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Strange malfunctioning LED audio peak level meter problem

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    #21
    Re: Strange malfunctioning LED audio peak level meter problem

    The led's are the size of a grain of salt. I touched a couple and they went out too. I'm going to have to find an old computer running windows 7 so I can use the only usb microscope I have (Veho Discovery VMS004).

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      #22
      Re: Strange malfunctioning LED audio peak level meter problem

      well you probably need to replace the lot - so the brightness matches

      i would be tempted to build a new one possibly using a chinese vu meter module as a base and making a new led board to match the original spacings.
      Last edited by stj; 08-12-2020, 07:34 AM.

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        #23
        Re: Strange malfunctioning LED audio peak level meter problem

        Originally posted by stj View Post
        well you probably need to replace the lot - so the brightness matches

        i would be tempted to build a new one possibly using a chinese vu meter module as a base and making a new led board to match the original spacings.
        Thanks. The more I look at it, the micro sized led's would be beyond my capabilities. Still looking for an old windows 7 pc to use my microscope. Lol

        From what I can see with limited magnification it appears that there are tiny single strand wires coming off of the leds!!

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          #24
          Re: Strange malfunctioning LED audio peak level meter problem

          so what computer are you using now?
          i cant believe you cam a HID/cam device that wont just work in Linux or other windows versions.

          the wires are bond leads made of gold and welded at each end.

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            #25
            Re: Strange malfunctioning LED audio peak level meter problem

            Originally posted by stj View Post
            so what computer are you using now?
            i cant believe you cam a HID/cam device that wont just work in Linux or other windows versions.

            the wires are bond leads made of gold and welded at each end.
            Veho Discovery vms-004 usb microscope

            Worked years ago on old laptop I had. Windows 10 doesn't have a driver
            Last edited by JimBanville; 08-12-2020, 09:38 AM.

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              #26
              Re: Strange malfunctioning LED audio peak level meter problem

              Originally posted by JimBanville View Post
              Veho Discovery vms-004 usb microscope

              Worked years ago on old laptop I had. Windows 10 doesn't have a driver
              Read a review on amazon ao got it to work with my camera app!

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                #27
                Re: Strange malfunctioning LED audio peak level meter problem

                So I can see the microscopic wires and pads dislodged from the led's. Thanks! Now...how to reaffix them? Its insanely small.

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                  #28
                  Re: Strange malfunctioning LED audio peak level meter problem

                  pics
                  Attached Files

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                    #29
                    Re: Strange malfunctioning LED audio peak level meter problem

                    Pic
                    Attached Files

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                      #30
                      Re: Strange malfunctioning LED audio peak level meter problem

                      you cant fix them, you have to scrape them off the pads and solder tiny smd leds

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                        #31
                        Re: Strange malfunctioning LED audio peak level meter problem

                        You can test each LED as suggested, and also use high power magnifying glass each bonding wire of the LED.
                        I also see strange trace layouts.
                        I am also surprised that exposed bonding and die last this long, but since they cannot put black blob on top like they did for the IC since they are LED, they could have put on clear sealer instead on the LED's.
                        Attached Files
                        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

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                          #32
                          Re: Strange malfunctioning LED audio peak level meter problem

                          Originally posted by stj View Post
                          you cant fix them, you have to scrape them off the pads and solder tiny smd leds
                          Ok. I'm probably going to relocate this board and run jumper wires from it to individual wired-led's mounted into the plastic housing that mounts to the cassette player's face.

                          My understanding is that 1 signal goes to one side (let's called it "+" side) of the 1st, 4th, 7th, and 10th led's of both top and bottom rows. Now the other side (let's call it "-" side) of the 1st led goes to the + side of 2nd led. The - side of 2nd led goes to + side of 3rd led. The - side of 3rd led goes back to the IC. This same scenario is repeated for all the groups of 3 led's. There are 4 sets of 3 led groups on each row.

                          Can someone recommend wired-led's? I'll need some green, amber/yellow and red. They should fit into the plastic housing.

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                            #33
                            Re: Strange malfunctioning LED audio peak level meter problem

                            Plastic housing
                            Attached Files

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                              #34
                              Re: Strange malfunctioning LED audio peak level meter problem

                              Originally posted by budm View Post
                              You can test each LED as suggested, and also use high power magnifying glass each bonding wire of the LED.
                              I also see strange trace layouts.
                              I am also surprised that exposed bonding and die last this long, but since they cannot put black blob on top like they did for the IC since they are LED, they could have put on clear sealer instead on the LED's.
                              Unfortunately I have neither the tools nor skills to both view, manipulate, and solder those microscopic wires in place.
                              I CAN solder some jumper wires to some of those larger exposed traces and test points to some wired-led's.

                              Based on how these traces are laid out, I should only have to connect 9 jumper wires to the board. 1 of those 9 wires will break out into 8 wires itself, which will go to one side of the 1st, 4th, 7th, and 10th led's on both rows. The remaining 8 wires connected to the board will connect to the "other" side of the 3rd, 6th, 9th, and 12th led's on both rows. The remaining led wires would connect together depending on where they fall in the arrangement.
                              Last edited by JimBanville; 08-12-2020, 01:27 PM.

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                                #35
                                Re: Strange malfunctioning LED audio peak level meter problem

                                https://www.amazon.com/EDGELEC-Prewi.../dp/B07FN5HVPR

                                Would these work?

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                                  #36
                                  Re: Strange malfunctioning LED audio peak level meter problem

                                  https://www.aliexpress.com/item/32423249665.html
                                  those are great - 5 colours - 20 of each for about $3

                                  Comment


                                    #37
                                    Re: Strange malfunctioning LED audio peak level meter problem

                                    Originally posted by stj View Post
                                    https://www.aliexpress.com/item/32423249665.html
                                    those are great - 5 colours - 20 of each for about $3
                                    So I've killed most of the LED's by now. Those exposed microscopic wires are ridiculous. Trying to use that crappy usb microscope I was dragging it all across that board. Only a couple of the LED's still work. So I measured one at around 1.5v and the next one beside it in the "3 led group" was measured at 3v. I couldn't get a voltage reading on the third one in that "group". Do u think it would have been 1.5v higher or double the one before it?
                                    Last edited by JimBanville; 08-12-2020, 04:22 PM.

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                                      #38
                                      Re: Strange malfunctioning LED audio peak level meter problem

                                      each led takes about 2v so with 3 in series that WORK - each will show the same voltage.
                                      the microscope is not supposed to be that close to the board btw!

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                                        #39
                                        Re: Strange malfunctioning LED audio peak level meter problem

                                        Originally posted by stj View Post
                                        each led takes about 2v so with 3 in series that WORK - each will show the same voltage.
                                        the microscope is not supposed to be that close to the board btw!
                                        Unfortunately that microscope has to be "on" whatever you are looking at when it's set to max magnification.

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                                          #40
                                          Re: Strange malfunctioning LED audio peak level meter problem

                                          After a good cry, I would do the surgery on the old pc board. Get a bunch of 0805 or 0603 LED's (old style yellow green) and scrape off the old ones and some solder mask with an exacto knife. Then some flux and solder on the new LEDs.

                                          There are 12 LED VU meter displays and/or kits that might fit as well, from fleabay or Ali.

                                          edit: the description is too funny:
                                          Display effect:
                                          1. strip show after peak travel whereabouts
                                          2. strip show after the disappearance of the peak travel
                                          3. The strip display (no peak display)
                                          4. strip show right after the peak flow disappears
                                          5. The strip display (three lights)
                                          6. striped marquee display peak effect
                                          7. Peak strip show right jump lamp lights two bits whereabouts
                                          Attached Files
                                          Last edited by redwire; 08-14-2020, 01:54 PM.

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