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Re: RXTX Ensemble U10 Failure

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  • warrenallgyer
    Jim The signal out on Pins 7 and 9 will be just about the same level as the RF signal in. So, unless you are putting a very high level signal into the antenna,
    Message 1 of 6 , Mar 6 8:41 PM
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      Jim

      The signal out on Pins 7 and 9 will be just about the same level as the RF signal in. So, unless you are putting a very high level signal into the antenna, you won't see much here.

      One good trick to see something is if you have an MFJ antenna analyzer or the like, then input it directly to the antenna connector. As you tune the MFJ within 20 KHz of the LO frequency you should see a good level audio signal coming out of Pins 7 and 9. Around 100 mv peak to peak if memory serves.

      Warren Allgyer - W8TOD

      --- In softrock40@yahoogroups.com, "Triton" <kb7skb@...> wrote:
      >
      > I have installed U10 on the board and during the testing phase, can't get the QSD signal out on pins 7/9. When the PTT is activated, I get the proper voltage on pins 1/15 (5 volts). I have confirmed that the supply and ground voltages are good. I confirmed no shorts(solder bridges)between any of the pins.
      >
      > Pin 1 = 0
      > Pin 15 = 0
      > pin 7 = 0
      > pin 9 = .24 v
      > pin 14 = 2.5 v
      > Pin 2 = 2.5 v
      > Pin 8 = 0
      > pin 16 = 5 v
      >
      > I suspect a bad mixer. Anything else I should look at before I buy a new one?
      >
      > Thanks for your help!
      >
      > Jim
      >
    • Alan
      ... Subject: [softrock40] RXTX Ensemble U10 Failure ... Jim, With pins 7 & 9 low it could be U10 but look again for bad joints or solder splashes first.
      Message 2 of 6 , Mar 6 10:55 PM
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        ----- Original Message -----
        Subject: [softrock40] RXTX Ensemble U10 Failure


        >I have installed U10 on the board and during the testing phase, can't get the QSD signal out on pins 7/9. When the PTT is
        >activated, I get the proper voltage on pins 1/15 (5 volts). I have confirmed that the supply and ground voltages are good. I
        >confirmed no shorts(solder bridges)between any of the pins.
        >
        > Pin 1 = 0
        > Pin 15 = 0
        > pin 7 = 0
        > pin 9 = .24 v
        > pin 14 = 2.5 v
        > Pin 2 = 2.5 v
        > Pin 8 = 0
        > pin 16 = 5 v
        >

        Jim,

        With pins 7 & 9 low it could be U10 but look again for bad joints or solder splashes first. Measure the resistance to ground at pins
        7& 9.
        I presume you are testing without PTT activated?

        73 Alan G4ZFQ
      • Triton
        Thanks for your reply.. Shouldn t I expect to see roughly 2.5v on pins 7/9 in RX mode? Thanks, Jim - kb7skb
        Message 3 of 6 , Mar 7 4:54 AM
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          Thanks for your reply..

          Shouldn't I expect to see roughly 2.5v on pins 7/9 in RX mode?

          Thanks,

          Jim - kb7skb

          --- In softrock40@yahoogroups.com, "warrenallgyer" <allgyer@...> wrote:
          >
          > Jim
          >
          > The signal out on Pins 7 and 9 will be just about the same level as the RF signal in. So, unless you are putting a very high level signal into the antenna, you won't see much here.
          >
          > One good trick to see something is if you have an MFJ antenna analyzer or the like, then input it directly to the antenna connector. As you tune the MFJ within 20 KHz of the LO frequency you should see a good level audio signal coming out of Pins 7 and 9. Around 100 mv peak to peak if memory serves.
          >
          > Warren Allgyer - W8TOD
          >
          > --- In softrock40@yahoogroups.com, "Triton" <kb7skb@> wrote:
          > >
          > > I have installed U10 on the board and during the testing phase, can't get the QSD signal out on pins 7/9. When the PTT is activated, I get the proper voltage on pins 1/15 (5 volts). I have confirmed that the supply and ground voltages are good. I confirmed no shorts(solder bridges)between any of the pins.
          > >
          > > Pin 1 = 0
          > > Pin 15 = 0
          > > pin 7 = 0
          > > pin 9 = .24 v
          > > pin 14 = 2.5 v
          > > Pin 2 = 2.5 v
          > > Pin 8 = 0
          > > pin 16 = 5 v
          > >
          > > I suspect a bad mixer. Anything else I should look at before I buy a new one?
          > >
          > > Thanks for your help!
          > >
          > > Jim
          > >
          >
        • Triton
          PTT disabled - I just checked pin 7/9 to ground and it appears pin 7 is shorted to pin 8. I ll remove and reinstall U10. Maybe too much solder paste under the
          Message 4 of 6 , Mar 7 5:08 AM
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            PTT disabled -

            I just checked pin 7/9 to ground and it appears pin 7 is shorted to pin 8.

            I'll remove and reinstall U10. Maybe too much solder paste under the chip.

            Thanks Alan...

            Jim - kb7skb

            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
            >
            >
            > ----- Original Message -----
            > Subject: [softrock40] RXTX Ensemble U10 Failure
            >
            >
            > >I have installed U10 on the board and during the testing phase, can't get the QSD signal out on pins 7/9. When the PTT is
            > >activated, I get the proper voltage on pins 1/15 (5 volts). I have confirmed that the supply and ground voltages are good. I
            > >confirmed no shorts(solder bridges)between any of the pins.
            > >
            > > Pin 1 = 0
            > > Pin 15 = 0
            > > pin 7 = 0
            > > pin 9 = .24 v
            > > pin 14 = 2.5 v
            > > Pin 2 = 2.5 v
            > > Pin 8 = 0
            > > pin 16 = 5 v
            > >
            >
            > Jim,
            >
            > With pins 7 & 9 low it could be U10 but look again for bad joints or solder splashes first. Measure the resistance to ground at pins
            > 7& 9.
            > I presume you are testing without PTT activated?
            >
            > 73 Alan G4ZFQ
            >
          • warrenallgyer
            Robby s documentation clearly calls for 2.5 volts on pins 7 and 9. Having the luxury of a scope, I have never done DC testing in this area but it would appear
            Message 5 of 6 , Mar 7 5:27 AM
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              Robby's documentation clearly calls for 2.5 volts on pins 7 and 9. Having the luxury of a scope, I have never done DC testing in this area but it would appear that not having 2.5 volts would indicate a failure somewhere.

              Warren Allgyer - W8TOD

              --- In softrock40@yahoogroups.com, "Triton" <kb7skb@...> wrote:
              >
              > Thanks for your reply..
              >
              > Shouldn't I expect to see roughly 2.5v on pins 7/9 in RX mode?
              >
              > Thanks,
              >
              > Jim - kb7skb
              >
              > --- In softrock40@yahoogroups.com, "warrenallgyer" <allgyer@> wrote:
              > >
              > > Jim
              > >
              > > The signal out on Pins 7 and 9 will be just about the same level as the RF signal in. So, unless you are putting a very high level signal into the antenna, you won't see much here.
              > >
              > > One good trick to see something is if you have an MFJ antenna analyzer or the like, then input it directly to the antenna connector. As you tune the MFJ within 20 KHz of the LO frequency you should see a good level audio signal coming out of Pins 7 and 9. Around 100 mv peak to peak if memory serves.
              > >
              > > Warren Allgyer - W8TOD
              > >
              > > --- In softrock40@yahoogroups.com, "Triton" <kb7skb@> wrote:
              > > >
              > > > I have installed U10 on the board and during the testing phase, can't get the QSD signal out on pins 7/9. When the PTT is activated, I get the proper voltage on pins 1/15 (5 volts). I have confirmed that the supply and ground voltages are good. I confirmed no shorts(solder bridges)between any of the pins.
              > > >
              > > > Pin 1 = 0
              > > > Pin 15 = 0
              > > > pin 7 = 0
              > > > pin 9 = .24 v
              > > > pin 14 = 2.5 v
              > > > Pin 2 = 2.5 v
              > > > Pin 8 = 0
              > > > pin 16 = 5 v
              > > >
              > > > I suspect a bad mixer. Anything else I should look at before I buy a new one?
              > > >
              > > > Thanks for your help!
              > > >
              > > > Jim
              > > >
              > >
              >
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