technika 42 lcd 910 power probs

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  • exmortis
    Member
    • Feb 2013
    • 27
    • u.k

    #1

    technika 42 lcd 910 power probs

    hi having probs with this , the unit powers up and the screen lights up for 20sec's and then powers down again , and the psu 17PW01-4 buzz's any ideas with this issue common i seen, cant see any badcaps on the board.
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #2
    Re: technika 42 lcd 910 power probs

    Your fault is different from last guy's. Check 24V across CapXon on inverters.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

    Comment

    • exmortis
      Member
      • Feb 2013
      • 27
      • u.k

      #3
      Re: technika 42 lcd 910 power probs

      Originally posted by tom66
      Your fault is different from last guy's. Check 24V across CapXon on inverters.

      ok all new to me , so i wouldnt know how to check that , i been told it could be a diode gone open letting through A.C

      Comment

      • exmortis
        Member
        • Feb 2013
        • 27
        • u.k

        #4
        Re: technika 42 lcd 910 power probs

        Originally posted by exmortis
        ok all new to me , so i wouldnt know how to check that , i been told it could be a diode gone open letting through A.C
        also the screen does not display anything , just the backlight on a black background ?

        Comment

        • vinceroger69
          Badcaps Legend
          • Mar 2012
          • 6714
          • uk

          #5
          Re: technika 42 lcd 910 power probs

          is you multi meter auto ranging or manual can you post pictures of the boards on your set they we can point out for you the test points etc.

          Comment

          • exmortis
            Member
            • Feb 2013
            • 27
            • u.k

            #6
            Re: technika 42 lcd 910 power probs

            Originally posted by vinceroger69
            is you multi meter auto ranging or manual can you post pictures of the boards on your set they we can point out for you the test points etc.
            manual meter i add some pic's
            Attached Files
            Last edited by exmortis; 02-22-2013, 04:55 AM.

            Comment

            • exmortis
              Member
              • Feb 2013
              • 27
              • u.k

              #7
              Re: technika 42 lcd 910 power probs

              Originally posted by exmortis
              manual meter i add some pic's

              the buzzing is coming from the little transformer fella i have high marked on the pic's , also marked these diodes which i was informed might be at fault

              Comment

              • vinceroger69
                Badcaps Legend
                • Mar 2012
                • 6714
                • uk

                #8
                Re: technika 42 lcd 910 power probs

                put you meter on diode test and the three diodes you have highlighted should have a reading in one direction only if any read odd you will have to unsolder 1 leg on each diode and then retest them.
                tom will explain what he needs tested and how ie meter setting etc if your not sure.
                if your not sure of the meter settings post a picture up and we will highlight the diode and dc settings for you
                Last edited by vinceroger69; 02-22-2013, 05:12 AM.

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: technika 42 lcd 910 power probs

                  This pic: https://www.badcaps.net/forum/attach...8&d=1361530364

                  Two brown caps (cylinders) on inverter board: check voltage across them.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                  Comment

                  • exmortis
                    Member
                    • Feb 2013
                    • 27
                    • u.k

                    #10
                    Re: technika 42 lcd 910 power probs

                    Originally posted by tom66
                    This pic: https://www.badcaps.net/forum/attach...8&d=1361530364

                    Two brown caps (cylinders) on inverter board: check voltage across them.
                    hi all thanks for quick replys ok

                    the diodes i get the same for all 3 a reading of 127-130

                    and the voltages accross the brown caps one reads 24v and the other only 5v the t.v slips back into standby, the caps look like they have been changed before lots of flux resin and moody solder joints.

                    Comment

                    • exmortis
                      Member
                      • Feb 2013
                      • 27
                      • u.k

                      #11
                      Re: technika 42 lcd 910 power probs

                      Originally posted by exmortis
                      hi all thanks for quick replys ok

                      the diodes i get the same for all 3 a reading of 127-130

                      and the voltages accross the brown caps one reads 24v and the other only 5v the t.v slips back into standby, the caps look like they have been changed before lots of flux resin and moody solder joints.
                      ok got 24v from both brown caps
                      of them on the invertor boards before she shuts down .

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #12
                        Re: technika 42 lcd 910 power probs

                        Ah, so you get 24V, then it rapidly falls off? When it does this, does the power LED begin blinking?
                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                        Comment

                        • exmortis
                          Member
                          • Feb 2013
                          • 27
                          • u.k

                          #13
                          Re: technika 42 lcd 910 power probs

                          Originally posted by tom66
                          Ah, so you get 24V, then it rapidly falls off? When it does this, does the power LED begin blinking?
                          power led does not blink at all, i changed some of the caps on the isolated side of the psu, same as the other chap did, and now it switches on and then back off within a couple of seconds

                          Comment

                          • exmortis
                            Member
                            • Feb 2013
                            • 27
                            • u.k

                            #14
                            Re: technika 42 lcd 910 power probs

                            Originally posted by exmortis
                            power led does not blink at all, i changed some of the caps on the isolated side of the psu, same as the other chap did, and now it switches on and then back off within a couple of seconds
                            i double check the led on the front tho now

                            Comment

                            • exmortis
                              Member
                              • Feb 2013
                              • 27
                              • u.k

                              #15
                              Re: technika 42 lcd 910 power probs

                              Originally posted by exmortis
                              i double check the led on the front tho now
                              blue button stays on now solid on the front .

                              Comment

                              • exmortis
                                Member
                                • Feb 2013
                                • 27
                                • u.k

                                #16
                                Re: technika 42 lcd 910 power probs

                                Originally posted by exmortis
                                blue button stays on now solid on the front .
                                i replaced the caps in red on the pic, now she switches on then off .
                                Attached Files

                                Comment

                                • exmortis
                                  Member
                                  • Feb 2013
                                  • 27
                                  • u.k

                                  #17
                                  Re: technika 42 lcd 910 power probs

                                  Originally posted by exmortis
                                  i replaced the caps in red on the pic, now she switches on then off .
                                  or completely stuck in standby mode help

                                  Comment

                                  • tom66
                                    EVs Rule
                                    • Apr 2011
                                    • 32560
                                    • UK

                                    #18
                                    Re: technika 42 lcd 910 power probs

                                    Do you have 24V on those caps briefly when power is first applied to the set?
                                    What brand and series of capacitors did you use?
                                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                    Comment

                                    • exmortis
                                      Member
                                      • Feb 2013
                                      • 27
                                      • u.k

                                      #19
                                      Re: technika 42 lcd 910 power probs

                                      Originally posted by tom66
                                      Do you have 24V on those caps briefly when power is first applied to the set?
                                      What brand and series of capacitors did you use?
                                      yeah i get 24v the it drops off and the cap's have no brand just some i picked up at the local electronics shop to match the ones to replace , 470micro 16v

                                      but the behaviour of the fault has now changed

                                      Comment

                                      • tom66
                                        EVs Rule
                                        • Apr 2011
                                        • 32560
                                        • UK

                                        #20
                                        Re: technika 42 lcd 910 power probs

                                        You need to use low-esr capacitors. Farnell sell them as do RS. Capacitors from the average shop can cause lots of issues. Good capacitors to use are Panasonic FC, FM or FR.
                                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                        Comment

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