Focus Problem In CRT TV

By on August 3, 2013

I’m having some difficulty in repairing a 21″ sharp tv. It has focus problem so making it show blurred images. I have tried to adjust the focus knot of the flyback transformer but it remains the same. The components around the horizontal and vertical deflection stages are working fine.what are your suggestions sir. Could the flyback transformer, the stan-coil, or the CRT cause this. I’m confused please help me.


The problem usually is due to the either bad flyback transformer or bad CRT tube. If after adjustment of the focus knob at the flyback transformer and it slowly go blur again then most likely is the flyback problem.





  1. Frank

    August 20, 2015 at 3:10 am

    Hello sir am glad that through your posting am becoming a pro in crt tv repair am also happy to tell you that i fixed the colour patches problem i met. I only replaced the posistor and it worked fine but I met a crt tv SHAECO there is too much green color red is present and alittle blue white picture is displaying cream white. I changed all the RGB and all the three big resistors but no change.

    • Jestine Yong

      August 21, 2015 at 8:37 pm

      Hi Frank,

      Have you tried the menu setting? Have you checked the e-caps in the crt board?


  2. linclon

    July 16, 2016 at 6:12 pm

    hallo sir im busy repairing lg crt tv model cf29h30 it have a focus problem when i turnup the grid voltage at lopty the picture goes fuzzy uot of focus. when i turn down the grid voltage the picture is ok but very dark. tv have dual focus

    • Jestine Yong

      July 18, 2016 at 1:28 pm

      HI Lincoln,

      The picture could be weak already. If you have the high voltage probe then it would easy to detect if the flyback or the tube problem. Just measure the focus pin and see if it is low, normal or slowly goes up. It should be stable.


  3. A

    May 16, 2017 at 4:40 pm

    i also have a problem with mine..its sony crt..displays horizontal lines in the entire screen & th image is blured...

    • A

      May 16, 2017 at 4:47 pm

      The focus & brghtnes knobs are locate on th board attached to the they cant focus..nid asistance kindly

    • Jestine Yong

      May 18, 2017 at 9:09 pm

      Hi A,

      Please visit this link

      to solve horizontal line problem and if the focus can't be adjusted probably the tube could be weak already.



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