch current, the power supply droops. The tv may just barely turn on, causing the supply to cut out. Then the supply voltage rises enough to turn on again. Your description sounds as though this action repeats indefinitely, correct?
 

betwixt

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Degaussing circuits run directly from the AC line (the coil current has to be diminishing AC for it to work) so they can't be fed after the PSU. Droop is unlikely to be the cause.

I really need to know where the click comes from. Given the burning around the CRT I assumed it was EHT flash-over.
Juanmotta, do you hear just one click or does the click keep repeating?

Brian.
 

juanmotta

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Yes, the problem is when i turn off the tv, and trie to turn on again, the clicking continues indefinitely. When I disarmed the TV, I was infested with cockroaches and there were many in the area of degaussing component burned.
 

ads-ee

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There are very high voltages (maybe more than 25,000V) on the CRT and you really don't want to touch them! NEVER switch the power on without the cap refitted!.
the TV, I was infested with cockroaches and there were many in the area of degaussing component burned.
Gives the original meaning to a circuit with "bugs". Those cockroaches should have read betwixt's posts before working on the CRT, or using it as their "home".
 

betwixt

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I know its a bit off topic but I was once given a stereo system to repair with the complaint it had gone quiet and squeaky. Opening the loudspeaker boxes revealed there were no cones on the loudspeakers but a lot of dead, well fed cockroaches in the bottom of the boxes!

Juanmotta, it sounds as though the clicking may be the power supply starting up, tripping and restarting again. It could be so many things it isn't possible to suggest them all here. Do you have any test equipment you can use if we ask for measurements?

Brian.
 

juanmotta

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I know its a bit off topic but I was once given a stereo system to repair with the complaint it had gone quiet and squeaky. Opening the loudspeaker boxes revealed there were no cones on the loudspeakers but a lot of dead, well fed cockroaches in the bottom of the boxes!

Juanmotta, it sounds as though the clicking may be the power supply starting up, tripping and restarting again. It could be so many things it isn't possible to suggest them all here. Do you have any test equipment you can use if we ask for measurements?

Brian.
The only thing that i have is a multimeter. I have changed the deggauser and it stays the same.
 

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