TV PROBLEM philips tv, model 21pt3324/79 keeps on shorting (short circuit) the line output transister (bu11 af), and then the set starts to give a squeking sound, what could be the cause?

Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/

check the capacitor on power regulator area if there is puffed capacitor(bursted).blink means time delays but the power is not sufficient to stabilize because of a faulty capacitors and it triggers to stop the start kick.(some cases arehaving busted horizontal out transistors or shorted.

Hi

Your tv set may have a short circuit both in the power supply and horizontal output stage. The first approach I suggest is to check the rectifier fast diode in the line supply (90/100V) for short. This model is prone to burn this component and may be associated with some problem in the horizontal output or even in the RGB output.
I would like to point out that this task require a technician as should be supported with a schematic of this model.
If this is helpful, I shall be glad.
Sully

Check for any short circuit at the horizontal output section circuit. Check all the non-electrolytic capacitors used there. Replace all suspected ones with same capacitance value. A winding short in the windings of deflection yoke, will too make the horizontal output transistor to get overheated. If so, there is no other way than replace the deflection yoke. If you wish to get more details, check the site linked here. http://electronicshelponline.blogspot.com/
Pull up previous posts by its left sidebar, or type in the brand name and model number to of your set, to its search box, and press 'Enter' or view it in Mosaic / Timeslide option.

The line output section circuit works as soon as you switch ON the TV, and then come across any short circuit inside the set, and shuts off. That is happening here now. You must check the set, and trace out this shorted or damaged component/s. If you're sound in electronics, download the repair manual to this model set by internet, and carry on. If you're not sound in electronics, contact any service technician. If you wish to get some details about repair work, check the site linked here. http://electronicshelponline.blogspot.com/
Pull up previous posts or type in the brand name and model number to of your set, to its search box, and press 'Enter' or view it in Mosaic / Timeslide option.

Hello

Your Philips Tvs line output section has some trouble with it. All philips power supply circuits are so designed that, even a small short circuit in the ciruit board occurs, the power regulator will sense it, and the entire system will shut down, and that is happening now in your TV.

You just start with the horizontal output transistor, fitted very close to Line Output Transformer [LOT], for any short. You must desolder it out from the circuit for this check, and check it for collector to emitter leak. If this will happen, the main regulated power supply ie 120VDC, will gets shorted through this transistor, cause a dead short circuit. If it is shorted, you must find out the reason for that short.

If LOT said above has damaged, this transitor will also get shorted. In otherwords, if LOT is damaged, its driver transitor,will also will get leaky. You just replace this transitor with an identical one. Switch on the tv for a while, say 10 seconds or so, check its heat effect. If it heats up abnormally, surely LOT has damaged, and you should replace it also with an identical type and number. Ok

100k ground from ic pin replece 3 electrolytic cap . Adjust preset for 95v if it isphilips tv

please check flyback transformer for short
good luck

Check horizontal output transister short. Check AC fuse open. If it is open check powersupply section any short circuit and check PTC.

Your tv does not need a reset,what happened something went bad inside the set and it needs to be replaced,if you are familiar with tv service you can start by checking the horizontal output transistor for a short,if he went bad it likely made the fuse or safety resistor open.If you are not too familiar with tv service be safe and call for assistance froma servicer.If you decide to go in looking for problems make sure the set is not plug in.Let Us know how it goes or if you need more information.