Yamahaha RX-V679 DC PRT High

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • peterwheat
    Member
    • Aug 2020
    • 18
    • United States

    #21
    Re: Yamahaha RX-V679 DC PRT High

    When the unit was originally plugged in (I bought a house and it came with it, plugged into in wall speakers) the sound was very distorted and muffled at any volumes higher than a whisper. Out of curiosity, I had a speaker plugged in while taking apart, and tested with the unit dissembled. It sounded great, and the voltages at the speaker terminals were normal (read < 0.01 volts). However, as I put it back together, it seemed that the problem reappeared. I'm suspecting a loose connection somewhere possibly? What could cause all the speaker terminals to experience a higher than usual DC voltage?

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #22
      Re: Yamahaha RX-V679 DC PRT High

      If stand alone testing of the receiver using speakers directly connected to each channel and they sounds fine then I would investigate the house speaker wrings. Some time people will use un-insulated staple for staple down the wires.
      Is there also any external speaker switching box?
      You can also check the DCR of each house speaker, by measuring each pair of the speaker wires.
      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

      • peterwheat
        Member
        • Aug 2020
        • 18
        • United States

        #23
        Re: Yamahaha RX-V679 DC PRT High

        Originally posted by budm
        If stand alone testing of the receiver using speakers directly connected to each channel and they sounds fine then I would investigate the house speaker wrings. Some time people will use un-insulated staple for staple down the wires.
        Is there also any external speaker switching box?
        You can also check the DCR of each house speaker, by measuring each pair of the speaker wires.
        The standalone testing of the speaker varies as I am putting the unit back together. I tested the in wall speakers using a different receiver and they sound perfect, so the issue is certainly with the receiver.

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #24
          Re: Yamahaha RX-V679 DC PRT High

          OK, I misread about the speaker hook up, they sound fine when the receiver is disassembled.
          Did you verify that all the circuit boards mounting screws are tightened to the chassis, the chassis is being used as ground path for the board ground connections.
          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

          • peterwheat
            Member
            • Aug 2020
            • 18
            • United States

            #25
            Re: Yamahaha RX-V679 DC PRT High

            Originally posted by budm
            OK, I misread about the speaker hook up, they sound fine when the receiver is disassembled.
            Did you verify that all the circuit boards mounting screws are tightened to the chassis, the chassis is being used as ground path for the board ground connections.
            I have the chassis connected with alligator clips when dissembled. In fact, the issue gets worse with more assembly. Should I just put it back in use taken apart?

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #26
              Re: Yamahaha RX-V679 DC PRT High

              Originally posted by peterwheat
              I have the chassis connected with alligator clips when dissembled. In fact, the issue gets worse with more assembly. Should I just put it back in use taken apart?
              Sound like something's making wrong contacts when putting back together, pinched wires, etc.
              Last edited by budm; 08-07-2020, 02:15 PM.
              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

              • petehall347
                Badcaps Legend
                • Jan 2015
                • 4426
                • United Kingdom

                #27
                Re: Yamahaha RX-V679 DC PRT High

                maybe different length screws

                Comment

                • peterwheat
                  Member
                  • Aug 2020
                  • 18
                  • United States

                  #28
                  Re: Yamahaha RX-V679 DC PRT High

                  Originally posted by petehall347
                  maybe different length screws
                  I logged every group of screws so that wouldn't happen, so hopefully not that. Flexing the main board a little causes voltage at the speaker terminals and distorted sound, flexing it back stops the voltage. Poking around for loose components as best I can, but a bit difficult to touch everything while all connected. Can you flow these boards in the oven?

                  Comment

                  • budm
                    Badcaps Legend
                    • Feb 2010
                    • 40746
                    • USA

                    #29
                    Re: Yamahaha RX-V679 DC PRT High

                    Distorted sound on ALL speaker outputs?
                    If it is then It has to be something that is common to all the amp circuits, I would check the amplifier +/- power supplies Voltages while flexing the board, ground is also common to the circuits so you need to check that too.
                    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

                    • petehall347
                      Badcaps Legend
                      • Jan 2015
                      • 4426
                      • United Kingdom

                      #30
                      Re: Yamahaha RX-V679 DC PRT High

                      and that -14v i mentioned . or was it minus 24v ? anyway it connects to all the differential amps that control dc offset . i got a bit lost with that as it has a strange circuit .i thought maybe a servo . sorry just on a rant .

                      Comment

                      • peterwheat
                        Member
                        • Aug 2020
                        • 18
                        • United States

                        #31
                        Re: Yamahaha RX-V679 DC PRT High

                        Haha hopefully no servos buried in here. Watched the -12.4 volt line as I flexed and nothing weird happened. When the problem was occurring, still -12.4. Pressed on all the components I could find with my handy chopstick to see if anything wiggled free and popped the protection, but nothing. Ended up sliding a piece of rubber mat under the main board (didn't block any air holes, but I know it'll heat it up more than usual) sewed it back up, and it's firing away. I'm assuming there's a loose component in there somewhere that is giving me the issue. The odd thing is, the distortion increased and decreased w/ board flex. However, the voltages at the speaker terminals stayed at about 0.28 volts while flexing.

                        I'm sure it is just a temporary fix for right now, and not the ideal solution. I may pull it open in the future and see if I can't reflow things in the oven, but it works for right now.

                        For my reference though, where is the amplifier located on the board? It's not the lines coming out of the transformer, right?

                        Comment

                        • petehall347
                          Badcaps Legend
                          • Jan 2015
                          • 4426
                          • United Kingdom

                          #32
                          Re: Yamahaha RX-V679 DC PRT High

                          there are separate amplifiers all sharing the same power supply .

                          Comment

                          • budm
                            Badcaps Legend
                            • Feb 2010
                            • 40746
                            • USA

                            #33
                            Re: Yamahaha RX-V679 DC PRT High

                            "For my reference though, where is the amplifier located on the board? It's not the lines coming out of the transformer, right?"
                            What do you mean?
                            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

                            • peterwheat
                              Member
                              • Aug 2020
                              • 18
                              • United States

                              #34
                              Re: Yamahaha RX-V679 DC PRT High

                              How would I go about checking the main amplifier voltages?

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #35
                                Re: Yamahaha RX-V679 DC PRT High

                                Originally posted by peterwheat
                                How would I go about checking the main amplifier voltages?
                                What do you mean 'Main Amplifier'?
                                See service manual page 136, all the power amplifiers run from +/-61V power supplies and +/- 56V power supplies.
                                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

                                • peterwheat
                                  Member
                                  • Aug 2020
                                  • 18
                                  • United States

                                  #36
                                  Re: Yamahaha RX-V679 DC PRT High

                                  Thank you. I'll throw some leads on there and flex it around and see if the problem reproduces itself when I have a little time on my hands. I appreciate everyone's help, very considerate.

                                  Comment

                                  Related Topics

                                  Collapse

                                  • karatzdi
                                    Denon AVR 1908, High pitch noise on Surround back Left channel after long overhaul
                                    by karatzdi
                                    Hello,

                                    I know some might say... just buy another one. Sell it as parts..!

                                    So had this AMP for quite some time. Recently I saw light smoke coming out of the AMP. Had my fire extinguisher close by. Just kidding. Turned immediately all devices off from mains.
                                    Let things cool a bit, and opened up the amp device. I clearly saw on the main board which hosts the 5X amp (5.1), 3 10 ohms 1W resistors had their leads looking black, while the rest of the remaining 2 x 10 ohms were brownish as being installed from factory.

                                    Spent some time downloading the Service...
                                    06-11-2024, 08:38 AM
                                  • BTubbs200
                                    Dead Dell Latitude 5420 not receiving 20 volts from USB-C charger
                                    by BTubbs200
                                    Hello,

                                    Dell Latitude 5420 P137G
                                    Board: LA-K491P REV A01

                                    I have received this laptop which was described as "does not power on or accept charge." Battery shows no sign of charging when charger is plugged in, nor does the board show any signs of life when battery is unplugged and charger is plugged in. No light from the LED at all or any other indications of activity.

                                    Board seems to have no shorts, all power rails are fine and show high resistance.

                                    When charger is plugged in, voltage is present in 3.3V rail but absent in others....
                                    01-24-2025, 08:15 PM
                                  • hs5424
                                    Dynacord powermate 1600 protection on.
                                    by hs5424
                                    My first post from an old timer.
                                    I see here that this is a common problem with these Dynacord powered mixers. When the unit is powered on the protect led comes on straight away. I immediately checked the O/P transistors and removed them from the board (heat sink paste dried out so not a waste of time). All checked out OK. The main 80v + and - OK. However when I check for voltage on the inductors going to the speakers (o/p transistors removed) I found -30v on L501 which is the right side channel. The left side inductor shows zero volts. Am I correct in thinking that the right side is the...
                                    06-20-2025, 04:10 AM
                                  • ictc
                                    Philips MDP 3380/12 Blu-ray Player – No Power, Reset Signal Always High
                                    by ictc
                                    I'm troubleshooting a Philips MDP 3380/12 Blu-ray player that shows no signs of life. The display remains off, and no buttons respond.

                                    Inside, the power supply is working correctly, and all expected voltages on the mainboard match the service manual specifications. The CPU warms up slightly (checked with a thermal camera), the crystal oscillator is functioning, but the reset signal remains high at all times.

                                    The reset circuit appears to consist of two NPN transistors, one driven by 5V VCC and the other by 3.3V STBY, as shown in the attached schematic. Should the reset...
                                    02-25-2025, 12:15 PM
                                  • MisterAIL
                                    PS5 digital / No Power / No Beep / Good power supply
                                    by MisterAIL
                                    Hi everyone,

                                    Brought a non functionnal PS5. Apparently only a bad PSU...
                                    No beep, nothing.

                                    After some tests i found this :
                                    - PSU is fine (12 volts stable)
                                    - 12 volts line is shorted
                                    - DA9065 was fried, F7003 also => Replaced both of them, short is gone on 12 volts line, no dead short anywhere else.
                                    - By the way, nothing change. No signal, no power, no beep.

                                    Mesuring all rails with my workbench psu (12 volts input)
                                    - 0.00 amp drawing
                                    - 12 volts, 5 volts, 2 volts, 1,15 volts are presents (suppose new DA9065 do is...
                                    03-12-2024, 03:24 PM
                                  • Loading...
                                  • No more items.
                                  Working...