CRATE retrofex rfx30 blown output IC

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  • goontron
    5000!
    • Dec 2011
    • 4108
    • US

    #1

    CRATE retrofex rfx30 blown output IC

    DISCLAIMER: i only have half a f**king clue when it comes to SS audio equipment, so bear with me, i exist in the world of valve radios.

    i have a retrofex with a blown output IC, the visible numbers are:
    TDA2050
    88047VW
    SGP4

    along with the IC a 1 ohm resistor (R63) blew, if thats of any help, it usually is with valves but IDK about IC's. the fault was isolated to a bad (shorted) external speaker cord.
    Last edited by goontron; 10-06-2014, 09:13 PM.
    Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

    "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

    Excuse me while i do something dangerous


    You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

    Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

    Follow the white rabbit.
  • diif
    Badcaps Legend
    • Feb 2014
    • 6978
    • England

    #2
    Re: CRATE retrofex rfx30 blown output IC

    Something like this ?
    http://www.ebay.com/itm/like/180920315440?lpid=82

    Comment

    • goontron
      5000!
      • Dec 2011
      • 4108
      • US

      #3
      Re: CRATE retrofex rfx30 blown output IC

      yeah, it looks like that would work....Thanks
      Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

      "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

      Excuse me while i do something dangerous


      You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

      Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

      Follow the white rabbit.

      Comment

      • kaboom
        "Oh, Grouchy!"
        • Jan 2011
        • 2507
        • USA

        #4
        Re: CRATE retrofex rfx30 blown output IC

        Is that 1-ohm resistor between either pin 3 or 5 and the neg or pos supply?

        Make sure the new IC has both supply rails unless you like dumping one of them into the speaker.
        "pokemon go... to hell!"

        EOL it...
        Originally posted by shango066
        All style and no substance.
        Originally posted by smashstuff30
        guilty,guilty,guilty,guilty!
        guilty of being cheap-made!

        Comment

        • goontron
          5000!
          • Dec 2011
          • 4108
          • US

          #5
          Re: CRATE retrofex rfx30 blown output IC

          Originally posted by kaboom
          Is that 1-ohm resistor between either pin 3 or 5 and the neg or pos supply?

          Make sure the new IC has both supply rails unless you like dumping one of them into the speaker.
          the resistor is at pin5, after a diode. pin3 goes to a cap and the ribbon.
          this SS stuff is confusing...
          Attached Files
          Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

          "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

          Excuse me while i do something dangerous


          You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

          Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

          Follow the white rabbit.

          Comment

          • kaboom
            "Oh, Grouchy!"
            • Jan 2011
            • 2507
            • USA

            #6
            Re: CRATE retrofex rfx30 blown output IC

            Originally posted by goontron
            this SS stuff is confusing...
            It gets easier, believe me...

            After a few LM386 amps, I built a few TDA2002 ones back in the day.

            It's funny- I tried building two amps on one board. The lousy layout resulted in GND and feedback via B+. One IC shorted and the other kept oscillating, even w/o it's "partner."

            That was over 12 years ago- I've learned lots since then, and you will too.

            It looks like they're clipping that signal with a diode (fed by that resistor) and sending part of it back down the ribbon. To the preamp for some kind of AGC?

            Can you post a topside board pic? Pins 3 and 5 both go directly to their power feeds, doubled-up wires in the ribbon cable.
            "pokemon go... to hell!"

            EOL it...
            Originally posted by shango066
            All style and no substance.
            Originally posted by smashstuff30
            guilty,guilty,guilty,guilty!
            guilty of being cheap-made!

            Comment

            • goontron
              5000!
              • Dec 2011
              • 4108
              • US

              #7
              Re: CRATE retrofex rfx30 blown output IC

              it has a DSP as well as an AGC, stand by for pics of all boards.
              Last edited by goontron; 10-12-2014, 09:36 PM.
              Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

              "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

              Excuse me while i do something dangerous


              You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

              Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

              Follow the white rabbit.

              Comment

              • goontron
                5000!
                • Dec 2011
                • 4108
                • US

                #8
                Re: CRATE retrofex rfx30 blown output IC

                pics.
                Attached Files
                Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                Excuse me while i do something dangerous


                You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                Follow the white rabbit.

                Comment

                • kaboom
                  "Oh, Grouchy!"
                  • Jan 2011
                  • 2507
                  • USA

                  #9
                  Re: CRATE retrofex rfx30 blown output IC

                  Okay, those two diodes are the clamping diodes as shown in the datasheet.

                  Check the green poly cap for shorts. It and that resistor go from pin 4 of the IC (output) to GND. If that cap shorts, the 1-ohm resistor gets full output signal voltage.

                  Or, if the amp oscillates, the low Xc of the cap causes that resistor to absorb the parasites. If it keeps up for too long, the resistor smokes.

                  What's the value of those two electrolytics? From pin 3 and 5, to common.

                  I'd use ones no smaller than 470u, with voltage rating above the supplies. There should be a .1u MLCC across each of those decoupling 'lytics. Those two 'lytics should be low-esr- PW/HE/FC/FM, etc.

                  Those TDAs have a need to be tamed- that 1-ohm (R63) will not burn up like that unless the poly cap shorts or the amp oscillates.

                  Edit- See annotated pic.
                  Attached Files
                  Last edited by kaboom; 10-12-2014, 09:57 PM.
                  "pokemon go... to hell!"

                  EOL it...
                  Originally posted by shango066
                  All style and no substance.
                  Originally posted by smashstuff30
                  guilty,guilty,guilty,guilty!
                  guilty of being cheap-made!

                  Comment

                  • goontron
                    5000!
                    • Dec 2011
                    • 4108
                    • US

                    #10
                    Re: CRATE retrofex rfx30 blown output IC

                    the resistor is still good, just dark. the fault was a shorted ext speaker cable, as seen by it killing a valve amp too. (already fixed)
                    Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                    "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                    Excuse me while i do something dangerous


                    You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                    Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                    Follow the white rabbit.

                    Comment

                    • kaboom
                      "Oh, Grouchy!"
                      • Jan 2011
                      • 2507
                      • USA

                      #11
                      Re: CRATE retrofex rfx30 blown output IC

                      Originally posted by goontron
                      the resistor is still good, just dark. the fault was a shorted ext speaker cable, as seen by it killing a valve amp too. (already fixed)
                      Do you want a callback, or do you want to fix it (hopefully) for good?

                      Now check that green poly cap.
                      "pokemon go... to hell!"

                      EOL it...
                      Originally posted by shango066
                      All style and no substance.
                      Originally posted by smashstuff30
                      guilty,guilty,guilty,guilty!
                      guilty of being cheap-made!

                      Comment

                      • goontron
                        5000!
                        • Dec 2011
                        • 4108
                        • US

                        #12
                        Re: CRATE retrofex rfx30 blown output IC

                        Originally posted by kaboom
                        Do you want a callback, or do you want to fix it (hopefully) for good?

                        Now check that green poly cap.
                        its failed, open. no capacitance, no resistance.
                        Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                        "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                        Excuse me while i do something dangerous


                        You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                        Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                        Follow the white rabbit.

                        Comment

                        • kaboom
                          "Oh, Grouchy!"
                          • Jan 2011
                          • 2507
                          • USA

                          #13
                          Re: CRATE retrofex rfx30 blown output IC

                          Originally posted by goontron
                          its failed, open. no capacitance, no resistance.
                          And that means the replacement IC will oscillate and die.

                          The original IC oscillated for whatever reason, as evidenced by that smoked resistor. The current went thru the series combination of that cap and R63. After a while, the cap shorted, causing excessive dissipation in R63. Then, it opened, now leaving a fault (lack of parasitic suppression) that will take out the new IC.

                          Follow the suggestions in that annotated pic.

                          Just because you isolated a bad speaker cable doesn't mean you don't have more work to do.

                          Don't replace that IC without at least replacing that cap and resistor!

                          I had a TDA2002 amp, a Cebek module, with improper routing/bonding of the grounds, taking power GND a bit too near the input. Guess how high up it was oscillating? In the AM BCB! Only 2-3W out... Got 10W out (4-ohms) after redoing the GNDs.
                          "pokemon go... to hell!"

                          EOL it...
                          Originally posted by shango066
                          All style and no substance.
                          Originally posted by smashstuff30
                          guilty,guilty,guilty,guilty!
                          guilty of being cheap-made!

                          Comment

                          • goontron
                            5000!
                            • Dec 2011
                            • 4108
                            • US

                            #14
                            Re: CRATE retrofex rfx30 blown output IC

                            shopping list: one (NLA) TDA2050, one 1/2watt 1ohm resistor, one .22uf 250v poly capacitor, and one 1amp 250v fuse.
                            Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                            "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                            Excuse me while i do something dangerous


                            You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                            Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                            Follow the white rabbit.

                            Comment

                            • kaboom
                              "Oh, Grouchy!"
                              • Jan 2011
                              • 2507
                              • USA

                              #15
                              Re: CRATE retrofex rfx30 blown output IC

                              Originally posted by goontron
                              shopping list: one (NLA) TDA2050, one 1/2watt 1ohm resistor, one .22uf 250v poly capacitor, and one 1amp 250v fuse.
                              I typed "1-2W" meaning one - two watt, as in "a resistor between 1 and two watts," not a half-watt resistor!

                              At this point, go with a two-watter.

                              Mouser P/Ns:

                              660-MOSX2CT52R1R0J -R63
                              594-2222-368-25224 -Poly cap
                              512-UF4004 x2
                              80-C410C224K1R x2 -MLCCs to go across decoupling 'lytics, below
                              647-UHE1V471MPD1TD x2-if originals are 35V
                              647-UHE1H471MPD x2-if originals are 50V

                              The IC you'll have to get elsewhere:
                              http://www.ebay.com/itm/1-x-TDA2050-...-/301246868204

                              Is the fuse slow-blow? What size is it? 1-1/4x1/4 or 5x20mm?
                              Last edited by kaboom; 10-12-2014, 11:06 PM.
                              "pokemon go... to hell!"

                              EOL it...
                              Originally posted by shango066
                              All style and no substance.
                              Originally posted by smashstuff30
                              guilty,guilty,guilty,guilty!
                              guilty of being cheap-made!

                              Comment

                              • goontron
                                5000!
                                • Dec 2011
                                • 4108
                                • US

                                #16
                                Re: CRATE retrofex rfx30 blown output IC

                                Originally posted by kaboom
                                I typed "1-2W" meaning one - two watt, as in "a resistor between 1 and two watts," not a half-watt resistor!

                                At this point, go with a two-watter.

                                Mouser P/Ns:

                                660-MOSX2CT52R1R0J -R63
                                594-2222-368-25224 -Poly cap
                                512-UF4004 x2
                                80-C410C224K1R x2 -MLCCs to go across decoupling 'lytics, below
                                647-UHE1V471MPD1TD x2-if originals are 35V
                                647-UHE1H471MPD x2-if originals are 50V

                                The IC you'll have to get elsewhere:
                                http://www.ebay.com/itm/1-x-TDA2050-...-/301246868204

                                Is the fuse slow-blow? What size is it? 1-1/4x1/4 or 5x20mm?
                                ok. the fuse wasn't a slow-blow, but it should be, that much i can gather.i found one floating in the bottom of my toolbox.
                                Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                                "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                                Excuse me while i do something dangerous


                                You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                                Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                                Follow the white rabbit.

                                Comment

                                • goontron
                                  5000!
                                  • Dec 2011
                                  • 4108
                                  • US

                                  #17
                                  Re: CRATE retrofex rfx30 blown output IC

                                  the lytecs have high ESR, rebuilding the whole daughter board.
                                  Last edited by goontron; 10-13-2014, 12:45 PM.
                                  Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

                                  "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

                                  Excuse me while i do something dangerous


                                  You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

                                  Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

                                  Follow the white rabbit.

                                  Comment

                                  • kaboom
                                    "Oh, Grouchy!"
                                    • Jan 2011
                                    • 2507
                                    • USA

                                    #18
                                    Re: CRATE retrofex rfx30 blown output IC

                                    Originally posted by goontron
                                    the lytecs have high ESR, rebuilding the whole daughter board.
                                    You may have to use smaller caps than 470u, if space is tight. Don't go below 220u.
                                    http://www.mouser.com/Search/Refine....d=nichicon+uhe
                                    "pokemon go... to hell!"

                                    EOL it...
                                    Originally posted by shango066
                                    All style and no substance.
                                    Originally posted by smashstuff30
                                    guilty,guilty,guilty,guilty!
                                    guilty of being cheap-made!

                                    Comment

                                    • kaboom
                                      "Oh, Grouchy!"
                                      • Jan 2011
                                      • 2507
                                      • USA

                                      #19
                                      Re: CRATE retrofex rfx30 blown output IC

                                      Also, the stuff on the other side of that board can stay:

                                      C34
                                      C37
                                      R58
                                      R59

                                      But change that coupling cap.
                                      "pokemon go... to hell!"

                                      EOL it...
                                      Originally posted by shango066
                                      All style and no substance.
                                      Originally posted by smashstuff30
                                      guilty,guilty,guilty,guilty!
                                      guilty of being cheap-made!

                                      Comment

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