I am from Pakistan 58years old I am a retired person and doing TV repairing as hobby I have a Philips 21" TV model no 21pt2682/65r problem is TV is totally dead there is no short S.M.P.S is not working please help me.
Very very best regards
Glad to meet you and happy to hear from Pakistan. With regard to the TV you are repairing you have not given me any fact you have already gathered in order for me to make any conclusions. I suggest you read this article on troubleshooting smps on my site and I am sure it will help you.
Dead symptoms on TVs are the easiest to solve and they are mostly power problems
Thank you very for the reply I know that your time is very important but you are replying too much emails from the world. I have another TV Philips model no: PT2682/65R when I power on TV flub flubs but no raster and no sound.
This could point to a short on the secondary side of the power supply. Especially the fly back or surrounding components.
The other TV Nobel 29E25D chines TV screen cuts from horizontal side like 1 inch from both sides
1. If the screen is less in width this means a problem on the horizontal circuits. Especially the snubber capacitor has lost some value so I suggest you replace the snubber capacitor directly and see if this problem will go.
2. If the screen is less height this means a problem with the vertical circuit.
I hope you will not irritate and give me detailed answer that what should I do.
My friend Hameed, if you look at the way I have been supporting my customers you will realize that they are the ones who supply the most important facts because they are on the ground and then I analyze them and make some conclusion based on the facts provided.. The more info they provide the higher the chances of the repair will be successful.
Again my aim is not to give them the fish but to show them how to fish…so that even if they get a challenging repair in future they can always handle it.
As you told me that some short in secondary side I checked again and found a capacitor 680pf parallel to the 95 volt supply diode in secondary side was shorted after replacing the capacitor TV come alive but after one hour TV come in standby mode I checked all the dc voltages all is perfect after 15 minute later I switched it again TV starts normal but after fifteen minutes go to standby can you help. And what is the snubber capicitor can you explain.
First let me take up your last question (And what is the snubber capacitor can you explain.)
This capacitor is usually rated between 1200Volts-2000volts, it has one leg on H.O.T collector and the other leg on the ground.
As the name implies snubber capacitor is used to suppress (snub) induced high voltages by the collapsing magnetic field in the flyback transformer primary winding which could otherwise lead to destruction of the Horizontal output transistor (HOT).
That is why sometimes this capacitor is also referred to as "safety capacitor". If this capacitor is open or is removed from the circuit it will cause instant destruction of H.O.T transistor.
If the TV is going in standby after 15 minutes it means there is something which is getting overheated. let it run for the fifteen minutes and switch it off and remove the power cable from the power outlet and touch components around the flyback and see which is becoming too hot...whatever component is getting very hot is most probably the faulty one. Be sure also to touch the top of those big capacitors on the secondary side and see if any if getting hot. If any is getting hot just replace it directly.