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I have a dead tv make konka model kp2905qyt

130 volt present on collector of horizontal output transsistor. but no EHT. The horizontal output transistor is ok. and when removed it seems horiz.. drive is ok.please help

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  • Televison & ... Master
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Check the frequency of oscillation at the base of horizontal output transistor. It should be around 15.6KHz. If there is no frequency, the horizontal osciallator jungle IC should be suspected.

Posted on Nov 29, 2012

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Posted on Jan 02, 2017

techman
  • 3130 Answers

SOURCE: T.V. wont turn on

But my freind, If the set had a cold and hot chassis, it could be he is not measuring the voltage from the cold ground and therfore would be a normal reading?

Posted on Oct 10, 2006

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SOURCE: TV turn off by itself

The easiest way to describe this is to measure the center pin to either outer pin. If either combination reads shorted, that is the problem.

Dan

Posted on Sep 03, 2008

brownline45
  • 310 Answers

SOURCE: prima model number cv1311 will not power up

good day. there are some parts to be tested. just resolder all pins of jungle ic. make sure that the board has no loose connection, try to check them all. then try to on your tv.

Posted on Jun 21, 2010

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1 Answer

My rca, when started, the sound come on but not the picture


Hello

Either your RCA tvs horizontal oscillator section or it LOT [Line Output Transistor} has some trouble. You just open your TV and check the voltage at the LOT pin. It should be around 112VDC or so. Check the voltage at its line drive transformer also. It is a small transformer diretly soldered on to the main board, and can be located very close to the above said LOT. Check voltage at its primay side , and if you have a digital multimeter capable of measuring frequency, check the frequency at this point. It should come around 15500Hz or so, without video signal. As far as sond is OK, all othere sections, ie video IF, Tuner Audio output and so, are working properly, only horizontal output is not. Check the horizontal output transistor, which drives the LOT, can be located very near to the LOT screwed onto a metal heatsink. If it collector to emitter or collector to base junction has some leak, it won't work properly, LOT will not work, and there will be no EHT [Extra High Tension], and will be no screen at all. Check these. If you wants anymore asistance from me, get me through Fixya. The fault with your TV is no horizontal sweep. OK.

Jan 08, 2011 | RCA F27442 27" TV

1 Answer

Power ok but not eht function


Hello

If you have tested the secondary section of the SMPS power supply of your Sony TV, amd found it OK I thinks, and posts this solution.

If the secondary supply rail 125VDC is found ok, just goto to the Horizontal Output Transformer, a small transformer diretly soldered on tho the main board, very near to the Line Output Transformer [LOT], and its secondary winding is connected to the base of the line output transistor, which in turn drives the LOT said above, generates EHT you described.
The base of the line output transitor must get appropriate frequency to switch on and off. This frequenct is gerally comes to 15625Hz. Just measure the voltage across the primary winding of the above said line driver transformer, which can be a possiblity open winding. Check the voltage at the collector point of the line drive transitor connected ti the one end of the primary winding is easy. Then check the voltage at the other end of that winding. There must be a little difference of 2VDC or so, if the line drive section is working, and fault is after that section, that is line output section. If you have a digital multimeter capable of measuring frequency, measure the frequency of the collector point of line drive transtor, and find out whether there is 15625Hz or near to this frequency comming out. Never touch the multimeter prob to the collector of Horizontal Outout Transistor, while it is working. Your meter will get damaged.
Line output section, contains tha LOT said above and line output transitor. If the Line Output Transistor has some sort of leak, normally collector to base leak, it will not drive the LOT to produce EHT and it wlii heat up also.
Just check it heat effect, after switching the set on for a short period of time, say 30 seconds ro so. If it heats up abnormally, suspect the line output transistor and LOT. You just replace the line output transistor first, with same type and number. If it doesn't retify your problem, LOT said abve is faulty, and it also should be replaced with same type and number.
If you have to replace the horizontal output transistor, and the LOT said abve, insist on orginal, and not replace it with a susbstityution, as these are critical components in all TVs..
If you need further assistance, get me through Fixya, and be free to conact me. Ok

Nov 29, 2010 | Sony KV-XA21M61 21" TV

1 Answer

Hi,i just change the flyback of my sony KV-21JSR1 ,but still it's not working,it has sound(audio volume is working)but no raster,the flyback that i bought is only generic,because originals are not...


Hello
Have you a digital multimter that can count frequency. if so the testing will be easier to you. Just count the requency at the collector point of horizontal driver transistor, or at the base of horizontal output transistor. it should come around 15.625KHz [15625Hz]. When the tv wors with no signal this frequency may differ, but come very near to it. When it synchronises with a picture, it won't vary and will remain constant.
If you have no frequency counter, just measure the voltage at the collector of horizontal driver transistor. It will be normally connected to the primary winding of the line drive transformer, which is very small transformer on the PCB. Then check the voltage at the other end of that trnsformer, where supply to the collector of the above said trasistor is given. The voltage at the collector side of the winding and at the other side of the winding must have some difference, if the frequency said above is present, and drive transistor is working.
If there is no voltage, check the resistor connected to that winding to main power supply for open, or the capacitor fitted to that point to negative for short,,, or check the continuity of the driver trasformer primary winding itself, or a short between its primary and secondary windings.
If all of there are ok, and still LOT doesn't works, check the supply voltage to lot. Being a 21" TV, its LOT supply voltage comes upto 125VDC or so. If it is also there, try replacing the horizontal output transistor. It also doesn't help, the Line Output Transformer you have replaced is not the exact match. Sony EHT transformers are critical in construction and in winding. Keep it in mind, and buy an another. If you need any assistance freom me, don't hesitate, ask me through Fixya. OK.

Nov 05, 2010 | Sony Televison & Video

3 Answers

HORIZONTAL OUTPUT TRNSISTOR SHORTS WHEN POWER ON TV


ALL the next is with the tv unplugged (NO NO power)
  • resold the jungle (video processor) all around
  • following the horizontal drive pulse path and arriving to the horizontal area just after the horizontal transformer and in the base of the horizontal DRIVER there is a electrolytic capacitor (if this chassis uses this one,) Change it (maybe is dry)
  • solder all components i just told you in the last step. horizontal driver, transformer, etc
  • remember:
  • if a transistor is blowing with no reason (there is a reason: the collector receives 130 volts but cannot hold it forever, It has to be in some place. if the switching pulse doesn't arrive to it the transistor throws this 130 volts and burning itself. i hope it is help full.

Apr 15, 2009 | Televison & Video

5 Answers

Help for TCL Brand of tv


I WANT THE SERVICE MODE CODE FOR MODEL NO: DP21E101 TCL TV 21"

Jun 15, 2008 | LG 30FS1D TV

1 Answer

Turns on light comes on but no sound and no picture


verify your b+ voltage on collector of horizontal output transistor 7405 and if 130 volts is missing or way off go to power supply circuit and verify voltage on pin 14 of ic 7511 and if there is not approx 150 volts present should replace that ic and startup capacitor 2511 and opto isolator 7513. if 130 volts is present on collector of 7405 then scope signal on 7404 and if not clean signal replace micro processor

May 27, 2008 | Philips 26PW6341 26" TV

1 Answer

Disney TV prob you helped me with.


I could not find anything schematic for your TV.
I would suggest to check the horizontal transistor, if the transistor is OK; check the voltage at the collector. NOTE: be very careful when measuring this voltage, you should get about 130 VDC.
If that voltage is present, you might have a defective flyback transformer.

Mar 25, 2008 | Disney DTD1363-CAR 13" TV/DVD

1 Answer

Tv not powering up


What voltage is present at the collector of the horizontal output transister? If the same 102 volts then you have no horizontal drive.

Mar 22, 2007 | Daewoo DTQ-20N2FC TV

2 Answers

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.

Oct 09, 2006 | Sanyo DS27510 27" TV

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