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One Vertical Line In 29″ Hitachi TV Repaired

By on November 25, 2020
how to fix crt tv with one vertical line








how to fix crt tv with one vertical line

My customer told me that his 29″ Hitachi CRT TV had a vertical line at the center of the screen. In order to confirm the problem, I had to turn on the TV and check on the fault. Indeed it was one vertical line. In some other cases, when I turned On TV it was one horizontal line. One vertical line and one horizontal line problem were caused by different section in the TV. Once you have confirmed the fault then it would be easy to troubleshoot only on that problematic section.

Below is the photo of the internal circuit board of the TV and it was covered by dust. I need to clean it before start with my first troubleshooting procedures which was the visual inspection.

crt tv one vertical line

Since I already knew the problem, I checked on the high voltage and horizontal width area. I found the safety capacitor was opened at the side layer. 

bad safety capacitor in crt tv

I proceeded to check all the corresponding components and found another component which was the diode already shorted.

See the photo below:

bad modulation diode in crt tv

There were only two components been replaced and when I turned On the set , I could see the display (noise). I let it run for few hours before sending the TV back to the customer. 

bad components replaced in crt tv hitachi

replacing modulation diode

hitachi CRT TV one vertical line fixed

Conclusion- Visual inspection is powerful. Don’t go straight to use meters to start checking the components as this could be a waste of your time. Always start with visual inspection first before go deep into troubleshooting such as voltage and signal checking, browse through components datasheet, using whatever home made gadgets you have and etc. Alright, will  see you again next time.


This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.

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  1. Albert van Bemmelen

    November 25, 2020 at 11:04 pm

    A first inspection of the failure indeed may save a lot of time and speed up the repair.
    That may also include using our fingers (searching for abnormal heat spots?), our nose (burnt smells?), and our ears (for wierd oscillating or sissing sounds, power supply in pulsing mode?). And like in this professional fixed repair, hearing the customer out on what he exactly experienced before or after the failure occurred, which here unmistakably was the horizontal deflection unit at fault.

  2. Yogesh Panchal

    November 26, 2020 at 3:17 pm

    Still CRT TV Fault finding is fun.....
    Good Job! Suranga.

  3. Parasuraman S

    November 27, 2020 at 8:53 pm

    Well done! Thanks for sharing!

  4. George Greenfield

    March 22, 2021 at 6:50 pm

    Great job with the visual inspection.

    We used to say "run off into the sunset with a scope probe in your hand" for the newbies that first thing they would do was gran a piece of test equipment without the visual look see.



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