Announcement

Collapse
No announcement yet.

Toshiba 26AV600A

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #61
    Re: Toshiba 26AV600A

    Originally posted by nomoresonys View Post
    Check all the diodes on the powerboard, good place to start and easy enough to do.
    checked over the diodes no bad readings from any of them.

    Now I’m really stuck.

    Comment


      #62
      Re: Toshiba 26AV600A

      Maybe try testing powerboard, with cable from CN902 to mainboard UNHOOKED, use about a 1k resistor to jump PS_on to +5v pin and another resistor from ON/OFF to +5v, plug the power into powerboard, see if you get the backlights on and if those voltages come up.

      Comment


        #63
        Re: Toshiba 26AV600A

        Tried forcing it on with out the mainboard plugged in none of the voltages I was getting are appearing.

        Comment


          #64
          Re: Toshiba 26AV600A

          check R925 (0.1Ω) and R930 (0.43Ω), if they are ok, use hot ground to check the voltage on Q970 Drain (should be pfc voltage) if it is ok, check the voltage on C977 (15v)

          Comment


            #65
            Re: Toshiba 26AV600A

            Originally posted by R_J View Post
            check R925 (0.1Ω) and R930 (0.43Ω), if they are ok, use hot ground to check the voltage on Q970 Drain (should be pfc voltage) if it is ok, check the voltage on C977 (15v)
            r925
            0.2 Ω

            r930
            0.4 Ω.

            Comment


              #66
              Re: Toshiba 26AV600A

              The resistors are ok, so the fets are likely ok, Now check the voltages

              Comment


                #67
                Re: Toshiba 26AV600A

                So checked

                Q970
                396v

                c977
                13.18vdc

                C977 is meant to be 15 volts isn't it?

                Comment


                  #68
                  Re: Toshiba 26AV600A

                  The 13 volts is ok for the ic's vcc, Check the voltage on ic970, pin 7, and pin 5 (look at the schematic and locate a nearby component to check the voltage to avoid shorting the ic pins (IE: pin5 use C991 orR992)
                  It could be that IC870 is bad.

                  Comment


                    #69
                    Re: Toshiba 26AV600A

                    done these checks.

                    Pin 5
                    2.6mV

                    Pin 7
                    1.98V

                    Comment


                      #70
                      Re: Toshiba 26AV600A

                      It would seem the ic is in standby, pin 5 needs to be above 50mv. Check the two resistors, R932 (3.9k) and R992 (100Ω) if they are ok, check that the optocoupler is not bad and that C991 is not shorted

                      Comment


                        #71
                        Re: Toshiba 26AV600A

                        r932 is good
                        r992 is good
                        c991 isn't short
                        optocoupler isn't shorted.

                        Comment


                          #72
                          Re: Toshiba 26AV600A

                          optocoupler
                          2.91v on pin 1 using chassis as ground

                          2.0Mv on pin 4 using filter cap as ground.

                          Would it be safe to say this optocoupler is no good?
                          Last edited by Amraks; 05-29-2020, 12:18 AM.

                          Comment


                            #73
                            Re: Toshiba 26AV600A

                            I don't believe the optocoupler is the problem
                            The datasheet says that pin 4 provides a 2v reference voltage which should show up on one end of R932, This voltage is from the ic itself so I suspect if it is missing the ic is the problem. If the optocoupler is not shorted, then the 2 volts from pin4 should go through R932, R992 and back to pin5 (the standby pin) and should be around a minimum of 1.3v
                            It seems the circuit is slightly working and likely stuck in burts mode. otherwise you shoud not have any voltage on the 24v1 supply, this is where pin1 of the optocoupler gets its voltage and is getting 2.91v.
                            Last edited by R_J; 05-29-2020, 06:21 PM.

                            Comment


                              #74
                              Re: Toshiba 26AV600A

                              Originally posted by R_J View Post
                              I don't believe the optocoupler is the problem
                              The datasheet says that pin 4 provides a 2v reference voltage which should show up on one end of R932, This voltage is from the ic itself so I suspect if it is missing the ic is the problem. If the optocoupler is not shorted, then the 2 volts from pin4 should go through R932, R992 and back to pin5 (the standby pin) and should be around a minimum of 1.3v
                              It seems the circuit is slightly working and likely stuck in burts mode. otherwise you shoud not have any voltage on the 24v1 supply, this is where pin1 of the optocoupler gets its voltage and is getting 2.91v.

                              Cheers R_J and everyone else a new chip solved the issue and bought the TV back to life.

                              This TV bought some different symptoms to the table for when this chip goes bad anyway.

                              Comment


                                #75
                                Re: Toshiba 26AV600A

                                So which one was bad, IC870 or IC970?

                                Comment


                                  #76
                                  Re: Toshiba 26AV600A

                                  Originally posted by nomoresonys View Post
                                  So which one was bad, IC870 or IC970?
                                  I believe his final replacement was IC970.

                                  Comment


                                    #77
                                    Re: Toshiba 26AV600A

                                    Thanks Markus.

                                    Comment

                                    Working...
                                    X