Touch the input pin of the vertical IC, by the blade of the screwdriver, and see whether there is a tendency to change with width of the horizontal line on screen. If so, check and replace the horizontal, video if, vertical oscillator jungle IC. Check the frequency to the input of the vertical scan IC, with a frequency meter. If there is frequency, and still no vertical scan output, check the yoke connection, and make sure that it has no open circuit. If you wish to get some details, http://electronicshelponline.blogspot.com/ Pull up older posts.
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Touch the input pin of the vertical IC, by the blade of the screwdriver, and see whether there is a tendency to change with width of the horizontal line on screen. If so, check and replace the horizontal, video if, vertical oscillator jungle IC. Check the frequency to the input of the vertical scan IC, with a frequency meter. If there is frequency, and still no vertical scan output, check the yoke connection, and make sure that it has no open circuit. If you wish to get some details, http://electronicshelponline.blogspot.com/ Pull up older posts.