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    Sansui AU9500, capacitor blows

    I have Sansui amplifier AU9500,, no sound, I found fuse 2 amperes, 7 amperes burns, I found too 3.3 uf 100 volts completly bulging under driver board, 1 transistor output 2SA679 shorted,and I found too the 4 capacitors 4700UF 63 volts they have not good value, I changed all these components and one of 2 capacitors 3.3 uf 100 volts is going very hot after 30 seconds, do I have power supply problem?

    #2
    Re: Sansui AU9500, capacitor blows

    A 7 ampere fuse burns out, too, when rated for only 2 amperes? Sounds like a bad transistor to me! (besides the bad caps, of course!)
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      #3
      Re: Sansui AU9500, capacitor blows

      Yes, I change too 2 transistors audio output on the left channel, and same problem the 3.3 uf 100 volts under the driver board become very hot and blowing up

      Comment


        #4
        Re: Sansui AU9500, capacitor blows

        you put the cap in backwards or the power supply needs work

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          #5
          Re: Sansui AU9500, capacitor blows

          The capacitor was completly bulging before I work on the amplifier, I put the cap with good polarity and I put a 160 volts capacitor( original was 100 volts), I think problem is in the Power Supply

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            #6
            Re: Sansui AU9500, capacitor blows

            did this amp ever work for you ? a little will be a big help ..
            the only caps i see with 33 is 33pf .

            Comment


              #7
              Re: Sansui AU9500, capacitor blows

              What are the LOCATION NUMBERS of the componemts that you changed ? Which capacitor is getting hot? C???? For a capacitor to get hot it is either in backwards or has way too much voltage across it.

              Comment


                #8
                Re: Sansui AU9500, capacitor blows

                hold on a bit .. no way too much voltage got the 100v cap hot . 3.3uf isnt a value in that amp as far as i can see .. if you cant work out board designator id tell us what it connects to . and if there are holes in the board for it . it is possibly a late addition from factory .
                some nice pictures will help .
                Last edited by petehall347; 07-30-2021, 06:53 PM.

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                  #9
                  Re: Sansui AU9500, capacitor blows

                  Either something is drawing power like a SOB, or that cap is backwards or wrong value or high ESR.

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                    #10
                    Re: Sansui AU9500, capacitor blows

                    Check on this photo the 2 new capacitors I put, one is blue and the other is black, I check on schematic and is not listed
                    Attached Files

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                      #11
                      Re: Sansui AU9500, capacitor blows

                      trace where the wires go to what the caps connect to .and tell us ..

                      Comment


                        #12
                        Re: Sansui AU9500, capacitor blows

                        think i have found the problem .i found an original pic .. look where the blown up one connects to .
                        Attached Files

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                          #13
                          Re: Sansui AU9500, capacitor blows

                          In one version the caps were .01µf disc caps, and electrolytics in a different version.
                          Attached Files
                          Last edited by R_J; 07-31-2021, 02:32 PM.

                          Comment


                            #14
                            Re: Sansui AU9500, capacitor blows

                            so did it get fixed or not ?

                            Comment


                              #15
                              Re: Sansui AU9500, capacitor blows

                              My version is with electrolitic cap and when I change it I verify twice if it's polarity is ok

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                                #16
                                Re: Sansui AU9500, capacitor blows

                                fit it as seen in the pictures .

                                Comment


                                  #17
                                  Re: Sansui AU9500, capacitor blows

                                  I check voltage on the 2 electrolytics and it seems normal one gray wire have -49 volts and the other with yellow wire have +49 volts , they connect directly on bridge rectifier, I try to switch on amplifier and I remark distortion on one channel and after 1 minute the capacitor goes very hot

                                  Comment


                                    #18
                                    Re: Sansui AU9500, capacitor blows

                                    the connections are wrong .. try looking at the pictures we spent time looking for and posting for you .

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