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One Horizontal Line In CRT Monitor Repaired

By on April 18, 2015
horizontal lines on monitors










I had a PC in my desk because a friend of mine brought it to me to do a Preventive Maintenance, then my little son asked me if he can play games. While he was playing the games suddenly my son asked me to come inside the room.

horizontal lines on monitor

When I got to the room, I saw the PC Monitor had a horizontal problem.

The brand of the Monitor was AOC Model No.: 7VlrA. This horizontal lines on monitor problem usually is due to the vertical section having dry joints.

horizontal lines in monitor

Note: I’m sorry for the dust in the room, but my home was under restoration at that time.

I confess that night I had no wishes to repair that Monitor, so the duty began the next day. The equipment was disassembled, some screws were taken out.

horizontal lines in monitors

Of course the culprit of this malfunction was the vertical circuit, and the main component in this circuit was the IC TDA 9302H (Vertical deflection output circuit).

vertical output ic

Most of the times this IC is not broken, only you have to check on the cold joints of the PCB.

vertical ic

As you can see in the photo above there were some cold joints in the pins of this IC and in the surrounding components as well. Look carefully at the PCB, it is bit darken in the vertical IC area (overheating). All of the vertical IC pins and surrounding components pins were re-soldered with fresh tin.

When the device was tested with the video signal from the PC (VGA port), look at the result in the below photo:

vertical ic output

Now I can say my little son is happy again because he can play his games in the PC.












This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.

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  1. Merlin Marquardt

    April 18, 2015 at 10:55 am


    • Humberto

      April 20, 2015 at 7:49 pm

      Thanks Merlin

  2. Robert Calk

    April 18, 2015 at 11:58 am

    Good job Humberto. You have a handsome son. I'm sure he will be a good Tech when he grows up.

    • Humberto

      April 20, 2015 at 7:51 pm

      Thanks Robert, he is a gift of God

    • Humberto

      April 20, 2015 at 8:16 pm

      I forgat saying to you he reaches 6 years old in June 15th.

      • Robert Calk

        April 21, 2015 at 2:50 am

        Enjoy him while you can because they grow up fast.

  3. BIRuk aweke

    April 18, 2015 at 12:45 pm

    Hi Mr.Humberto it is easy and good work have a nice day from ethiopia.

    • Humberto

      April 20, 2015 at 7:55 pm

      Thanks BIRuk, you are welcome; and have a nice day from Cuba

  4. Yogesh Panchal

    April 18, 2015 at 2:19 pm


    Polishing a skill is best practice thanks for sharing.

    • Humberto

      April 20, 2015 at 7:57 pm

      Hi Yogesh, and have a nice day.

  5. Mark

    April 18, 2015 at 2:33 pm

    Hey Humberto,
    Thanks for your article and expertise.
    I had a closer look at the back of the PCB and noticed that there were quite a few cold solder joints, especially near C602, C605, R607, J072 & Q416. You must have spent a bit of time making sure you had resoldered the surrounding area as well.
    Congratulations on a successful repair.

    • Humberto

      April 20, 2015 at 8:02 pm

      Hi Mark, as you could see there were a lot of cold solder joints, and it took me more time to re-solder them with fresh tin. The equipment was cleande too with pressured air.

  6. Amir Mukhtar

    April 20, 2015 at 1:01 pm

    Thanks you Mr. Humberto Rodriguez to sharing nice article on vertical section horizontal line fault.

    keep sharing

    Amir Mukhtar Ashrafi

    • Humberto

      April 20, 2015 at 8:03 pm

      Thanks Amir.

  7. Albert Hoekman

    April 20, 2015 at 10:58 pm

    Nice job Humberto!


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