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ViewSonic VG2021m - DAC-12M033 AF

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    #21
    Re: ViewSonic VG2021m - DAC-12M033 AF

    I have a vg2021m with the following symptoms:
    For a couple of months, when switching on the monitor, it would flicker and turn off. If I keep turning on and off for a while, the monitor would finally start working again. Yesterday, it completely quit and any amount of turning on and off would not make it turn on again. I opened it up tried to power it on when opem. It looks like the 4 ccfl bulbs are lighting up for a brief moment and then it is being turned off.

    Is this problem related to the inverter or the backlight? If it's the inverter, is it usually just the caps?

    Comment


      #22
      Re: ViewSonic VG2021m - DAC-12M033 AF

      I am working on this same board. the small cap is a 50v 22uf.Can any one help me identify a cap. looks like c100 by the f200 fuse.
      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

      Comment


        #23
        Re: ViewSonic VG2021m - DAC-12M033 AF

        This PCB is also used on Acer AL2017 bmd
        DAC-12M033 AF
        Revision 02A

        Thanks for some of the cap values. The dry toothpaste was covering some of them and I couldn't get it off without peeling off the cap sleeve which would defeat the purpose. I'm going to recap with UCC LXZ or LXY or whatever is cheapest.
        "We have offered them (the Arabs) a sensible way for so many years. But no, they wanted to fight. Fine! We gave them technology, the latest, the kind even Vietnam didn't have. They had double superiority in tanks and aircraft, triple in artillery, and in air defense and anti-tank weapons they had absolute supremacy. And what? Once again they were beaten. Once again they scrammed [sic]. Once again they screamed for us to come save them. Sadat woke me up in the middle of the night twice over the phone, 'Save me!' He demanded to send Soviet troops, and immediately! No! We are not going to fight for them."

        -Leonid Brezhnev (On the Yom Kippur War)

        Comment


          #24
          Re: ViewSonic VG2021m - DAC-12M033 AF

          Just one more thing. In case someone forgot the cap values. The .00A caps listed before are not the same as the 02A revision. Here are the correct 02A values:


          C200 - 25v 220uF CAPXON KF
          CE101 - 25v 220uF CAPXON KF
          CE103 - 25V 1000uF CAPXON KF
          R100 - 25v 1000uF(Near R100. PCB marking covered with toothpaste)
          CE105 - 10v 2200uF - TAICON (unknown series)
          CE104 - 10v 1000uF - TAICON (Referenced from 00A posting. Not sure if this is correct)
          CE108 - 220uF 25v - CAPXON KF
          J100 - 50v 22uf - CAPXON GL(Starter cap near big primary. Marking covered with toothpaste)

          Primary cap is 400v 150uF but this does not need to be replaced.
          "We have offered them (the Arabs) a sensible way for so many years. But no, they wanted to fight. Fine! We gave them technology, the latest, the kind even Vietnam didn't have. They had double superiority in tanks and aircraft, triple in artillery, and in air defense and anti-tank weapons they had absolute supremacy. And what? Once again they were beaten. Once again they scrammed [sic]. Once again they screamed for us to come save them. Sadat woke me up in the middle of the night twice over the phone, 'Save me!' He demanded to send Soviet troops, and immediately! No! We are not going to fight for them."

          -Leonid Brezhnev (On the Yom Kippur War)

          Comment


            #25
            Re: ViewSonic VG2021m - DAC-12M033 AF

            Hi, do you know the value of the resistor R100

            Comment


              #26
              Re: ViewSonic VG2021m - DAC-12M033 AF

              How do you open the case? I have unscrewed the back, but now I need to pop open the case I think, but I'm afraid I might break it.

              Comment


                #27
                Re: ViewSonic VG2021m - DAC-12M033 AF

                Take off the stand first. I think there's some screws behind it. After you're done, you got to wedge the sides open.
                "We have offered them (the Arabs) a sensible way for so many years. But no, they wanted to fight. Fine! We gave them technology, the latest, the kind even Vietnam didn't have. They had double superiority in tanks and aircraft, triple in artillery, and in air defense and anti-tank weapons they had absolute supremacy. And what? Once again they were beaten. Once again they scrammed [sic]. Once again they screamed for us to come save them. Sadat woke me up in the middle of the night twice over the phone, 'Save me!' He demanded to send Soviet troops, and immediately! No! We are not going to fight for them."

                -Leonid Brezhnev (On the Yom Kippur War)

                Comment


                  #28
                  Re: ViewSonic VG2021m - DAC-12M033 AF

                  Just wanted to add my recent experience with that monitor:
                  Came to me dead,customer said smelled really badly..Opened it up(was litlle difficult ) ,and find the main fuse burned..Just to see how it behaves,I solder another one which of course burned immediately..
                  I desolder what I think is the power mosfet,a 2761I and measures OK.With it off the board pluged it up and same thing:Burned fuse right away.
                  In the end I checked the rectifier bridge.. It had one diode shorted.I replaced the bridge with for diodes and working fine since..
                  The thing is I didn't put it to much stress,just a quick on-off and now I'm wondering that: Will the 1A diodes stand the load OK?
                  What do you think?
                  P.S Well it doesn't look too good..The bridge has "FL406" on it which is 800V 4A bridge..The thing is that I didn't have any other diodes handy, so I'll order that bridge and hope the diodes stand the extra amps until replacement comes..
                  Last edited by Joun; 09-20-2011, 11:58 AM.

                  Comment


                    #29
                    Re: ViewSonic VG2021m - DAC-12M033 AF

                    Originally posted by Joun View Post
                    Just wanted to add my recent experience with that monitor:
                    Came to me dead,customer said smelled really badly..Opened it up(was litlle difficult ) ,and find the main fuse burned..Just to see how it behaves,I solder another one which of course burned immediately..
                    I desolder what I think is the power mosfet,a 2761I and measures OK.With it off the board pluged it up and same thing:Burned fuse right away.
                    In the end I checked the rectifier bridge.. It had one diode shorted.I replaced the bridge with for diodes and working fine since..
                    The thing is I didn't put it to much stress,just a quick on-off and now I'm wondering that: Will the 1A diodes stand the load OK?
                    What do you think?
                    P.S Well it doesn't look too good..The bridge has "FL406" on it which is 800V 4A bridge..The thing is that I didn't have any other diodes handy, so I'll order that bridge and hope the diodes stand the extra amps until replacement comes..
                    Stick with the 4A bridge as a 1A diode probably won't last very long.

                    Comment


                      #30
                      Re: ViewSonic VG2021m - DAC-12M033 AF

                      I agree with you; I just don't know how many of those 4amps which is bridge's maximum are drawn by the rest of the circuit..

                      Comment


                        #31
                        Re: ViewSonic VG2021m - DAC-12M033 AF

                        Just got two of these monitors from outside a dumpster. Both have 3 bad caps each. Same ones as mentioned before. I will be replacing all of the CapXon caps with the exception of the 400V unless anyone thinks the 400v should be replaced too?

                        Comment


                          #32
                          Re: ViewSonic VG2021m - DAC-12M033 AF

                          Originally posted by ecallenil View Post
                          Just got two of these monitors from outside a dumpster. Both have 3 bad caps each. Same ones as mentioned before. I will be replacing all of the CapXon caps with the exception of the 400V unless anyone thinks the 400v should be replaced too?
                          I never see monitors by a dumpster.

                          The big filter cap can be left alone. The big ones rarely but can fail. It doesn't undergo the same stress as the smaller ones. So it is your call.
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                            #33
                            Re: ViewSonic VG2021m - DAC-12M033 AF

                            Originally posted by retiredcaps View Post
                            I never see monitors by a dumpster.

                            The big filter cap can be left alone. The big ones rarely but can fail. It doesn't undergo the same stress as the smaller ones. So it is your call.
                            Yeah, this company was throwing out all kinds of stuff last week - computers, hard drives, monitors. I thought about grabbing some of the stuff but it was pretty far in the dumpster. Today it was full so they were shoving the stuff on the side.

                            Thanks for your advice on the larger cap. What are your thoughts on the 50v starter cap near J100? It looks like a really tight spot to get to given the extremely close proximity to the other components. If I have to get in there, I can. If not, I'll leave it.

                            Again, thanks for your help.

                            Comment


                              #34
                              Re: ViewSonic VG2021m - DAC-12M033 AF

                              Originally posted by ecallenil View Post
                              Yeah, this company was throwing out all kinds of stuff last week - computers, hard drives, monitors. I thought about grabbing some of the stuff but it was pretty far in the dumpster. Today it was full so they were shoving the stuff on the side.

                              Thanks for your advice on the larger cap. What are your thoughts on the 50v starter cap near J100? It looks like a really tight spot to get to given the extremely close proximity to the other components. If I have to get in there, I can. If not, I'll leave it.

                              Again, thanks for your help.
                              Replace the startup cap. Those can cause endless grief when they fail, and are inexpensive.

                              PlainBill
                              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                              Comment


                                #35
                                Re: ViewSonic VG2021m - DAC-12M033 AF

                                Originally posted by ecallenil View Post
                                Yeah, this company was throwing out all kinds of stuff last week - computers, hard drives, monitors.
                                Does your city not have electronic recycling depots?
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                                We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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                                  #36
                                  Re: ViewSonic VG2021m - DAC-12M033 AF

                                  Originally posted by retiredcaps View Post
                                  Does your city not have electronic recycling depots?
                                  Yes they do. The sad part is the recycling center is just 3 minutes down the street from where all this stuff was being thrown out. Some people just don't get it.

                                  Comment


                                    #37
                                    Re: ViewSonic VG2021m - DAC-12M033 AF

                                    2009-09-10
                                    Originally posted by lucky13 View Post
                                    OK you can leave that 400v one there.
                                    2010-10-26
                                    Originally posted by mockingbird View Post
                                    Primary cap is 400v 150uF but this does not need to be replaced.
                                    Based on my experience earlier today, maybe it would be good preventive medicine to change it too?

                                    My VG2021m was plugged into a CNB900 Conext "UPS" when shortly after I woke up this AM the power blinked several times in short succession, then went off and stayed off half an hour. During the commotion caused by the multiple interruptions, I heard some kind of unusual sound come from the LCD, which has since refused to power up.

                                    When it was about 2-3 years old its DAC-12M033AF REV01A needed resurrection via replacement of CE101, CE102, CE103, CE108 & C200. I used "matching" new very old stock Jackcons, as that's what I had and I didn't want to wait for shipping better. Of those I didn't replace, the 22uf 50V CE107 is Capxon, the 1000uf 10V C104, 2200uf 10V CE105, and 150uf 400V CE106 Taicons.

                                    On my board, none of the 8 in a new LCDalternatives kit have any visible problems. CE106 has a very slightly visible crown, and a very modest amount, maybe 3mm in largest dimension, of oozing from its plus leg. Could maybe what I heard have been from popping the yellow stuff?

                                    I'll need to place a cap order to fix it this time. Before I do, can anyone suggest if I might actually need anything except the big CE106? Regardless of that answer, besides the Capxon, would it make much sense to replace the rest with Nichicon/Panasonic/Rubycon? Is it likely it would need something other than radial caps to make it work again?

                                    PS1 - Why did mockingbird call the 22uf 50V a "starter" cap?
                                    PS2 - Why did mockingbird call the 150uf 400V "primary"?

                                    Comment


                                      #38
                                      Re: ViewSonic VG2021m - DAC-12M033 AF

                                      "PS1 - Why did mockingbird call the 22uf 50V a "starter" cap? It is the filter cap that is used for storage and filtering the Voltage that is used for starting up and running the switch mode IC. The start up cap is also in the primary side.

                                      PS2 - Why did mockingbird call the 150uf 400V "primary"? because that main filter cap is in the Primary (HOT deadly side of the circuit) which is connected to the main AC 120V. You do not want to touch anything in the primary side. The Cold side is the electrically isolated by the transformer from the primary side, the 5V, 12v, 24V circuits and the logic board are isolated from the primary side.
                                      Last edited by budm; 10-03-2013, 12:06 AM.
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
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                                      Inverter testing using old CFL:
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                                        #39
                                        Re: ViewSonic VG2021m - DAC-12M033 AF

                                        Originally posted by mrmazda View Post
                                        My VG2021m was plugged into a CNB900 Conext "UPS" when shortly after I woke up this AM the power blinked several times in short succession, then went off and stayed off half an hour. During the commotion caused by the multiple interruptions, I heard some kind of unusual sound come from the LCD, which has since refused to power up.

                                        When it was about 2-3 years old its DAC-12M033AF REV01A needed resurrection via replacement of CE101, CE102, CE103, CE108 & C200. I used "matching" new very old stock Jackcons, as that's what I had and I didn't want to wait for shipping better. Of those I didn't replace, the 22uf 50V CE107 is Capxon, the 1000uf 10V C104, 2200uf 10V CE105, and 150uf 400V CE106 Taicons.

                                        On my board, none of the 8 in a new LCDalternatives kit have any visible problems. CE106 has a very slightly visible crown, and a very modest amount, maybe 3mm in largest dimension, of oozing from its plus leg. Could maybe what I heard have been from popping the yellow stuff?

                                        I'll need to place a cap order to fix it this time. Before I do, can anyone suggest if I might actually need anything except the big CE106? Regardless of that answer, besides the Capxon, would it make much sense to replace the rest with Nichicon/Panasonic/Rubycon? Is it likely it would need something other than radial caps to make it work again?
                                        I replaced the obviously bad 150uF 400V with EPAG401ELL151MM35S, the other 8 with Nichicon as follows:

                                        UPW1H220MDD 22uF 50V
                                        UPW1E221MPD 220uF 25V
                                        UHD1A102MPD6 1000uF 10V
                                        UVY1E102MPD 1000uF 25V
                                        UPS1A222MHD 2200uF 10V

                                        All seems well now 4 hours after powering it back up. I hope it lasts. I don't like HD aspect screens for puter use. Replacing it would be hard.

                                        Comment


                                          #40
                                          Re: ViewSonic VG2021m - DAC-12M033 AF

                                          I also got this monitor for free from a colleague at work, said it is dead.

                                          Opened case and found bulging caps and something strange.

                                          Someone tried already to fix this monitor and he used Elna 85C caps as replacement caps!

                                          And to make things worse, one of the caps he used was made in late 80s or early 90s if I remember correct!

                                          I replaced every bulging cap on that board and of course the 85 Celsius caps.

                                          I used a mix of Good caps and mediocre (Teapo) caps.

                                          BTW I am fairly disappointed with this power supply and especially the fact that Delta designed it.

                                          Every secondary cap is near heatsinks that get too hot during operation.

                                          Also, the spaces between caps are almost non existent. Why put all those caps so close together when there is so much empty space on the PCB?

                                          Anyway, after recap, psu would endlessly click

                                          Checked voltages and seems it tries to power on but immediately shuts down due to protection kicking in cause 1 voltage rail is bad.

                                          Checked and found that the 15V rail is faulty. Checked and found 20A shorted rectifier, please check attached image of the rectifier removed from PCB

                                          The original rectifier was insulated type, those don't conduct heat well to the heatsink. Replaced it with 30A not insulated rectifier. Used thermal pad and cheap thermal paste and washer to insulate the screw from the heatsink.

                                          Monitor now works!

                                          Heatsink doesn't get too hot and the rectifier stays cool, so the heat transfer works flawlessly between those 2.

                                          I also put heatshrink on a stupid resistor that is generating noticeable amount of heat and is very close to secondary caps and also too close to the psu output pins and it could short one of its legs with the pins.

                                          Again, very disappointed with Delta electronics with this unit

                                          I am definitely keeping this monitor though
                                          Attached Files
                                          Last edited by goodpsusearch; 01-16-2022, 03:02 PM.

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