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(CRT)QUADRO CTV-5525 ,Horizontal white lines problem

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    (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

    Hello, so I have this TV with the problem that on screen are these white lines .. so i tired to look around board but everything seems okay except some bad soldering joints that was resolder but problem is still here, this is not a priority repair i just what to learn something about CRT TV's. About CRT TV's I know only basic working principle from school. So thanks guys i can post more pictures of board,electron gun and so on.
    Thanks
    Attached Files

    #2
    Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

    This is usually caused by a fault in the circuit that blanks the electron beam during the vertical re-trace stage of the CRT scanning.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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      #3
      Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

      So fault is probably in that circuit , where to find that part of circuit and is there any special part to look for?

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        #4
        Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

        you could always check and see if the screen adjustment on the back of the TV if it's accessible has not been tampered with more known as G2 adjustment I've seen people over drive these because the CRT is starting to get weak.
        Did I leave the soldering iron on?

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          #5
          Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

          on the flyback transformer are two knobs for adjustment focus and brightness

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            #6
            Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

            Try the brightness control first.
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

            Comment


              #7
              Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

              I believe your horizontal frequency is too high. Check the oscillator circuit. Should be 17,750 hz if I remember correctly.
              Last edited by Ltank; 12-16-2014, 12:08 AM.

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                #8
                Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                try to adjust knobs on flyback transformer no results only changing brightness and sharpness, huh,i can't measure frequency because i dont have an oscilloscope :/ i can change parts in oscillator circuit
                Last edited by microcont; 12-16-2014, 02:44 PM.

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                  #9
                  Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                  Look for a capacitor near the flyback or near the vertical circuit. should be a low value 2.2 3.3 10 or 22 uf at a high voltage 200, 250 volts, It won't look bad but most likely is, ther may also be a couple bad caps arount the vertical output that could be weak
                  Looks like it could be C706 1uf 250v
                  Last edited by R_J; 12-16-2014, 03:31 PM.

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                    #10
                    Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                    at the output to the electron gun board it is 10uF 250V. It is very dusty trying to clean that..
                    Attached Files
                    Last edited by microcont; 12-16-2014, 03:57 PM.

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                      #11
                      Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                      vertical IC is:
                      HTML Code:
                      http://www.rem-tv.odessa.ua/datasheets/v_def/LA7840.pdf

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                        #12
                        Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                        It looks like this might be a closer diagram, the dust won't cause the problem. on this diagram its c303
                        Attached Files

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                          #13
                          Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                          I change that cap, but no results still is the same screen with lines as before

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                            #14
                            Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                            TV works after testing resistor R322 0.68Ohm to find out that it is an open circuit , and i replaced R322 with new 0.51Ohms. It works fine.
                            Thanks guys for help

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                              #15
                              Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                              If that cap C303 was bad, then there may have been excesive current through d305 causing R322 to open, Bet the cap was bad I have replaced this cap. in more sets than I could count for having retrace lines in the picture.
                              Last edited by R_J; 12-17-2014, 03:17 PM.

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                                #16
                                Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                                Yep, resistors rarely fail without obvious cause.
                                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                Comment


                                  #17
                                  Re: (CRT)QUADRO CTV-5525 ,Horizontal white lines problem

                                  Now it is new C303 and R322 hehe thanks for the explanation , i will remember that fault on TVs

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