Hannspree T280H not turning on

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  • cschappa
    Craig
    • Sep 2023
    • 8
    • United States

    #1

    Hannspree T280H not turning on

    1st Post here guys. I have a T280H that the cat knocked over. Everything else was fine before the fall, but now there is no display. There is a yellow LED that pulsates dim to bright.

    I have taken out the power supply, R0800-0805-060.
    I tried to test the pin outs 12v, see pic, which reads 0.00
    I do have 5v.

    Also, I noticed, the 2 metal heat sinks, checking the voltage between the 2 of them reads ~60v, but I am not sure if that is normal.

    I have looked at another post, similar PS, but a little different.

    Thanks in advance for any recommended suggestions.

    Craig
    Attached Files
  • nomoresonys
    Badcaps Legend
    • Jan 2013
    • 12086
    • U.S.

    #2
    Re: Hannspree T280H not turning on

    Maybe the screen is broken, were any cables loose, look the screen over carefully with a flashlight.

    Comment

    • cschappa
      Craig
      • Sep 2023
      • 8
      • United States

      #3
      Re: Hannspree T280H not turning on

      I just checked the screen with a flashlight, it all looks the same, no cracks or bubbles. The cables all look to be intact.

      Comment

      • nomoresonys
        Badcaps Legend
        • Jan 2013
        • 12086
        • U.S.

        #4
        Re: Hannspree T280H not turning on

        Is the input set correctly, might have bumped it.

        Comment

        • nomoresonys
          Badcaps Legend
          • Jan 2013
          • 12086
          • U.S.

          #5
          Re: Hannspree T280H not turning on

          Are you testing it with everything plugged in or is that cable unhooked?

          Comment

          • cschappa
            Craig
            • Sep 2023
            • 8
            • United States

            #6
            Re: Hannspree T280H not turning on

            Testing with PS disconnected from everything, except main power.

            Comment

            • cschappa
              Craig
              • Sep 2023
              • 8
              • United States

              #7
              Re: Hannspree T280H not turning on

              Originally posted by nomoresonys
              Is the input set correctly, might have bumped it.

              When TV is powered on, the yellow light would turn blue.

              Comment

              • nomoresonys
                Badcaps Legend
                • Jan 2013
                • 12086
                • U.S.

                #8
                Re: Hannspree T280H not turning on

                Test it with everything hooked up as normal, see what you have on those same voltages you checked.

                Comment

                • nomoresonys
                  Badcaps Legend
                  • Jan 2013
                  • 12086
                  • U.S.

                  #9
                  Re: Hannspree T280H not turning on

                  Can try a simple reset, unplug tv for a few minutes then press and hold power button on tv for 30 seconds, then plug it in and try it.

                  Comment

                  • nomoresonys
                    Badcaps Legend
                    • Jan 2013
                    • 12086
                    • U.S.

                    #10
                    Re: Hannspree T280H not turning on

                    Go ahead and heat up those capacitors on your powerboard for a couple minutes with a hairdryer, then try it.

                    Comment

                    • nomoresonys
                      Badcaps Legend
                      • Jan 2013
                      • 12086
                      • U.S.

                      #11
                      Re: Hannspree T280H not turning on

                      If nothing broke and all connections are good, kinda thinking maybe a marginal capacitor gave up.

                      Comment

                      • nomoresonys
                        Badcaps Legend
                        • Jan 2013
                        • 12086
                        • U.S.

                        #12
                        Re: Hannspree T280H not turning on

                        Suppose it could have loosened a solder joint so check the joints on powerboard.

                        Comment

                        • cschappa
                          Craig
                          • Sep 2023
                          • 8
                          • United States

                          #13
                          Re: Hannspree T280H not turning on

                          So, everything is reconnected, I tried to heat the board with hair dryer, and measured leads with meter.

                          12v = 0
                          5v = 0
                          5vsb = 5.2

                          The large brown cap, 450v 120uF reads 169v and does not change when power button is pressed.

                          Comment

                          • lotas
                            Badcaps Legend
                            • Jan 2016
                            • 4474
                            • Russia

                            #14
                            Re: Hannspree T280H not turning on

                            Most likely, your power supply is only in standby mode; in order for it to go into working mode, it needs to give a command - this must be done by the motherboard (3-5V) to turn on the β€œremote” pin.

                            Comment

                            • nomoresonys
                              Badcaps Legend
                              • Jan 2013
                              • 12086
                              • U.S.

                              #15
                              Re: Hannspree T280H not turning on

                              Ok, so try powerboard as stand alone, prolly easiest way is unhook cable from powerboard to mainboard on mainboard side, leave it off for test, trace wires back and jumper #1 remote pin and #7 5vSB pin, so you are jumping thru the UNPLUGGED connector. Then plug power cord in and see if you have those missing voltages and see if the backlights come on.
                              Last edited by nomoresonys; 09-25-2023, 06:18 PM.

                              Comment

                              • lotas
                                Badcaps Legend
                                • Jan 2016
                                • 4474
                                • Russia

                                #16
                                Re: Hannspree T280H not turning on

                                Originally posted by nomoresonys
                                Ok, so try powerboard as stand alone, prolly easiest way is unhook cable from powerboard to mainboard on mainboard side, leave it off for test, trace wires back and jumper #1 remote pin and #7 5vSB pin, so you are jumping thru the UNPLUGGED connector. Then plug power cord in and see if you have those missing voltages and see if the backlights come on.
                                Just connect through a 1 kOhm resistor.

                                Comment

                                • nomoresonys
                                  Badcaps Legend
                                  • Jan 2013
                                  • 12086
                                  • U.S.

                                  #17
                                  Re: Hannspree T280H not turning on

                                  Resistor is good practice, a safety precaution, not needed if there is no mistake in making connections.
                                  Last edited by nomoresonys; 09-26-2023, 04:52 AM.

                                  Comment

                                  • lotas
                                    Badcaps Legend
                                    • Jan 2016
                                    • 4474
                                    • Russia

                                    #18
                                    Re: Hannspree T280H not turning on

                                    Originally posted by nomoresonys
                                    Resistor is good practice, a safety precaution, not needed if there is no mistake in making connections.
                                    It is always needed in such cases, firstly, it is not known what voltage is needed on the β€œremote” 3v or 5v, and secondly, it (the resistor) limits the voltage supply current.

                                    Comment

                                    • nomoresonys
                                      Badcaps Legend
                                      • Jan 2013
                                      • 12086
                                      • U.S.

                                      #19
                                      Re: Hannspree T280H not turning on

                                      Actually it's not worth debating, so go for the resistor, some have had unreliable results because of using the wrong size resistor, using the right size is fine.
                                      Last edited by nomoresonys; 09-26-2023, 06:37 AM.

                                      Comment

                                      • cschappa
                                        Craig
                                        • Sep 2023
                                        • 8
                                        • United States

                                        #20
                                        Re: Hannspree T280H not turning on

                                        I was able to jumper #1 & #7, I couldn't find a 1kohm resistor.

                                        No backlight, also no 12v or 5v.

                                        Comment

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