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Re: no sidetone on ATS-3B.1 initial bringup

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  • scottg720
    After probing around a bit with my oscope I discovered that after shorting pin 4 (gnd) on U3 directly to ground not only do I hear the sidetone 8 come
    Message 1 of 4 , Sep 16 4:17 PM
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      After probing around a bit with my oscope I discovered that after shorting pin 4 (gnd) on U3 directly to ground not only do I hear the sidetone '8' come through the headphones, I also hear what sounds like normal receiver hiss.

      I've touched up the pin 4 solder joint a few times now but this doesn't seem to help.

      Thoughts on this situation?

      tnx and 73,
      Scott



      --- In AT_Sprint@yahoogroups.com, "scottg720" <k1oa@...> wrote:
      >
      > I'm going through the initial bringup of an ATS-3B.1 main
      > board and not hearing the sidetone '8' come through the speaker.
      > I looked back through the archives and found
      >
      > http://groups.yahoo.com/group/AT_Sprint/message/4024
      >
      > which was very helpful. I think I've been through all
      > suggested in this thread, but may have missed something.
      >
      > It appears that the sidetone is being generated and not
      > making it through the audio section (?).
      >
      >
      > Observations with my board:
      >
      > 1. on power up I hear a quick popping noise followed
      > by a short burst of white noise, followed by an 8
      > on the LED display, after which the LED goes blank
      >
      > 2. The 5V and 3.5V regulators are working OK
      >
      > 3. TP1 reads 0V, R19 on the side away from TP1 reads 0V
      >
      > 4. There are no observable bridges on any ICs
      >
      > 5. On power up my scope shows an audio square wave coming out of
      > pin 3 of U8 and it blinks an '8' in code! It also shows a lower
      > amplitude wave form on pin 3 of U4 blinking '8', although it
      > doesn't look like a square wave.
      >
      > 6. on U8 I have 5V on pins 2, 4, 10, 12, 14 and 0V on all others
      >
      > 7. U7 voltages are 1:1.2, 2:1.2, 3:3.5, 4:5.0, 5:3.5, 6:2.5, 7:0
      > 8:1.7, 9:0, 10:0, 11:0, 12:0, 13:0, 14:3.5, 15:3.5, 16:0, 17:0.4,
      > 18:0, 19:0.4, 20: 0.8
      >
      > 8. U3 voltages are 5V on all but pin 4 which is 0V. Voltage table in the manual says only P8 should read 5V. Is this part of the problem?
      >
      > 9. U4 voltages are 1:5.0, 2:0, 3:floating, 4:5.0, 5:5.0, 6:3.5. Table
      > says P1 and P4 should be 2.2V, problem?
      >
      > 10. All ICs are oriented properly.
      >
      >
      > Actions taken:
      >
      > 1. touched up solder connections for U4, U5, U7 and U8, all components
      > that touch U3 and U4
      >
      > 2. touched up solder connections for audio connector
      >
      >
      > Ideas?
      >
      > tnx and 73,
      > Scott, K1OA
      >
    • Dale Putnam
      Can you measure the resistance to ground from that pin? It may need to be connected to ground? Even tho the pin is supposed to be grounded on the board, maybe
      Message 2 of 4 , Sep 16 4:50 PM
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        Can you measure the resistance to ground from that pin? It may need to be connected to ground? Even tho the pin is supposed to be grounded on the board, maybe the holethrough plating has come loose, or not gotten installed correctly and there isn't a ground on it.

        --... ...-- Dale - WC7S in Wy
         

        To: AT_Sprint@yahoogroups.com
        From: k1oa@...
        Date: Sun, 16 Sep 2012 23:17:30 +0000
        Subject: [AT_Sprint] Re: no sidetone on ATS-3B.1 initial bringup

         


        After probing around a bit with my oscope I discovered that after shorting pin 4 (gnd) on U3 directly to ground not only do I hear the sidetone '8' come through the headphones, I also hear what sounds like normal receiver hiss.

        I've touched up the pin 4 solder joint a few times now but this doesn't seem to help.

        Thoughts on this situation?

        tnx and 73,
        Scott

        --- In AT_Sprint@yahoogroups.com, "scottg720" <k1oa@...> wrote:
        >
        > I'm going through the initial bringup of an ATS-3B.1 main
        > board and not hearing the sidetone '8' come through the speaker.
        > I looked back through the archives and found
        >
        > http://groups.yahoo.com/group/AT_Sprint/message/4024
        >
        > which was very helpful. I think I've been through all
        > suggested in this thread, but may have missed something.
        >
        > It appears that the sidetone is being generated and not
        > making it through the audio section (?).
        >
        >
        > Observations with my board:
        >
        > 1. on power up I hear a quick popping noise followed
        > by a short burst of white noise, followed by an 8
        > on the LED display, after which the LED goes blank
        >
        > 2. The 5V and 3.5V regulators are working OK
        >
        > 3. TP1 reads 0V, R19 on the side away from TP1 reads 0V
        >
        > 4. There are no observable bridges on any ICs
        >
        > 5. On power up my scope shows an audio square wave coming out of
        > pin 3 of U8 and it blinks an '8' in code! It also shows a lower
        > amplitude wave form on pin 3 of U4 blinking '8', although it
        > doesn't look like a square wave.
        >
        > 6. on U8 I have 5V on pins 2, 4, 10, 12, 14 and 0V on all others
        >
        > 7. U7 voltages are 1:1.2, 2:1.2, 3:3.5, 4:5.0, 5:3.5, 6:2.5, 7:0
        > 8:1.7, 9:0, 10:0, 11:0, 12:0, 13:0, 14:3.5, 15:3.5, 16:0, 17:0.4,
        > 18:0, 19:0.4, 20: 0.8
        >
        > 8. U3 voltages are 5V on all but pin 4 which is 0V. Voltage table in the manual says only P8 should read 5V. Is this part of the problem?
        >
        > 9. U4 voltages are 1:5.0, 2:0, 3:floating, 4:5.0, 5:5.0, 6:3.5. Table
        > says P1 and P4 should be 2.2V, problem?
        >
        > 10. All ICs are oriented properly.
        >
        >
        > Actions taken:
        >
        > 1. touched up solder connections for U4, U5, U7 and U8, all components
        > that touch U3 and U4
        >
        > 2. touched up solder connections for audio connector
        >
        >
        > Ideas?
        >
        > tnx and 73,
        > Scott, K1OA
        >


      • scottg720
        Turned out to be a bad solder joint on R7 which explains the 5V (and not 2.5V) bias I was seeing on U3. Thanks for the reply Dale. 73, Scott
        Message 3 of 4 , Sep 17 5:09 PM
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          Turned out to be a bad solder joint on R7 which explains the 5V (and not 2.5V) bias I was seeing on U3.

          Thanks for the reply Dale.

          73,
          Scott


          --- In AT_Sprint@yahoogroups.com, Dale Putnam <daleputnam@...> wrote:
          >
          >
          > Can you measure the resistance to ground from that pin? It may need to be connected to ground? Even tho the pin is supposed to be grounded on the board, maybe the holethrough plating has come loose, or not gotten installed correctly and there isn't a ground on it.
          >
          > --... ...--
          > Dale - WC7S in Wy
          > To: AT_Sprint@yahoogroups.com
          > From: k1oa@...
          > Date: Sun, 16 Sep 2012 23:17:30 +0000
          > Subject: [AT_Sprint] Re: no sidetone on ATS-3B.1 initial bringup
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
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          >
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          >
          >
          >
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          >
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          >
          >
          >
          >
          >
          > After probing around a bit with my oscope I discovered that after shorting pin 4 (gnd) on U3 directly to ground not only do I hear the sidetone '8' come through the headphones, I also hear what sounds like normal receiver hiss.
          >
          >
          >
          > I've touched up the pin 4 solder joint a few times now but this doesn't seem to help.
          >
          >
          >
          > Thoughts on this situation?
          >
          >
          >
          > tnx and 73,
          >
          > Scott
          >
          >
          >
          > --- In AT_Sprint@yahoogroups.com, "scottg720" <k1oa@> wrote:
          >
          > >
          >
          > > I'm going through the initial bringup of an ATS-3B.1 main
          >
          > > board and not hearing the sidetone '8' come through the speaker.
          >
          > > I looked back through the archives and found
          >
          > >
          >
          > > http://groups.yahoo.com/group/AT_Sprint/message/4024
          >
          > >
          >
          > > which was very helpful. I think I've been through all
          >
          > > suggested in this thread, but may have missed something.
          >
          > >
          >
          > > It appears that the sidetone is being generated and not
          >
          > > making it through the audio section (?).
          >
          > >
          >
          > >
          >
          > > Observations with my board:
          >
          > >
          >
          > > 1. on power up I hear a quick popping noise followed
          >
          > > by a short burst of white noise, followed by an 8
          >
          > > on the LED display, after which the LED goes blank
          >
          > >
          >
          > > 2. The 5V and 3.5V regulators are working OK
          >
          > >
          >
          > > 3. TP1 reads 0V, R19 on the side away from TP1 reads 0V
          >
          > >
          >
          > > 4. There are no observable bridges on any ICs
          >
          > >
          >
          > > 5. On power up my scope shows an audio square wave coming out of
          >
          > > pin 3 of U8 and it blinks an '8' in code! It also shows a lower
          >
          > > amplitude wave form on pin 3 of U4 blinking '8', although it
          >
          > > doesn't look like a square wave.
          >
          > >
          >
          > > 6. on U8 I have 5V on pins 2, 4, 10, 12, 14 and 0V on all others
          >
          > >
          >
          > > 7. U7 voltages are 1:1.2, 2:1.2, 3:3.5, 4:5.0, 5:3.5, 6:2.5, 7:0
          >
          > > 8:1.7, 9:0, 10:0, 11:0, 12:0, 13:0, 14:3.5, 15:3.5, 16:0, 17:0.4,
          >
          > > 18:0, 19:0.4, 20: 0.8
          >
          > >
          >
          > > 8. U3 voltages are 5V on all but pin 4 which is 0V. Voltage table in the manual says only P8 should read 5V. Is this part of the problem?
          >
          > >
          >
          > > 9. U4 voltages are 1:5.0, 2:0, 3:floating, 4:5.0, 5:5.0, 6:3.5. Table
          >
          > > says P1 and P4 should be 2.2V, problem?
          >
          > >
          >
          > > 10. All ICs are oriented properly.
          >
          > >
          >
          > >
          >
          > > Actions taken:
          >
          > >
          >
          > > 1. touched up solder connections for U4, U5, U7 and U8, all components
          >
          > > that touch U3 and U4
          >
          > >
          >
          > > 2. touched up solder connections for audio connector
          >
          > >
          >
          > >
          >
          > > Ideas?
          >
          > >
          >
          > > tnx and 73,
          >
          > > Scott, K1OA
          >
          > >
          >
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