Your problem is the yoke itself. Check for open yoke vertical windings or the coupling capacitor, or check for open ,shot or leaky oscillator transistor. Replace all found defects. Try not to open your unit if not familiar of doing so, let the expert technician to do so. Am sure this will solve your problem. Pls. reurn feedback so I will know or any additional infos we can advise. Thanks,,
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
It sounds that the main power supply section to your TV has the fault. The horizontal thik lines that appears crawling down across the screen should be of video 'HUM'. Have you replaced the main filter capacitor at the power supply section? If not, replace it along with the main rectifier. The AC power is rectifed by a bridge and applied ot this main filter capcitor. It will have a capacitance value between 120 to 350MFD 450VDC. Check this section. Measure the rectifed DC voltage acorss this main filter capacitor. It should be around 350VDC, if your home power supply line is 220VAC. If it is 110AC, this DC voltage will be around 165VDC; and it should be. If rectified DC voltage found lower than the input AC voltage, replace the rectifier bridge. In some sets, this bridge section have four diodes. Some other circuits, a bridge rectifier stalk may be used.
The line is there because the vertical deflection unit - the one that spreads that line across the entire screen to form the image - has failed. Replacing it is a job for a professional, or at least an experienced amateur, and the parts will be quite difficult to find for such an old tv .
You aren't specsificly dercribe yor tv set. For common TV horizontal problem ;i.e : White line accross the horizontal screen, horizontal band,etc..it's can solved by replacing the IC Vertical/Transistor, and olso to replace the cap nearest the IC.
For common TV Vertical Problem :i.e : White line at the center of the screen (top to bottom),Vertical band,etc...It's can cure by Replacing the Horizontal IC/Transistor,and offcurse the cap's.
If what you are trying to say is that you have a 1/4 inch horizontal line across your screen, this means that something in your vertical deflection circuit has failed. This could be the vertical oscillator, the vertical output processor, the vertical coupling capacitor, or the vertical section of the yoke transformer.
If what you are talking about is a vertical line from top to bottom then you are possibly talking about a failed horizontal section of the yoke transformer.
Why so little about the horizontal section of the yoke? That is because if the horizontal section fails completely then you would lose high voltage and no line would be present because you would not have raster (screen light).
In any even check the yoke transformer first. Then work back from there.
You have a failure in the vertical deflection circuit. This could be either a bad vertical chip, the power supply that runs the chip or a bad capacitor in that circuit. This is usually a repair best left to a professional. There is a small possibility that it could be bad solder connections. If genlty tapping the unit temporarily solves the issue you can try and resolder the pins on the vertical chip LA7841 is the part number. There is also a resistor 1 ohm 1 watt. If that resistor is open you can assume the IC is bad
It sounds like a vertical deflection problem. You mentioned you had a white HORIZONTAL LINE in the middle of the screen. If this line runs from left to right across the screen it's in Verticla deflection. If it runs from top to bottom, it's in Horizontal deflection. I am assuming the problem is a Vertical deflaecion problem. The repairs necessary are most likley to replace the vertical capacitors or the verticla deflection chip.
NC Electronic Mills, Wyo USA
A set that has only a 1/2 inch bright line through the middle of the picture, from left to right, has a vertical output IC that is not working correctly. If the 1/2 inch line is in the middle but going up and down, then the horizontal yoke circuit has stopped working. These are problems which should be looked at by a qualified tech, but if the set was purchased 6 months ago then it should still be under the manufacturer's warranty.