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Yamaha RXV 465 no display and power problem

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    Yamaha RXV 465 no display and power problem

    Hi,

    I am looking for getting some assistance regarding the above amplifier.

    In present condition, when power switch is pressed, i only hear a relay click, so it is in protection mode.

    When direct + tone control and stand by is pressed for some time, it gives me three relay clicks

    1. For turning on the small standby power supply.
    2. For the supply of the power to the amplifier board.
    3. For the speaker relays.

    (all these are my guess).

    when turned on by the 3 buttons pressed it remains on but no display.

    Till now i have checked only for the DC output at the emitter resistor and there is a small ( 2 to 5 volts ) dc on them as the first relay clicks, then it settles to almost 0 volts.

    Please help me in getting further with the diagnosis of this unit. i have the required testing and measurement tools and the schematic.

    i am stuck

    Regards,
    Hemant.

    #2
    Re: Yamaha RXV 465 no display and power problem

    A couple voltages need for the FL display to work are filament voltage which are about 3-4 volts AC and -VP which is around -30 volts

    Page 115, plug CB403, you should measure 3-4 vac between the F1 & F2 pins and -30 vdc from ground to -VP
    Other voltages to check are: page 117
    + & - 12 volts from ic103 & ic104
    +Bv & -Bv should be around +&- 50vdc, they supply the stk-*** ic's You said you measured close to o volts on the R1046 & R1068 so I suspect the stk ic's are ok.
    When you press the power button you should here a relay click, that is the one turning on the main transformer.

    With the unit in standby, press and hold the "STRAIGHT" button and press standby/on , do you get a menu?
    Last edited by R_J; 06-22-2018, 09:11 AM.

    Comment


      #3
      Re: Yamaha RXV 465 no display and power problem

      Thank you R_J for your interest in helping me on this.
      Voltages between F1 and F2 is 5 vac ( measured with no dmm pin on ground )

      Output of IC 103 is 11.3 v
      Output of IC 104 IS -12.7v
      +B is 25.4 v
      -B is -27.1v
      -VP is -39.5v dc

      Also, nothing on display comes up when STRAIGHT and standby/on is pressed and hold.

      All these measurements were done with the direct+tone control+standby press and hold method.
      Will be checking for the low +Band -B readings.

      Please suggest if i am missing anything.

      Regards,

      Comment


        #4
        Re: Yamaha RXV 465 no display and power problem

        Do i need to check the low voltage 25 and 27v or this is controlled by the processor?

        Comment


          #5
          Re: Yamaha RXV 465 no display and power problem

          Originally posted by hemant_2222 View Post
          Do i need to check the low voltage 25 and 27v or this is controlled by the processor?
          Do you mean +5 volts and +3.3 and lower, yes.
          Page 112, there is +5.5v into ic21, it should output 3.4M, there is also Q200 it should output +3.3S, but this voltage is switched by Q201, Do you have 3.4 volts on Q201 base?

          Comment


            #6
            Re: Yamaha RXV 465 no display and power problem

            Sorry i mean, do i need to check the +B and -B, as they are lower then 50v.

            Also, i dont have the Q201 in the ckt.

            Comment


              #7
              Re: Yamaha RXV 465 no display and power problem

              Ok, so what is the B+ & B- voltage on C1055 & C1056? (page 117) The B+- could be low due to the AMP_LMT signal missing from the micro if its not functioning correctly
              Last edited by R_J; 06-23-2018, 01:32 PM.

              Comment


                #8
                Re: Yamaha RXV 465 no display and power problem

                Yes, the B and -B were same (25 and -27) measured across the capacitors C1055 and C1056.

                Also, is the absence of Q201 a concern?

                Comment


                  #9
                  Re: Yamaha RXV 465 no display and power problem

                  I believe the voltage across C1055 and across C1056 is low. because RY100 is not activated and is supplying the D1017 bridge with a lower voltage, It is being supplied by AC_BL and not AC_BH. The RY100 is controled by microprocessor ic20.
                  Does pushing the power button have any effect on the amp?
                  Locate the eeprom ic22 and check the voltages on it, especially pin8 +3.4 volts


                  Q201 may not be used on this model, I see a (&2) beside it and it is within a dotted box around it.
                  Are ic21 & Q200 there? does the ic have +5v in and 3.4v out for the +3.3m supply and does q200 have 3.4 in and out? (q201 may not be used on this model)
                  Last edited by R_J; 06-24-2018, 10:29 AM.

                  Comment


                    #10
                    Re: Yamaha RXV 465 no display and power problem

                    Hi,

                    When the power switch is pressed, the only relay that clicks for 3 seconds is the main relay RY371..the main power supply relay.

                    IC 22 has 3.3 at pin 8
                    Q200 has pin 3 at 2.88 and pin 4 at 3.33 volts
                    IC 21 has approx 5.41 volts at input and 3.33v as output.

                    Some readings of CB23 are as below,
                    Sp_imp ..3.3
                    Ps1_PRT 0.06
                    AMP_LMT 1.12
                    AMP_OLV 0.01
                    I_PRT 0.01
                    DC_PRT 0.02
                    VOL_SCK 0.0
                    DGNG 0.0
                    VOL_MOSI 0.0
                    MUTE_SW --10.8V

                    MUTE Z3 and Z2 are 0 volts

                    Comment


                      #11
                      Re: Yamaha RXV 465 no display and power problem

                      Readings of CB 24 are as under

                      +3.3M...3.3v
                      DGND. 0.01
                      ACPWR_DET 3.03
                      RESET 3.30
                      PRY 3.23
                      DEST 1.08

                      may be if this could help us to narrow down the problem.

                      Regards,

                      Comment


                        #12
                        Re: Yamaha RXV 465 no display and power problem

                        By pressing the power button and having ry371 activate, tells me the microprocessor seems to be functioning as it understands the key command and outputs the PRY logic
                        Can you explain clicks for 3 seconds, does it keep clicking or click (on) then click (off) after 3 seconds?

                        I am going back to your first post about the 2-5 volts on the resistors, that could be what is preventing the amp from turning on, even the display.
                        which resistors had that 2-5 volts, there are 5 sets of resistors
                        Last edited by R_J; 06-25-2018, 09:45 AM.

                        Comment


                          #13
                          Re: Yamaha RXV 465 no display and power problem

                          The relay click ON then click OFF.

                          Comment


                            #14
                            Re: Yamaha RXV 465 no display and power problem

                            If it clicks on then off how did you measure the 2-5 volts on the resistors? That relay controls the main tranformer, if it turns off you won't get any voltage on the resistors.
                            check the center of the dual resistor and press power and record the voltage, you need to do this for all 5 resistor sets.
                            I suspect one of the stk's is bad.
                            Till now i have checked only for the DC output at the emitter resistor and there is a small ( 2 to 5 volts ) dc on them as the first relay clicks, then it settles to almost 0 volts.
                            the reason it settles to 0 is the relay turned the power off.
                            Last edited by R_J; 06-25-2018, 10:58 AM.

                            Comment


                              #15
                              Re: Yamaha RXV 465 no display and power problem

                              Yes, there is voltage spike with the first relay click then it drops to zero after the second relay click..power off.

                              With 3 buttons pressed, there is a voltage spike after the first relay click, drops to zero..then second relay click...then the third click and the receiver is ON..but no display. Atleast voltage measurements can be taken.

                              So, is it that the micro knows there is problem and it switches AC_BL and not AC_BH, which is needed for the stk's.

                              For my understanding please, why even the receiver is turned ON with the 3 button method.

                              Also, is there a way to isolate the Stk's one by one or it needs to be removed check thwn remove the other one.

                              Regards,

                              Comment


                                #16
                                Re: Yamaha RXV 465 no display and power problem

                                check the center of the dual resistor and press power and record the voltage, you need to do this for all 5 resistor sets.
                                The 3 button press bypasses the protection (except for the excess current detect) When you did this test did you see the "SLEEP" segment lit up on the display?
                                Last edited by R_J; 06-25-2018, 11:09 AM.

                                Comment


                                  #17
                                  Re: Yamaha RXV 465 no display and power problem

                                  Here are the voltages,

                                  IC101...
                                  R1035...3.97
                                  R1056..4.04

                                  IC100
                                  R1068..3.76
                                  R1046..4.19
                                  R1067..2.07v.

                                  The display is still off...For me this is no" SLEEP"..

                                  Comment


                                    #18
                                    Re: Yamaha RXV 465 no display and power problem

                                    At this point I would either remove the stk ic or at least isolate the pins 1,2,3 & 8. I would try ic101 first

                                    Comment


                                      #19
                                      Re: Yamaha RXV 465 no display and power problem

                                      I will try this tommorow, as its late night now.

                                      Thank you R_J.

                                      Regards,

                                      Comment


                                        #20
                                        Re: Yamaha RXV 465 no display and power problem

                                        With the stk pins removed, the display does not come up.
                                        IC 100 pins removed, no change but DC offset gone on its 3 resistor.

                                        IC 101 pins removed, no change but here also dc offset gone.

                                        The only difference observed was with the stk pins removed and with 3 buttons pressed ..the voltage level differs that is +B is 26 v and -B is 32.5v.

                                        Also, now there is simultaneous switching of all the relays, i think, because the relay switching noise is more but all these for very short duration.

                                        Let me know, if this is confusing.

                                        Regards,

                                        Comment

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