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    Sony STR-DB795 dim vfd display

    SO, i bought an amp from ebay, they said their kid hit the display with something and then it wouldnt switch on.

    The whole circuit board with the display and buttons on it was cracked right near the ribbon connector is, severing all the traces

    Anyway, after 4 hours of surgery i have got all the traces mended but the display is dim, pretty sure it has nothing to do with my wiring as everything works fine, all buttons work.

    I have heard that vfd displays go dim after time, so is there anything i can do to make it brighter?
    Attached Files
    Do NOT touch heatsinks when testing for voltages as they may be LIVE!

    #2
    Re: Sony STR-DB795 dim vfd display

    Just checked the pinouts and the -28v is only at -18v?

    This comes from another board on the other side of the ribbon.
    Do NOT touch heatsinks when testing for voltages as they may be LIVE!

    Comment


      #3
      Re: Sony STR-DB795 dim vfd display

      has it got a dimming function on it? heres a link to the manual
      http://www.sony.co.uk/product/home-c...95/manuals#tab

      Comment


        #4
        Re: Sony STR-DB795 dim vfd display

        Impressive surgery!

        -28V is used for the VFD, so it is important that it is correct.
        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


          #5
          Re: Sony STR-DB795 dim vfd display

          yh its got dimming function but its on full brightness , and thanks tom

          ive followed the -28v witch is -18v all the way to the power supply so the problem must be there.

          i will upload pics soon

          thanks
          Do NOT touch heatsinks when testing for voltages as they may be LIVE!

          Comment


            #6
            Re: Sony STR-DB795 dim vfd display

            service manual

            Comment


              #7
              Re: Sony STR-DB795 dim vfd display

              Thank you Vince.

              Here is a few more pics of my handy work for those who like it ghetto

              Also included is some pics of the psu, i have marked the pin and some components that lead to the pin.

              Also a pic or 2 of how dim it is.
              Attached Files
              Do NOT touch heatsinks when testing for voltages as they may be LIVE!

              Comment


                #8
                Re: Sony STR-DB795 dim vfd display

                Just read the schematic and it says that -18.6 is what it should be?

                So what else can i try?

                The vfd heater voltage is 5vac so that seems normal too?
                Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                Comment


                  #9
                  Re: Sony STR-DB795 dim vfd display

                  Hmm... VFD voltage is normally 6.3VAC but 5VAC might be OK.
                  Where is -28V marked?
                  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


                    #10
                    Re: Sony STR-DB795 dim vfd display

                    It is marked as -28v (fl) On the psu, it then goes to the digital board where it is also marked -28v, then from there it goes via i thin ribbon cable to the front display board, also marked as -28v.

                    But the service manual states it should be -18.6v (Page 51, written in red), which it is, also it goes through a 25v 100uf cap, so it cant be -28v?
                    Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                    Comment


                      #11
                      Re: Sony STR-DB795 dim vfd display

                      May just be a typo, then. When they draw the schematic they could have written -28V which would have been put on all boards.

                      The display could be worn out.
                      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


                        #12
                        Re: Sony STR-DB795 dim vfd display

                        So does the dimming function has any affect?
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #13
                          Re: Sony STR-DB795 dim vfd display

                          yes, the dimmer function dims it more.

                          my current Sony receiver is much older and the display is fine?

                          shame really as I want to replace the 5.1 I have for this 7.1 amp, just don't think I could live with a dull display.
                          Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                          Comment


                            #14
                            Re: Sony STR-DB795 dim vfd display

                            Replaced a few caps on the vfd line with no change in brightness, gonna keep it anyway, sell my db830.

                            opened up the db830 to take some readings but it uses +32 volts instead of -18.6v like the db795.

                            the vfd heater is the same at 5Vac, so it must be like You said, it's just dimmed through usage.
                            Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                            Comment


                              #15
                              Re: Sony STR-DB795 dim vfd display

                              Found a sort of work around

                              The screen/bezel that sits in front of the vfd had a lining on it so you cant see the vfd unless it was illuminated, anyway, i have scraped that lining off and now i can see my vfd even during the day
                              Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                              Comment


                                #16
                                Re: Sony STR-DB795 dim vfd display

                                Any progress with this old issue?

                                Comment

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