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    #1

    Troubleshooting Viewsonic vx2235wm

    I'm searching for a fix for a Viewsonic vx2235wm monitor and found this site almost immediately. Over the past weekend, the power at my work went out and my boss' monitor stopped working. I'll give the symptoms that I've noticed and hope to get tips on further troubleshooting or repairs. All my testing was done using the VGA connector, not DVI.

    When you power on the monitor, the blue light flickers for 1-2 seconds and then goes dark. If the monitor is left powered on but NOT connected to the PC video, the message for "No Video Signal" will appear after 10-15 minutes and the power light will come on in the orange power-save mode.

    One time last night I powered the monitor on (same blue light flicker for a couple seconds) and I left the PC Video connected. After about 20-30 minutes the PC video suddenly appeared on the monitor. I used the monitor for several hours with no problems. At one point I powered it off and back on, it came right back up. However, I turned it off for the night and It exhibited the same flickering blue light then dark symptoms in the morning. I haven't had time for further testing yet.

    Any ideas on what the problem is or further tests I should do? If I can get it working, I get to keep the monitor . Thanks.
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    #2
    Re: Troubleshooting Viewsonic vx2235wm

    Bad caps in the power supply.
    Replace ALL them except for the large filter cap (unless it shows signs of distress) and it'll be fine - but stop using it before you destroy something else.

    Comment

      #3
      Re: Troubleshooting Viewsonic vx2235wm

      Like seanc says above, this sounds like bad caps. As the caps warm up, their ESR (ohms) drops and allows the lcd to come on.
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        #4
        Re: Troubleshooting Viewsonic vx2235wm

        WEll you guys were right. I managed to get the case open and discovered a leaking cap and several bulging caps (pictured below). They are all CapXon KF series, with the exception of the one I've labeled "A", which appears to be a GL series. Since this is my first time doing a cap replacement, any suggestions on a replacement brand/series for these? Does the series matter? Any help would be appreciated.
        Attached Files
        Last edited by Kostamojen; 06-16-2011, 09:45 PM. Reason: clarification

        Comment

          #5
          Re: Troubleshooting Viewsonic vx2235wm

          Originally posted by Kostamojen View Post
          WEll you guys were right. I managed to get the case open and discovered a leaking cap and several bulging caps (pictured below). They are all CapXon KF series, with the exception of the one I've labeled "A", which appears to be a GL series. Since this is my first time doing a cap replacement, any suggestions on a replacement brand/series for these? Does the series matter? Any help would be appreciated.
          Personally, I prefer Panasonic FM or FC series caps. Other name brands have equally good series. The thread 'Which caps should I buy' in the FAQ will give you information on those.

          If you are in the US, Digi-Key is a good vendor, particularly for a small order like this. A full set of caps will cost about $10.00, including shipping. If you live in another country, another thread in the FAQ might help you - 'Where can I buy Caps?"

          Instructions on selecting caps are in this post. Pay particular attention to dimensions. It's inconvenient if you can't get the cover on because a cap is too high. And do replace all the electrolytic caps (except the 100 uF, 450 volt one). Some of the smaller ones can fail without any external sign.

          PlainBill
          Last edited by PlainBill; 06-16-2011, 09:59 PM.
          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

            #6
            Re: Troubleshooting Viewsonic vx2235wm

            That's interesting - the audio port is on the power supply board.

            Comment

              #7
              Re: Troubleshooting Viewsonic vx2235wm

              Originally posted by seanc View Post
              That's interesting - the audio port is on the power supply board.
              That is common. After all, we aren't dealing with a Marantz amplifier and JBL acoustic suspension speakers here.

              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

                #8
                Re: Troubleshooting Viewsonic vx2235wm

                I've just never seen it there before. I've seen the silkscreen, but no port.

                Comment

                  #9
                  Re: Troubleshooting Viewsonic vx2235wm

                  I've been using the Digikey website to build my order, and I've run into a little snag.

                  I need 3x 1000uf 25v caps with max dimensions of 10mm(w) / 20mm(h) but can't find it in the FM or FC series on the Digikey website. Digikey carries Panasonic caps that fit these dimensions in the M, FR, or NHG series. Any problems with going with one of those series for this cap? Recommendations? Thanks again.

                  Comment

                    #10
                    Re: Troubleshooting Viewsonic vx2235wm

                    Originally posted by Kostamojen View Post
                    I've been using the Digikey website to build my order, and I've run into a little snag.

                    I need 3x 1000uf 25v caps with max dimensions of 10mm(w) / 20mm(h) but can't find it in the FM or FC series on the Digikey website. Digikey carries Panasonic caps that fit these dimensions in the M, FR, or NHG series. Any problems with going with one of those series for this cap? Recommendations? Thanks again.
                    The Panasonic FR series will work fine.

                    Comment

                      #11
                      Re: Troubleshooting Viewsonic vx2235wm

                      Hey guys, still waiting for my replacement caps to come in. But, I was inspecting the back of my circuit board and had a concern. With some of the cap soldering points, it looks like there is only a millimeter, or so, of space to the adjacent circuits on the board. I've never done precision soldering, so I was wondering if there is a good way to protect the adjacent circuits, while soldering the new caps. Any tips would be helpful. Thanks.

                      Comment

                        #12
                        Re: Troubleshooting Viewsonic vx2235wm

                        Looking at the caps you have to replace I don't think it is that bad. Just lean the solder tip away from other components. If you have a solder gun with a huge tip, that might be a problem, but a normal tip should give you plenty of space between components.
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                        If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                        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.

                        Please do not post inline and offsite as they slow down the loading of pages.

                        --- end sig file ---

                        Comment

                          #13
                          Re: Troubleshooting Viewsonic vx2235wm

                          Kostamojen, in addition to using a fine tip as retiredcaps mentioned, practice your soldering skills on some junk piece of electronics if in doubt.

                          While I've never tried doing it, in theory you could lay down some teflon tape, or any heat resistant material with a little hole that exposes the solder joint, but I suspect it would be more trouble than it's worth. If you have shaky hands, support your wrist with a book or something same height or a little taller than the PCB while soldering.

                          Comment

                            #14
                            Re: Troubleshooting Viewsonic vx2235wm

                            Hey guys. Well got my caps in and did the surgery. Think I did a decent job with the soldering, but I'm getting no power-on lights or picture. What should I test next? Thanks.

                            Comment

                              #15
                              Re: Troubleshooting Viewsonic vx2235wm

                              Considering that the monitor at least powered on before but not after the recap, a few things come to mind...
                              First make sure you didn't create a solder bridge over anything. Also check if there are solder blobs shorting something.
                              The second thing that comes to mind - did you plug in all of the connectors properly and securely? Did you check for loose screws and other things that could possible short a nearby circuit.
                              Also, did you place the new caps in the right way, observing the polarity on the board and on the caps?
                              Last but not least, if you have a multimeter, check that the power supply is outputting the proper voltages. They should be labeled on one of the low-voltage connectors.

                              Comment

                                #16
                                Re: Troubleshooting Viewsonic vx2235wm

                                In addition to momaka's comments, it might be helpful if you post some photos of your handiwork. Maybe someone will see something you missed. Post some good focused pics of the top and bottom of your board.

                                Comment

                                  #17
                                  Re: Troubleshooting Viewsonic vx2235wm

                                  Originally posted by momaka View Post
                                  Considering that the monitor at least powered on before but not after the recap, a few things come to mind...
                                  First make sure you didn't create a solder bridge over anything. Also check if there are solder blobs shorting something.
                                  The second thing that comes to mind - did you plug in all of the connectors properly and securely? Did you check for loose screws and other things that could possible short a nearby circuit.
                                  Also, did you place the new caps in the right way, observing the polarity on the board and on the caps?
                                  Last but not least, if you have a multimeter, check that the power supply is outputting the proper voltages. They should be labeled on one of the low-voltage connectors.
                                  1) I did create a solder bridge at one point while connecting the new caps, but I corrected the problem before the monitor was tested. And I don't think there are any solder blobs, but I'll check again.

                                  2)All connectors were securely connected and double checked. No screws that appear to be shorting anything.

                                  3) I was VERY careful to observe polarity on the board. I created a schematic before removing the old caps, and followed it carefully. Even double checked everything before the test.

                                  4) I'm going to borrow a multimeter and check the voltages next.

                                  Comment

                                    #18
                                    Re: Troubleshooting Viewsonic vx2235wm

                                    I've uploaded some pictures so you can check my solder work. Let me know if you see anything questionable.

                                    I've borrowed a multimeter, but, to be honest I don't really know what I'm doing here. I'd appreciate an explaination of the process of testing the voltages.

                                    Should the board be connected to the rest of the monitor components when I test the voltages? What setting do I use on the multimeter? Which lead (black/red) do I touch where?

                                    Sorry for being such a noob. I'm very interested in learning how to do this, and you're help is much appreciated. Thanks again.
                                    Attached Files

                                    Comment

                                      #19
                                      Re: Troubleshooting Viewsonic vx2235wm

                                      Originally posted by Kostamojen View Post
                                      1) I did create a solder bridge at one point while connecting the new caps, but I corrected the problem before the monitor was tested. And I don't think there are any solder blobs, but I'll check again.

                                      2)All connectors were securely connected and double checked. No screws that appear to be shorting anything.

                                      3) I was VERY careful to observe polarity on the board. I created a schematic before removing the old caps, and followed it carefully. Even double checked everything before the test.

                                      4) I'm going to borrow a multimeter and check the voltages next.
                                      Excellent!

                                      Originally posted by Kostamojen View Post
                                      I've borrowed a multimeter, but, to be honest I don't really know what I'm doing here. I'd appreciate an explaination of the process of testing the voltages.
                                      Well actually, before you even test the voltages, first measure resistance between the leads of the caps your soldered and see if you find any short circuits (i.e 3 ohms or less, depending on how good your multimeter is).

                                      If you don't find any shorts then you can test the voltages. But first some safety tips...

                                      See that thick black line on the top of the board where the logo "Delta" is (or alternatively that white line on the bottom of the board)? - that line differentiates between primary and secondary side. On the primary side, high-voltages will be present when the PSU is plugged in so DO NOT touch anything with your hands on that side when the PSU is plugged in. The primary side is the one where that big 400v cap is located.
                                      Also avoid getting your hands near the inverter transformers - that's those near the blue ceramic capacitors and CCFL connectors.

                                      Fortunately, the voltages you will be measuring first are located on the secondary side - i.e. the low voltage side. Whenever measuring voltages on the secondary side, the black probe of your multimeter should always be placed on ground. The screws that tie down the PSU as well as the metal body of the monitor are all ground points you can use. With the red probe, you measure whatever voltage you want to measure.

                                      Now, I would really like to tell you what voltages to measure, but for that I need to know what voltages this PSU outputs. This piece of information can usually be found on the connector that gives power to the video board. In fact, based on the first pic your posted in this thread, you can see that some of the pins on that connector are indeed labeled. Please post what those labels are.
                                      Normally most monitors will have a 5v and a 12v rail (with the 12v rail sometimes given as 13v or 15v, depending on the monitor/PSU). Occasionally, some monitors will have a standby rail too (usually 5v), but I don't think this is the case with this monitor. Therefore, the 5v and/or 12v rail should be present at all times when the monitor is plugged it.

                                      Originally posted by Kostamojen View Post
                                      Should the board be connected to the rest of the monitor components when I test the voltages?
                                      Yes.
                                      Last edited by momaka; 06-25-2011, 10:57 PM.

                                      Comment

                                        #20
                                        Re: Troubleshooting Viewsonic vx2235wm

                                        While you're measuring resistances, try measuring the resistance across the main fuse, F101? It's a small square box mounted behind the the main power plug. It should measure under 1 ohm.

                                        Comment

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