Viewsonic lcd VA1912wb

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • elbtax
    Senior Member
    • Apr 2008
    • 59

    #1

    Viewsonic lcd VA1912wb

    I was given the VA1912wb cause the green power light flashes off about every two secs. Screen is completely black. Checked with torch and see no image. Hooked to laptop and the os recognizes the monitor. Removed back cover and a 220uf,25v, 105c cap had the bottom blown out. Replaced all caps and checked solder joints on board. Soldered suspicious looking joints. When power applied the monitor exibits same problem as before. The fuse on the inverter board checks o.k. Any suggestions?
  • elbtax
    Senior Member
    • Apr 2008
    • 59

    #2
    Re: Viewsonic lcd VA1912wb

    Forgot to add pics....
    Attached Files

    Comment

    • tiggerific
      Member
      • Apr 2008
      • 21

      #3
      Re: Viewsonic lcd VA1912wb

      I'm guessing the pictures are from before you recapped the board since there are 3 caps definately bulging. The 4 chips near the transformers seem to have undergone a fair bit of thermal activity. One or more might be toast.

      Comment

      • elbtax
        Senior Member
        • Apr 2008
        • 59

        #4
        Re: Viewsonic lcd VA1912wb

        Thanks for the reply tiggerific. These pics are before the recap as you surmised. I started re-capping about a month ago. Someone gave me a 19" Gateway tft fpd1960 that the screen flashed with the Win logo and went off. The power light stayed green. Replaced caps & put a "touch" of solder around inductor joints. Works fine now. Also recapped an Acer S58m mobo. Works fine now. Anyway, can't do a lot with only a solder iron and a Dig MM.

        Thanks for your reply....

        Comment

        • Krankshaft
          Badcaps Legend
          • Jan 2007
          • 2328
          • USA

          #5
          Re: Viewsonic lcd VA1912wb

          I second to check those IC packages.

          They are probably driver transistors in a DIP package.

          Go to alldatasheet.com enter the part number on them and get the pinouts.

          Using the diode checker of your DMM should reveal any open shorts in the transistors.
          Elements of the past and the future combining to make something not quite as good as either.

          Comment

          • elbtax
            Senior Member
            • Apr 2008
            • 59

            #6
            Re: Viewsonic lcd VA1912wb

            Thanks for the reply KS. I will check for the pin-outs. I feel the problem is something simple i am missing. Hope so anyway..
            Thanks again..

            Comment

            • elbtax
              Senior Member
              • Apr 2008
              • 59

              #7
              Re: Viewsonic lcd VA1912wb

              I must be an idiot..I can't find the datasheet for the pin-outs. The chip has an A with a long right leg with a circle going around it from the short left leg. (Mfg?) Then it says P605 and underneath that BD6E1P. I do think these are transistors as you said KS. I think they control voltage to the transformers maybe. Anyway. Will keep searching.
              Thanks for the input. I am steady learning new things about these inverters even if i don't get it repaired. That is invaluable.

              Comment

              • elbtax
                Senior Member
                • Apr 2008
                • 59

                #8
                Re: Viewsonic lcd VA1912wb

                I have been searching on this inverter board and can find nothing. It is a Delta board,A190E2, DAC-12M030A, Rev1F. Have found 12M030 - disc & 12M030B Rev 0F. This must be a newer type inverter..

                Comment

                • tiggerific
                  Member
                  • Apr 2008
                  • 21

                  #9
                  Re: Viewsonic lcd VA1912wb

                  Believe I found them - P605 => http://pdf1.alldatasheet.com/datashe...D/AOP605L.html

                  CE mode mosfets (1xN & 1xP) in each package so it's quite possible they have gone bad.

                  Comment

                  • elbtax
                    Senior Member
                    • Apr 2008
                    • 59

                    #10
                    Re: Viewsonic lcd VA1912wb

                    Thanks Tiggerific,
                    Had to take a break for awhile. Went fishing. Caught some nice bass & bream.
                    I had pulled up the P605 but didn't get to the right one. This datasheet looks just like the chips. Thanks again. BTW, i found some more bad joints with my magnifier. Wouldn't cut off with the switch before. Will now. I think progress is being made.
                    Thanks again....

                    Comment

                    • elbtax
                      Senior Member
                      • Apr 2008
                      • 59

                      #11
                      Re: Viewsonic lcd VA1912wb

                      checked the pin-outs on the chips and found no shorts. (IF i did the test correctly.) There is a fuse ,5a,250v, in front of the small cap near the chips., F200, but it checks o.k. On the board there is a notation to replace with correct fuse type and rating. (F101). Is this the type fuse are is there another fuse somewhere? Went over the board with magnifier and can't find another fuse...Looked for a pico fuse & found nothing. I know i am not getting power to the x-formers. Any more suggestions?

                      Comment

                      • Krankshaft
                        Badcaps Legend
                        • Jan 2007
                        • 2328
                        • USA

                        #12
                        Re: Viewsonic lcd VA1912wb

                        The other fuse is right behind the IEC line cord connector in that round package.

                        The first time I saw these fuses they were in crappy Delta (go figure) Xbox power supplies.

                        Most companies use glass or ceramic fuses with axial leads soldered to them.

                        But Delta seems to prefer these fuses.
                        Last edited by Krankshaft; 05-28-2008, 09:24 AM.
                        Elements of the past and the future combining to make something not quite as good as either.

                        Comment

                        • elbtax
                          Senior Member
                          • Apr 2008
                          • 59

                          #13
                          Re: Viewsonic lcd VA1912wb

                          Thanks KS - Haven't been on the site lately. Just got my internet back. Bad storm on Wed knocked out everthing. Killed my wireless modem also. The F200 fuse is of the glass type with axial leads. It checks o.k.

                          Comment

                          • elbtax
                            Senior Member
                            • Apr 2008
                            • 59

                            #14
                            Re: Viewsonic lcd VA1912wb

                            Found it.. Checks out ok. I think i will go ahead and replace the two fuses anyway. Got nothing to lose but time & a little money. I am retired and it gives me something to do. Thanks for everyones time and advice.

                            Comment

                            • elbtax
                              Senior Member
                              • Apr 2008
                              • 59

                              #15
                              Re: Viewsonic lcd VA1912wb

                              After extensive research and testing - two of the dip switches are toast...These are the AOP605 chips. Checked with Mouser. No comparable chip. Does anyone know where i can get these chips besides HK, China, or Taiwan? Maybe Fairfield? Will keep checking. Thanks for all of your input.

                              Comment

                              • truename
                                New Member
                                • Feb 2008
                                • 6

                                #16
                                Re: Viewsonic lcd VA1912wb

                                elbtax, what dip switches are you referring to? Where are they at on the board?

                                Comment

                                • elbtax
                                  Senior Member
                                  • Apr 2008
                                  • 59

                                  #17
                                  Re: Viewsonic lcd VA1912wb

                                  The ones that are in the "dark" area of the board that is in posting #2. They are the dips that give power to the x-formers. They are actuall mosfets. Alpha Omega P605 w/N&P channels.

                                  Comment

                                  • elbtax
                                    Senior Member
                                    • Apr 2008
                                    • 59

                                    #18
                                    Re: Viewsonic lcd VA1912wb

                                    UPDATE: After searching Digi-Key, Mouser, Fairchild, etc. on the web, i finally found the mosfets at Blue Star International at $6.99 each. Not cheap. Ordered and will be here soon. Coming from Huntington, N.Y.

                                    Comment

                                    • dan8139
                                      Senior Member
                                      • Jul 2004
                                      • 57

                                      #19
                                      Re: Viewsonic lcd VA1912wb

                                      Good Luck!

                                      Comment

                                      • sonicdrive
                                        New Member
                                        • Nov 2008
                                        • 1

                                        #20
                                        Re: Viewsonic lcd VA1912wb

                                        any luck on this repair ?? i have the same problem

                                        Comment

                                        Related Topics

                                        Collapse

                                        • lostone
                                          Looking for help with a Viewsonic VP230mb where the backlight comes on only momentarily
                                          by lostone
                                          Hello, I came here after finding some similar questions asked on other monitors and hope someone here can help me get an ancient Viewsonic VP230mp (23" 4:3 LCD) back to working condition.

                                          First a little background, I have a background in computer and electrical engineering, and I'm smart enough to know I know nothing about LCD displays and how they work. For this topic I'm as green as they come.
                                          When the display is turned on the viewsonic logo displays in the uppper left for 2 seconds then the screen goes black, the power LED is green (on) and when a computer is connected...
                                          05-19-2024, 11:40 AM
                                        • jm1234
                                          Solder joints on heat sinks matter?
                                          by jm1234
                                          Hi,
                                          solder joints on heat sinks - how much do they matter? Could poor joints on heat sink cause issues if they are not properly joining to hot ground?
                                          I'm looking at power source module of Panasonic plasma TV and I see many of these having visually poor quality, but could they matter? In general I would guess no, but I saw a video where someone was stressing out the importance of tightening the screws when fastening the power source board specifically for the ground to be connected properly.
                                          Thanks
                                          04-28-2024, 04:38 AM
                                        • StefanNg
                                          Viewsonic VX2718-PC-mhd SG2701B01-8
                                          by StefanNg
                                          Hi, Badcaps.

                                          I am troubleshooting a monitor
                                          Viewsonic VX2718-PC-mhd.
                                          Panel model SG2701BSG2701-8
                                          Symptoms is no image.

                                          This panel has 2 panel board connected by a U-ribbon.
                                          When I disconnected the ribbon, I get a perfect half screen image.
                                          I took some test point voltage, when ribbon disconnected.
                                          HVAA 8.38v
                                          FVDD12 1.21v
                                          FDD33 3.3v
                                          VIN 11.79v
                                          VAA 16.85v
                                          VGHF 30.16v
                                          VGL -8.02v
                                          CK1_I ~ CK8_I 1.403v
                                          CK1_L ~ CK8_L 8.26v

                                          When I connect both panel board
                                          HVAA, VGHF, and CKx_L...
                                          05-17-2025, 01:43 AM
                                        • Fagauthier
                                          Viewsonic power supply model #EADP-64BF B Need circuit diagram…
                                          by Fagauthier
                                          I have à defective Viewsonic monitor. I can't find a circuit diagram for it' power supply.
                                          Model #EADP-64BF B
                                          The user manual have all diagram except for the power supply. I would appreciate help to find the circuit diagram, thanks...
                                          07-08-2023, 08:02 PM
                                        • soralz
                                          Viewsonic VA1912wb-4 after replace cap still not working
                                          by soralz
                                          Hi guys, I am having a problem with my Viewsonic VA1912wb monitor. It can turn on and got image (can see it thru using flashlight), but the inverter was out. At first I thought was capacitor problem. And I found out 4 of the capacitors are leaked and bulged. Then I replaced all at the outputs area but after trying again the same symptom still occurs. The only capacitors I didn't replace is the big one and the 2 small ones in the middle, rated at 22uF 50v and 47uF 50v respectively. If I change those 2 will it assure the inverter will work again? If this fails I don't plan to invest anymore on it....
                                          03-28-2018, 10:20 AM
                                        • Loading...
                                        • No more items.
                                        Working...