Announcement

Collapse
No announcement yet.

Need help with my 900G

Collapse
X
Collapse
 
  • Page of 3
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 3 template Next
    #1

    Need help with my 900G

    I am having the same headache, many of you have had, with this monitor that was given to me about a year ago. When I first received the monitor it was DOA. So I opened it up and found several bad caps and replaced them. Put it back together and viola I had a beautiful 19 LCD monitor.

    Then after about a year of enjoyment it starts taking longer and longer amounts of time to exit out of sleep mode until eventually it wouldn't even display a power light. So for about 3 weeks now I have been hunting for info online, using my old CRT standby, and stumbled onto this site.

    Lots of great info thank you.

    I read the post about the 25x47 cap and changed it to a 25x100 and I am now getting a power light. The only problem is that it takes about 2 minutes after plugging it in for the light to come on. During that 2 minutes I can hear what sounds like the lamps quietly filling up with water. Then they go quiet as though they are full. Shortly after they go quiet the power light comes on but no lamp light.

    Just a little more history before I lost the power light, during the time it was slow coming out of sleep mode it didn't flicker at all and when it did power back on it was a bright and clear screen.

    Does anybody have any idea what I am dealing with. I'm just an electronics hobbyist and flying by the seat of my pants getting a lot of rug burn. LOLL
    Tags: None
    #2
    Re: Need help with my 900G

    Can't help with the rug burn, but let's see what we can do about the monitor! Post some pics of each board (top/bottom). Other information that will be helpful are the make of this monitor (Gateway?), along with which caps you've replaced and with what (brand/series). Do you have test equipment to help troubleshoot?

    Comment

      #3
      Re: Need help with my 900G

      Originally posted by oldmanjohnson View Post
      So I opened it up and found several bad caps and replaced them. Put it back together and viola I had a beautiful 19 LCD monitor.
      If you only replaced the obviously bad ones, then original ones that were left could be crapping out due to high ESR (ohms) or out of spec capacitance.

      What brand did you use for the replacements?

      PS. Keep your posts to one thread only. Asking the same question under multiple threads is confusing to keep track off.
      Last edited by retiredcaps; 10-24-2010, 08:09 PM. Reason: edit: One thread only please
      --- begin sig file ---

      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

        #4
        Re: Need help with my 900G

        It's a Gateway 900G.
        I replaced all but the 25x47 and then the 25x47 with a 25x100 today.
        2 have an M inside a square.(25x220 and 25x470)
        2 are Marcon (25x220)
        2 are CZ (25x470)
        1 is a YEC (35x470)
        2 are SAMXON (25x470 and 25x220)
        1 is an A inside a rectangle (25x100)
        Yes I have some test equipment.
        Attached Files

        Comment

          #5
          Re: Need help with my 900G

          M inside a square is a Panasonic ("M" for Matsushita, the old parent company), but a series would be helpful as well (FC or FM are commonly used in SMPS as recommended here at badcaps). The others are lesser known (outside of the Samxon of course), but without the series we won't be able to tell if they are appropriate. Once we get past identifying the caps I'm sure someone will ask for specific measurements.

          Comment

            #6
            Re: Need help with my 900G

            Originally posted by oldmanjohnson View Post
            I read the post about the 25x47 cap and changed it to a 25x100 and I am now getting a power light. The only problem is that it takes about 2 minutes after plugging it in for the light to come on. During that 2 minutes I can hear what sounds like the lamps quietly filling up with water. Then they go quiet as though they are full. Shortly after they go quiet the power light comes on but no lamp light.

            Just a little more history before I lost the power light, during the time it was slow coming out of sleep mode it didn't flicker at all and when it did power back on it was a bright and clear screen.
            Some comments in no particular order.

            1) In the lower left hand corner, the connectors look like they are marked with GND, and voltages. I can't make out the voltages, but I'm guessing they are the standard 5V DC, ON/OFF, and possibly 12V DC.

            With a multimeter, list, measure, report, and verify that all the voltages matches the legend on the connectors.

            One of these voltages could be out of specification.

            2) It is possible that your replacement caps 1 year ago are bad even though they show no visible distress. They can have high ESR (ohms). If I understand it correctly, when the caps warm up, the ESR drops and the monitor starts working.

            The only way to test the ESR of a cap is to use an ESR meter. These are expensive, $65+, so for the hobbyist, it is cheaper to replace the caps with low ESR caps like Panasonic FM, FC or Rubycon MCZ.

            I don't recognize many of your replacement caps and have no idea if they are low ESR caps.

            3) PCBONEZ in post #7 at

            https://www.badcaps.net/forum/showthread.php?t=11656

            goes in great detail explaining ESR, uF, ripple, etc and how each affects the circuit.
            --- begin sig file ---

            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

              #7
              Re: Need help with my 900G

              Okay I changed the caps that I changed a year ago and something good happened. I lost the slow power on light problem I had and now I get an instant power light on and off.
              I checked the power and I'm getting a steady 12v and a steady 4.92 on the 5v line.
              I am not getting any screen though. I let it run with the power light on for about 1/2 hour and nothing.
              Regarding the series of the caps I'm not sure what you mean by that. They are all 105 degree caps if that helps. With the exception of the one 35x470 that one is an 85 degree.
              Lastly I do apologize for posting my question twice yesterday. I wasn't sure where to start a new post and thought my reply to the one at the very end would take a long time to get a response.

              Comment

                #8
                Re: Need help with my 900G

                Originally posted by oldmanjohnson View Post
                Okay I changed the caps that I changed a year ago and something good happened. I lost the slow power on light problem I had and now I get an instant power light on and off.
                What did you use for replacement caps?

                I am not getting any screen though.
                If you shine a flashlight on the LCD, can you see a display?

                Regarding the series of the caps I'm not sure what you mean by that.
                Honda makes an Accord. However, there are many Accord models. It could be E, EX, SX, etc.

                Panasonic makes capacitors. They have a FM series. They have a FC series. Each series has a datasheet that lists ripple, ESR, temp, etc ratings.

                Each series is meant for different applications.
                --- begin sig file ---

                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

                  #9
                  Re: Need help with my 900G

                  The caps are Panasonic and the series are FC.
                  If I shine a flashlight on the screen I can't see anything.

                  Comment

                    #10
                    Re: Need help with my 900G

                    Originally posted by oldmanjohnson View Post
                    The caps are Panasonic and the series are FC.
                    Okay, those are good quality caps.
                    Last edited by retiredcaps; 10-25-2010, 05:58 PM. Reason: edit: Post #11 makes more sense than what I wrote.
                    --- begin sig file ---

                    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

                      #11
                      Re: Need help with my 900G

                      If you can't see an image.. check all connections to make sure everything is snug.. especially the connector at the back of the LCD panel. Also check connnections at the logic board ( this is where the VGA cable is attached to)

                      After doing that and you still have no image.. well could be one of 3 things.

                      Something has gone wrong with the circuit board that is attached to the LCD panel or you could have bad capacitors on the logic board. Also the video processing chip on the logic board may have said goodnight.

                      Caps are easy to fix.. bad logic chips pretty well mean a death sentence.

                      If that is the case.. try not to fret about it.. sooner or later this happens to all of us repairing LCD's.

                      www.bcrelectronics.ca

                      Comment

                        #12
                        Re: Need help with my 900G

                        Welcome to the forum! The 12V normally supplies the inverter assembly and the 5V supplies the the logic/video card and LCD panel. Since you're getting no backlighting or image, it can be caused by several possible problems:

                        1) At the 5V and 12V outputs, check to see if there are any blown fuses on the top of the board, or surface mount fuses on the bottom of of the power board.

                        2) Possible short of mosfets used to generate the sine wave used by the inverter transformer(s).

                        3) Bad inverter transformer or CCFL controller chip.

                        4) Bad voltage regulator on logic board. It looks like you have 2 regulators on your logic card. I believe they are the two square 3-legged devices above the two black caps at the top of the board.

                        5) Also check for fuses on the logic card.

                        6) With power off, reseat connectors between power and logic boards.
                        Last edited by jetadm123; 10-25-2010, 08:07 PM.

                        Comment

                          #13
                          Re: Need help with my 900G

                          Thank you for your response I do appreciate all the input.
                          Would it be possible for you to send me pics of where these items are located since my electronic knowledge is limited?
                          You could use the pics I posted and just put arrows on them and post them back for not just me but for all those with the same limited knowledge.
                          Thanks in advance.

                          Comment

                            #14
                            Re: Need help with my 900G

                            Voltage regulators are black, with 3 legs...

                            Comment

                              #15
                              Re: Need help with my 900G

                              Originally posted by oldmanjohnson View Post
                              Thank you for your response I do appreciate all the input.
                              Would it be possible for you to send me pics of where these items are located since my electronic knowledge is limited?
                              You could use the pics I posted and just put arrows on them and post them back for not just me but for all those with the same limited knowledge.
                              Thanks in advance.
                              Here you are. There appear to be only two of them I've circled them in yellow. I've also circled two of the mounting holes in black. Use the metal around them for the ground lead.

                              Standard orientation on these is with the large mounting tab up, the three legs down, and the legs numbered from left to right (the tab at the top is usually connected to the 2 (middle) leg). Also, indicate the complete part number of the regulators. The voltage is usually included in the part number.

                              PlainBill
                              Attached Files
                              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

                                #16
                                Re: Need help with my 900G

                                2) Possible short of mosfets used to generate the sine wave used by the inverter transformer(s).

                                3) Bad inverter transformer or CCFL controller chip.

                                Not sure where to find these items.
                                Could you send me the board identifier numbers and I will track them down.

                                Comment

                                  #17
                                  Re: Need help with my 900G

                                  red circle-mosfets

                                  yellow circle-ccfl controller
                                  Attached Files

                                  Comment

                                    #18
                                    Re: Need help with my 900G

                                    Thank you for that good info.
                                    Okay this is the most recent thing I've done, several weeks back, before I found this site, I ordered a replacement main board. I put it in and the monitor was doing the same thing. So I took it back out and put it on the shelf. Then after Solder Boy mentioned it could be a bad main board, and after I did all the things you all told me, I put it back in. It did something new because now when I plug in the monitor I still get an instant power light. Can turn it off and on at will. But now when I turn it on I get a green light for about 20 seconds and then it switches to a yellow light. But still no screen.
                                    Since I don't know how to test the mosfets and ccfl chips should I just order them? If so can I get them from Digikey and do you have a part number recommendation?
                                    Thanks in advance.

                                    Comment

                                      #19
                                      Re: Need help with my 900G

                                      Okay I have more new activity.
                                      I decided to hook the monitor up to my computer since it was acting more like it used to with the power light.
                                      When I connect it to my PC and turn it on the light stays blue, sorry not green, and when I put a flashlight next to the screen I can see a rectangular screen saver running with some test on it that I can't read.
                                      What is this telling me.
                                      I'm so close to getting this thing running I'm about to wet myself. LOL

                                      Comment

                                        #20
                                        Re: Need help with my 900G

                                        Were you ever able to identify any fuses on the logic card as jetadm123 suggested? I can't definitively see any, but check the two circled ones in the attached photo (the reference designators should begin with F.. the one on the right is either FB11 or F811).
                                        Attached Files

                                        Comment

                                        Previous 1 2 3 template Next
                                        Working...
                                        X