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Re: The DIY microphone which unsuccessful

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  • archieaa1
    The most common causes of failure when building a circuit from a proven schematic are A. solder bridges B. parts installed in the incorrect orientation. C.
    Message 1 of 7 , Nov 25, 2012
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      The most common causes of failure when building a circuit from a proven schematic are
      A. solder bridges
      B. parts installed in the incorrect orientation.
      C. misread part numbers or values.
      D. overheated parts

      Solutions

      A. Careful inspection of your work. Scrape off any residual flux.
      B. Double check the leads of the transistors and diode bands are in the correct position. Doubly important with a transistor number that is different. If you reverse the Zeners on the output, no signal.
      C.Double check resistor values with a VOM, preferably a digital one.
      D. Did anything give you grief when soldering?

      Most problem can be found by checking voltages at the transistors collectors and emitters or in the case of the FET, the drain and source

      I hope this helps

      Archie



      --- In micbuilders@yahoogroups.com, "zundamame" <zundamame@...> wrote:
      >
      > Hello.
      > I DIYed the microphone according to the GenChinaMod circuit of Zapnspark.
      > But there is almost no output.
      > According to reading by DMM, DC-DC seemed not to work.
      > It did not find wrong, although I checked the circuit again and again.
      > I used not "BC559C" but "BC559CTA."
      > And, L2 used the inductor of 68uh (62uh was not able to be got).
      > What is the mistake which may happen most?
      >
    • archieaa1
      ... After digging a little further here s what I ve found. From what I could find out, It looks like the BC559CTA is the ROHS (Reduction Of Hazardous
      Message 2 of 7 , Nov 26, 2012
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        --- In micbuilders@yahoogroups.com, "archieaa1" <archieaa@...> wrote:
        >
        >
        >
        >
        >
        >
        > The most common causes of failure when building a circuit from a proven schematic are
        > A. solder bridges
        > B. parts installed in the incorrect orientation.
        > C. misread part numbers or values.
        > D. overheated parts
        >
        > Solutions
        >
        > A. Careful inspection of your work. Scrape off any residual flux.
        > B. Double check the leads of the transistors and diode bands are in the correct position. Doubly important with a transistor number that is different. If you reverse the Zeners on the output, no signal.
        > C.Double check resistor values with a VOM, preferably a digital one.
        > D. Did anything give you grief when soldering?
        >
        > Most problem can be found by checking voltages at the transistors collectors and emitters or in the case of the FET, the drain and source
        >
        > I hope this helps
        >
        > Archie
        >
        >
        >
        > --- In micbuilders@yahoogroups.com, "zundamame" <zundamame@> wrote:
        > >
        > > Hello.
        > > I DIYed the microphone according to the GenChinaMod circuit of Zapnspark.
        > > But there is almost no output.
        > > According to reading by DMM, DC-DC seemed not to work.
        > > It did not find wrong, although I checked the circuit again and again.
        > > I used not "BC559C" but "BC559CTA."
        > > And, L2 used the inductor of 68uh (62uh was not able to be got).
        > > What is the mistake which may happen most?
        > >
        >

        After digging a little further here's what I've found. From what I could find out, It looks like the BC559CTA is the ROHS (Reduction Of Hazardous Substances) version of the of the BC559C. It short it's the same thing with out using Lead. Using a 68uH in place of a 62uH could be problematic. Changing the value of L2 will at very least change the frequency of the oscillator in the DC to DC converter. At worst it might prevent the oscillator from starting. That said it is with in 10% of the original value so, It should work. Do you have access to an oscilloscope? I would start by disconnecting the Dc to Dc converter from the capsule and test for voltage output just to be certain that something isn't loading down the DC to DC converter. I would also encourage you to take a look at GenChinaPolCirc.pdf from zaps folder. It gives you some voltages to look for. An oscilloscope would let see if the oscillator was starting.

        Certainly If you have no polarizing voltage you will have almost no output. You could try polarizing the capsule like the scheme used in the Alice circuit. It will be lower voltage so lower output but, sometimes simple is better. You are using a 2N5551 transistor for the DC to DC I trust.

        I hope this helps

        Archie
      • zundamame
        Hello, Archie, Thank you for the reply. I need to do A to D which you proposed. And also I do not have an oscilloscope. I am using 2N5551 transistor for a
        Message 3 of 7 , Nov 27, 2012
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          Hello, Archie,
          Thank you for the reply.

          I need to do A to D which you proposed.
          And also I do not have an oscilloscope.
          I am using 2N5551 transistor for a DC-DC converter.
        • zundamame
          There were two mistakes. The resistance which should be 750k ohms was 750 ohms. Pinpout of J305 of Calogic which I have was S-D-G. My DIY microphone works now.
          Message 4 of 7 , Dec 1, 2012
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            There were two mistakes.
            The resistance which should be 750k ohms was 750 ohms.
            Pinpout of J305 of Calogic which I have was S-D-G.

            My DIY microphone works now.
            Thank you, Archie.
          • archieaa1
            You are very welcome. Glad to hear it s working. Archie
            Message 5 of 7 , Dec 1, 2012
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              You are very welcome. Glad to hear it's working.

              Archie



              --- In micbuilders@yahoogroups.com, "zundamame" <zundamame@...> wrote:
              >
              > There were two mistakes.
              > The resistance which should be 750k ohms was 750 ohms.
              > Pinpout of J305 of Calogic which I have was S-D-G.
              >
              > My DIY microphone works now.
              > Thank you, Archie.
              >
            • zundamame
              I am sorry that my post gives misunderstanding. My knowledge was insufficient. The result is equal even if it connects Dorain and Source reverse in FET.
              Message 6 of 7 , Dec 1, 2012
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                I am sorry that my post gives misunderstanding.
                My knowledge was insufficient.
                The result is equal even if it connects Dorain and Source reverse in FET.
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