Announcement

Collapse
No announcement yet.

KDS K-92BW Turns off

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

    KDS K-92BW Turns off

    Hello Everyone,

    I've done a few LCD repairs in the past usually the normal capacitor repair and few times I've had to diagnose shorts in diodes etc.

    Anyhow, this time I have an 19" LCD that turns on for two/three secondsand the screen lights perfectly then turns off and the LED stays solid meaning the monitor is still detecting a signal. Turning the monitor of and on again provides the same result. Comes on for 2/3 secs then off.

    I've removed the board and all the caps look good (blue HEC 105 degree's). All the solder joints etc also look good.

    The board states Proview Electronics 200-000-1700TLBM-BH Version: B
    PI-1900TLB REV: A Date: 03, 12, 2007

    Any ideas on whats causing this? How would I test the backlights? I read somewhere that some units turn off the monitor when a backlight fails to prevent damage. If it is a bad backlight why would the screen look fine when first turned on. Wouldn't it just be dark from the get go.

    Also, I have another 19" LCD screen here that I know the back lights are good in. However, it is a different model. Can I connect it to the KDS power board with just the 4 power connectors or will I also have to connect it to the ribbion cable for testing.

    Thx for all the help.
    Tags: None
    #2
    Re: KDS K-92BW Turns off

    Just noticed the board is actually 200-000-171DTLBMH or ETL-XPC-204. A search on the net turned up a few pics but no schematics.

    Comment

      #3
      Re: KDS K-92BW Turns off

      It's most likely the backlight inverter detecting either a tube failure/excess current draw on the inverter.

      There are MANY posts/threads on here regarding these types of failures. You could have anything from bad caps on the inverter board to failing output transformers. I would check the tubes and caps first as outlined in the other threads.

      As the tubes heat up and draw more current this may be why it comes on briefly and then shuts down.

      Shining a flashlight on the screen, can you still see the picture? If yes, then you're dealing with the backlight problem. If no, you may have a failure earlier on in the circuit.

      Once you open it up, post some pics of the inverter board.

      Toast
      veritas odium parit

      Comment

        #4
        Re: KDS K-92BW Turns off

        Well I tried the flashlight thing but could not see an image. However I don't think the flashlight was bright enough as it was LED.

        Anyhow I disconnected the screen from the ribbion cable and left only the HV connections. Powered on the screen and got a white background light for a few seconds and it went dark again.

        I then took another 19" screen I had laying around out of another brand, connected it to the HV only and get the white background lights only this time is remains on.

        I assume it must be a failing CCFL as the second screens lights remain on. Just no picture obviously becuase I cannot connect it to the LCD electronics.

        What next. How to I determine when backlight to purchase. Is there a number or anything on them once removed from the unit?

        Comment

          #5
          Re: KDS K-92BW Turns off

          When you disassemble the panel (carefully!!!) and gain access to the CCFLs measure their diameter and length. Then match that.

          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

            #6
            Re: KDS K-92BW Turns off

            Originally posted by chrimeg
            I assume it must be a failing CCFL as the second screens lights remain on. Just no picture obviously becuase I cannot connect it to the LCD electronics.
            Absolutely.
            There are 10 kind of people in this world: those that understand binary, and those who don't.
            • ASUS ROG Maximus IX Code
            • Intel Core i5-7600K 3.8GHz
            • 16gb GSKILL TridentZ RGB DDR4-3200
            • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
            • Windows 10 Pro x64
            • GeForce GT1050
              2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

            Comment

              #7
              Re: KDS K-92BW Turns off

              I got the backlights out...four of them.

              They seem to be 16 inches long and really thin. Not sure how I'm going to measure the diameter.

              Anyhow, while shopping online for a match I notice alot of places need the voltage and running amps etc. How do you know these things? Will this make a difference?

              Comment

                #8
                Re: KDS K-92BW Turns off

                Well got a better measurement this morning.

                16.6 inches (419mm) by about 2mm diameter.

                Again not sure of what the voltages are such as startup and running peak, current, amps, watts. How do I find these out.

                Also where is the best place to buy these lamps. Should I replace all 4 as 3 of them look dark in the corners.

                Comment

                  #9
                  Re: KDS K-92BW Turns off

                  Originally posted by chrimeg
                  Well got a better measurement this morning.

                  16.6 inches (419mm) by about 2mm diameter.

                  Again not sure of what the voltages are such as startup and running peak, current, amps, watts. How do I find these out.

                  Also where is the best place to buy these lamps. Should I replace all 4 as 3 of them look dark in the corners.
                  For amp/voltage, sometimes it is written on the PSU/inv board. Black/dark ends are kind of normal. If you want to replace them all, go ahead, but I doubt all are failing (it could happen).
                  There are 10 kind of people in this world: those that understand binary, and those who don't.
                  • ASUS ROG Maximus IX Code
                  • Intel Core i5-7600K 3.8GHz
                  • 16gb GSKILL TridentZ RGB DDR4-3200
                  • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
                  • Windows 10 Pro x64
                  • GeForce GT1050
                    2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

                  Comment

                    #10
                    Re: KDS K-92BW Turns off

                    I believe voltage is a function of the length while current is a function of diameter.

                    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

                      #11
                      Re: KDS K-92BW Turns off

                      Hey, I'm a first time poster!

                      I have the same problem. My monitor turns off after a few seconds. However, the color is also a bit weird upon startup and takes a while to "warm up" to its normal color. Is the color a function of a capacitor, or could that also be a function of the ccfl?

                      Thanks!

                      Comment

                        #12
                        Re: KDS K-92BW Turns off

                        Originally posted by agrawalr View Post
                        Hey, I'm a first time poster!

                        I have the same problem. My monitor turns off after a few seconds. However, the color is also a bit weird upon startup and takes a while to "warm up" to its normal color. Is the color a function of a capacitor, or could that also be a function of the ccfl?

                        Thanks!
                        Is it reddish/pinkish? If so, that's a classic sign of impending lamp failure.
                        36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                        Comment

                          #13
                          Re: KDS K-92BW Turns off

                          Yeah, it is a bit reddish pinkish.

                          Do you guys have any recommendations of where to purchase these lamps from?

                          Thanks again!

                          Comment

                            #14
                            Re: KDS K-92BW Turns off

                            Originally posted by agrawalr View Post
                            Do you guys have any recommendations of where to purchase these lamps from?
                            http://ccflwarehouse.com/

                            http://www.ccfldirect.com/
                            --- 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

                              #15
                              Re: KDS K-92BW Turns off

                              perfect! thanks for the prompt replies!

                              Comment

                                #16
                                Re: KDS K-92BW Turns off

                                Originally posted by agrawalr View Post
                                Yeah, it is a bit reddish pinkish.
                                Dead lamps.
                                There are 10 kind of people in this world: those that understand binary, and those who don't.
                                • ASUS ROG Maximus IX Code
                                • Intel Core i5-7600K 3.8GHz
                                • 16gb GSKILL TridentZ RGB DDR4-3200
                                • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
                                • Windows 10 Pro x64
                                • GeForce GT1050
                                  2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

                                Comment

                                  #17
                                  Re: KDS K-92BW Turns off

                                  So, I got the lamps and installed them. The lights come on and everything looks great for 2 - 3 seconds (no more reddish hue), but the lamps still turn off after. Could it be some kind of capacitor issue? Again, thanks for the help!

                                  Comment

                                    #18
                                    Re: KDS K-92BW Turns off

                                    Originally posted by agrawalr View Post
                                    So, I got the lamps and installed them. The lights come on and everything looks great for 2 - 3 seconds (no more reddish hue), but the lamps still turn off after. Could it be some kind of capacitor issue? Again, thanks for the help!
                                    There are 10 kind of people in this world: those that understand binary, and those who don't.
                                    • ASUS ROG Maximus IX Code
                                    • Intel Core i5-7600K 3.8GHz
                                    • 16gb GSKILL TridentZ RGB DDR4-3200
                                    • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
                                    • Windows 10 Pro x64
                                    • GeForce GT1050
                                      2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

                                    Comment

                                      #19
                                      Re: KDS K-92BW Turns off

                                      any ideas which capacitor I should be looking for?

                                      Comment

                                        #20
                                        Re: KDS K-92BW Turns off

                                        Originally posted by agrawalr View Post
                                        any ideas which capacitor I should be looking for?
                                        Post a list of all the caps on your board and replacements would be suggested accordingly
                                        There are 10 kind of people in this world: those that understand binary, and those who don't.
                                        • ASUS ROG Maximus IX Code
                                        • Intel Core i5-7600K 3.8GHz
                                        • 16gb GSKILL TridentZ RGB DDR4-3200
                                        • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
                                        • Windows 10 Pro x64
                                        • GeForce GT1050
                                          2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

                                        Comment

                                        Previous 1 2 3 template Next
                                        Working...
                                        X