Sanyo DP42840 Cycles on and off

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • shadetreetrader11
    Badcaps Veteran
    • Oct 2015
    • 230
    • USA
    #1

    Sanyo DP42840 Cycles on and off

    I have a Sanyo dp42840 that cycles on and off over and over again. The backlight never gets a chance to come on.
    main board is n7ae
    I measured voltages on psb

    PS ON = 4.98
    5v = 5.02
    12v = 11.81
    24v = 24.05











    Attached Files
    Tags: None
    • shadetreetrader11
      Badcaps Veteran
      • Oct 2015
      • 230
      • USA
      #2
      Re: Sanyo DP42840 Cycles on and off

      Any help would be great

        Comment

        • maxvalutech
          Badcaps Veteran
          • Dec 2014
          • 804
          • australia
          #3
          Re: Sanyo DP42840 Cycles on and off

          Do a search for your TV make and model in threads - there is at least one with similar issue.

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA
              #4
              Re: Sanyo DP42840 Cycles on and off

              Originally posted by shadetreetrader11
              I have a Sanyo dp42840 that cycles on and off over and over again. The backlight never gets a chance to come on.
              main board is n7ae
              I measured voltages on psb

              PS ON = 4.98
              5v = 5.02
              12v = 11.81
              24v = 24.05
              So all those Voltages stay at the same values but the TV is cycling ON and OFF?
              Never stop learning
              Basic LCD TV and Monitor troubleshooting guides.
              http://www.badcaps.net/forum/showthr...956#post305956

              Voltage Regulator (LDO) testing:
              http://www.badcaps.net/forum/showthr...999#post300999

              Inverter testing using old CFL:
              http://www.badcaps.net/forum/showthr...er+testing+cfl

              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
              http://s807.photobucket.com/user/budm/library/

              TV Factory reset codes listing:
              http://www.badcaps.net/forum/showthread.php?t=24809

                Comment

                • shadetreetrader11
                  Badcaps Veteran
                  • Oct 2015
                  • 230
                  • USA
                  #5
                  Re: Sanyo DP42840 Cycles on and off

                  No, the voltages cycle on and off with the click of the power supply. The only voltage that never changes is the best 5vsb.

                    Comment

                    • shadetreetrader11
                      Badcaps Veteran
                      • Oct 2015
                      • 230
                      • USA
                      #6
                      Re: Sanyo DP42840 Cycles on and off

                      I'm at work at the moment so this is just from memory. But I did check the pins 48 and I think it was pin 23 of the IC on the main board and they both have 5 v on v them. Fail safe circuit.

                        Comment

                        • shadetreetrader11
                          Badcaps Veteran
                          • Oct 2015
                          • 230
                          • USA
                          #7
                          Re: Sanyo DP42840 Cycles on and off

                          Any advice on how to check the backlights?

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA
                              #8
                              Re: Sanyo DP42840 Cycles on and off

                              Disconnect the cable to the inverter board to see what happen.
                              Since the PS-ON is generated by the main board, then the main board some how is not sending steady ON command so the power supply is just going on and off due to ps-on cycling.
                              Never stop learning
                              Basic LCD TV and Monitor troubleshooting guides.
                              http://www.badcaps.net/forum/showthr...956#post305956

                              Voltage Regulator (LDO) testing:
                              http://www.badcaps.net/forum/showthr...999#post300999

                              Inverter testing using old CFL:
                              http://www.badcaps.net/forum/showthr...er+testing+cfl

                              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                              http://s807.photobucket.com/user/budm/library/

                              TV Factory reset codes listing:
                              http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment

                                • shadetreetrader11
                                  Badcaps Veteran
                                  • Oct 2015
                                  • 230
                                  • USA
                                  #9
                                  Re: Sanyo DP42840 Cycles on and off

                                  Thanks BudM. I just unplugged the cable running to the inverter board and there is no change.

                                    Comment

                                    • Hawkpar
                                      New Member
                                      • Oct 2017
                                      • 4
                                      • United States
                                      #10
                                      Re: Sanyo DP42840 Cycles on and off

                                      My friend has a Sanyo DP42840. Turn it on and I get the green LED for a few seconds and it cuts off. I checked the power fail lines and it is not detecting a failure. I don't have prints. No backlight. However, when I remove connector K8L and turn it on, I get backlight, but the unit still shuts off after a few seconds. Any ideas or suggestions?

                                        Comment

                                        • Hawkpar
                                          New Member
                                          • Oct 2017
                                          • 4
                                          • United States
                                          #11
                                          Re: Sanyo DP42840 Cycles on and off

                                          K8L from the main Board.

                                            Comment

                                            Previous template Next

                                            Related Topics

                                            Collapse
                                            • edugimeno
                                              (old) LG 32lk330 cycles Backlight 3 times and then OFF
                                              by edugimeno
                                              Hi!! I have been given this old TV set.
                                              When I hit the power button, the BL (as you know this is a CFL backlight) turns on, video works fine as I can see the LG logo show off, but the backlight starts going on-off for 3 times, when it gives up and turns completly off
                                              This set has a inverter board on the top right corner. This inverter (or the tubes, I don't really know) buzzes very loudly during the second that the BL stays ON. I have posted a video, turn your volume UP!

                                              https://fileport.io/9EdfmD5qtEaw

                                              I have checked voltages at the PS
                                              All normal voltages...
                                              2 Photos
                                              12-11-2023, 01:28 PM
                                            • cj_reha
                                              Mystery 80s Sanyo cap - perhaps polymer?
                                              by cj_reha
                                              Hey all I've been working on a 1984 Sanyo 27" color TV which had a smattering of bad caps in the video switching circuit. I found this oddball little 1uF 25V cap which looks to me like an early polymer, but I can't find concrete info proving it. I know Sanyo was a big player in early polymer cap development and this is the time period where they were just getting on the market, so I'm wondering if anyone has crusty old datasheets that could help identify it and determine if my suspicions are right? It has the same epoxy end seal and font/formatting as some old stock Os-Cons I've got laying...
                                              01-06-2023, 09:24 AM
                                            • angeloavv
                                              ASRock H81M-DG4 power cycles and glitches - sometimes POSTs sometimes not
                                              by angeloavv
                                              Hello everyone! This is my first post and this motherboard is driving me crazy because everything looks so non-trivial that I don't know where to start investigating. During these days I believe I watched half of the YouTube videos trying to understand how to troubleshoot power cycles but at the same time, I'm confused because my motherboard doesn't always do that and sometimes completes the POST for a few seconds: the right amount of time to freeze, show glitches on the screen, and then reset itself.

                                              Let me give you a bit more context to understand why and how we got here.
                                              ...
                                              12-26-2023, 03:32 PM
                                            • flusher
                                              Apple MBP16" A2141 820-01700 PMIC power cycles no boot no shorts
                                              by flusher
                                              Bought myself a project thing. Apple MBP16" A2141 820-01700
                                              No shorts, no visible waterdamage.
                                              Dead. no history.
                                              All USBC ports do 20V and charging battery.
                                              If you plug battery/charger PPBUS is 12.6v and all power rails like RTC, 3v3, 5v etc are present. U7800 PMIC all voltages are present APART from PPVCCPRIMCORE_PRIM_REG (not sure if it has to be present at this stage?! resistance is 40 Ohm). SSD 2.5, 0.9, 1.8 are present on both wings. Charger meter shows 30ma or something like this on charged battery.
                                              But what PMIC does is that it power cycles(dropping to...
                                              02-21-2025, 03:12 PM
                                            • toddw65
                                              Sanyo DP5834 - Gray Screen
                                              by toddw65
                                              Hey All,

                                              I have a Sanyo DP5834 that did have an issue with the backlights, but I disassembled the unit and repaired the LED strips by resoldering all of the connectors. Now I've reassembled it and I have backlights and sound, but a grayish screen. I can tap on the screen and see that it's on, but no picture. All voltages seem to be correct on the power board.

                                              Based on the LCD Flat panel TV troubleshooting guide by Bud Martin, I'm thinking the T-Con has failed because I'm getting 12v both into and out of FP1 on the T-Con. Am I on the right track?

                                              Thanks,...
                                              5 Photos
                                              10-31-2024, 10:37 AM
                                            • Loading...
                                            • No more items.
                                            Working...