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Re: T.V. wont turn on
The voltage might be low because is being loaded down,open the collector of the output transistor and measure the voltage again,if it goes up to 130 or the voltage is suppose to have you might be looking at a bad output transformer(flyback)there are other parts that can cause the loaded down voltage,the yoke can be one and capacitors in the deflection circuit,check to see if one of this caps is overheated (bubble)or cook,Be carefull if you open the collector when you measure the voltage,If you can try measuring the voltage somewhere else.Lets Us know if you need meore help.
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You're either losing high voltage or power supply is not producing the horizontal drive signal, Check for 130v on the collector of the horizontal output transistor, if you're missing your voltage, you have a power supply problem. If voltage is too high you have something open in the power supply such as a low value resistor. If its low, something is shorted in power supply, possibly voltage regulator ic.
Replace its Horizontal output Transistor. If the base-emitter junction has a leak inside it, this type of fault will occur. Before replacing it, check the main DC voltage to LOT [Line Output Transformer]. It should come around 102VDC. If there is not this much voltage, check the electrolytic filter capacitor connected across thie supply line to main negative for open or value developed. Replace the same is good. Till there is low voltage found, check the retifier diode that rectifies this 102 volt DC. If all the above are OK and still you get a stamp like raster, check the heat of the Horizontal Output Transistor described above. if it overheats, LOT is defective and should be replaced with same type and number. OK.
Check the LOT and Horizontal Output Transistor. If horizontal output transistor get shorted [collector to emitter or collector to base], this kind of fault will occur. Here there is nocollector to emitter short as B+ is ok. Check for collector to base leak. It is best to repalce the horizontal transistor with a new one, and switch on the Tv for a short while, say 10 seconds or so, and feel the heat of the replaced transistor. If it gets overheated, of LOT makes a whisiling of hissing sound, LOT is faulty, and shoul be replaced sith same type and number. OK.
The set has a shorted horizontal output transistor and possibly a bad high voltage transformer. The transistor can be checked with a DVM but the transformer has to have its impedance checked with a "ringer". Also solder all stages in the drive circuit of the horizontal transistor. The power supply is making the noises because of the short on the secondary side. Thanks for using fixya.
I suggest you look at the Horizontal output transistor, when it goes short the supply is in protection mode, it is pointless reading voltages at this stage, check the transistor located close to the Horizontal output (Flyback) transformer and normally mounted on a large heatsink. Check the caps in the primary power supply stage....hope that helps..Phil
try to check first if theres an output voltage in the wall outlet. if there is, you have a completely inoperative (dead) set.
this symptom is usually caused by a breakdown in the power supply circuit. in most modern receivers (transistorized and/or IC), it may also be caused by a breakdown in the horizontal deflection circuits (horizontal oscillator, pre-drive or drive circuits). this is because the supply voltages for the tuner, video intermidiate frequency (VIF), video amplifier, sound intermidiate frequency (SIF) and vertical output circuit are usually supplied by the horizontal output circuit. but again, if you are not inclined in this kind of job, better bring it to a qualified tv technician. good luck!
This is like a car running without a driver,the horizonatl output transistor has the voltage it needs but it does not have horizontal drive signal applied to the base of the horizonatl driver transistor,the driver transistor should have a signal coming from the signal processor where the signal is generated just to get give it to the driver this driver then it gives it to the output to energize the flyback and light up the picture tube and generate a few other supplies,158 volts are there because the output is not turn on,try measuring voltage somewere else in the set and not at the collector of the output,there is a b+supply that goes to the signal processor(8 to 12 volts),check to see if you have this voltage,I couldn't tell you the pins in the siganl processor IC without squematic,It seems you know your way around tv service but be careful when checking voltages.Let Us know if you need more information.