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Re: [softrock40] Troubleshooting 80/40 RXTX 6.2- Oscillator Circuit

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  • keithlebaron
    Hi Tony, You are correct. It was the collector of Q14 that I should have stated. The voltage on Q13 measures C 4.87v B 2.355 v E 1.770 v 73, Keith, W9KGY
    Message 1 of 4 , Sep 2, 2007
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      Hi Tony,

      You are correct. It was the collector of Q14 that I should have stated.

      The voltage on Q13 measures
      C   4.87v
      B   2.355 v
      E   1.770 v

      73,
      Keith, W9KGY

      Tony Parks wrote:

      Hi Keith,
       
      What DC voltage are you seeing at the base and emitter of Q13?  Also, I think you must mean that the collector of Q14 is at a DC voltage of 2.2 volts since the emitter of Q14 is connected to the +5 volt supply line.
       
      The oscillator signal at the emitter of  Q13 should be much lartger than you are measuring.
       
      73,
      Tony KB9YIG
      ----- Original Message -----
      Sent: Sunday, September 02, 2007 12:43 PM
      Subject: [softrock40] Troubleshooting 80/40 RXTX 6.2- Oscillator Circuit

      All my voltages and resistances check out fine. Nothing happened when I connected it to the sound card. Intuitively, I decided to start at the oscillator circuit.
      At the emitter of Q13 I am measuring about 5 mv Peak toPeak
      At the emitter of Q14 I am measuring about 1 volt Peak to Peak but  is offset 2.2 volts above ground.

      Where to I hit the hammer (or where/what do I do to fix this)?

      I went back through the past files to early July, thinking I had read a post(s) regarding the oscillator circuit but could not find the post.

      73,
      Keith



      No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.13.2/983 - Release Date: 9/1/2007 4:20 PM
    • keithlebaron
      Hi Tony, I ve remeasured some voltages and here are some observations. Q13: 550 mv P-P on emitter Q14: 1 V P-P on collector/ 2.2 volts DC offset U5: Do not
      Message 2 of 4 , Sep 5, 2007
      • 0 Attachment
        Hi Tony,

        I've remeasured some voltages and here are some observations.

        Q13: 550 mv P-P on emitter
        Q14: 1 V P-P on collector/ 2.2 volts DC offset

        U5: Do not understand why I was seeing 4 V P-P on pins 8 and 9.

        Please advise next step.

        73,
        Keith, W9KGY


        keithlebaron wrote:

        Hi Tony,

        You are correct. It was the collector of Q14 that I should have stated.

        The voltage on Q13 measures
        C   4.87v
        B   2.355 v
        E   1.770 v

        73,
        Keith, W9KGY

        Tony Parks wrote:

        Hi Keith,
         
        What DC voltage are you seeing at the base and emitter of Q13?  Also, I think you must mean that the collector of Q14 is at a DC voltage of 2.2 volts since the emitter of Q14 is connected to the +5 volt supply line.
         
        The oscillator signal at the emitter of  Q13 should be much lartger than you are measuring.
         
        73,
        Tony KB9YIG
        ----- Original Message -----
        Sent: Sunday, September 02, 2007 12:43 PM
        Subject: [softrock40] Troubleshooting 80/40 RXTX 6.2- Oscillator Circuit

        All my voltages and resistances check out fine. Nothing happened when I connected it to the sound card. Intuitively, I decided to start at the oscillator circuit.
        At the emitter of Q13 I am measuring about 5 mv Peak toPeak
        At the emitter of Q14 I am measuring about 1 volt Peak to Peak but  is offset 2.2 volts above ground.

        Where to I hit the hammer (or where/what do I do to fix this)?

        I went back through the past files to early July, thinking I had read a post(s) regarding the oscillator circuit but could not find the post.

        73,
        Keith



        No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.13.2/983 - Release Date: 9/1/2007 4:20 PM

        No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.13.2/983 - Release Date: 9/1/2007 4:20 PM
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