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Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))

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  • hans.ringdahl
    Hi all! This building have taken some time, but what do you do with two kids 4,5 years and 1,5 years that take much time... Well, after holding up my building
    Message 1 of 13 , Sep 14, 2012
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      Hi all!

      This building have taken some time, but what do you do with two kids 4,5 years and 1,5 years that take much time...

      Well, after holding up my building I started today at stage 06_RX Mixer (QSD) on my Ensemble RXTX.

      All looking good, BUT I can't get any good values in the test stage.

      I get the following results:
      U10 (FST3253)
      Pin 8 0V
      Pins 1 and 15 (PTT OFF) 47mV
      Pin 2 2.55V
      Pin 14 2.55V
      Pin 7 1.2V should be 2.50???
      Pin 9 1.2V should be 2.50???
      Pin 16 5.1V
      Pin 1 and 15 (PTT ON) 2.2V should be 5.0V ???

      I have looked over and over again on the solderings, I have resolder two times...
      But still get this values!?!?!?

      What have I done wrong???

      All other stages before this gives the right values!

      Thanks for any help on the way!

      //Hans - SA0AZF
    • KF4BQ
      ... Hi Hans, Not clear if all the reading were with PTT OFF (except last line)?? With PTT ON the chip outputs are disabled so the readings will be different.
      Message 2 of 13 , Sep 14, 2012
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        --- In softrock40@yahoogroups.com, "hans.ringdahl" <hans.ringdahl@...> wrote:
        > Well, after holding up my building I started today at stage 06_RX Mixer (QSD) on my Ensemble RXTX.
        >
        > All looking good, BUT I can't get any good values in the test stage.
        >
        > I get the following results:
        > U10 (FST3253)
        > Pin 8 0V
        > Pins 1 and 15 (PTT OFF) 47mV
        > Pin 2 2.55V
        > Pin 14 2.55V
        > Pin 7 1.2V should be 2.50???
        > Pin 9 1.2V should be 2.50???
        > Pin 16 5.1V
        > Pin 1 and 15 (PTT ON) 2.2V should be 5.0V ???
        >
        > I have looked over and over again on the solderings, I have resolder two times...


        Hi Hans,
        Not clear if all the reading were with PTT OFF (except last line)?? With PTT ON the chip outputs are disabled so the readings will be different. If they were with PTT OFF: the 2.5V bias doesn't look like it is feed thru the FST3253. Check the R61/R62 connection; this sets the 2.5V bias. It then feeds thru T5 center tap to R54 and R53; should have 2.5V there too. Then thru U10 (if enabled by p1,15 at 0V).

        Looks like you have a switching problem from the PTT chain. The Pin 1,15 with PTTON should be near 5V. To follow the path with PTTON: Q9 gate (QSD EN) should near 0V. The optocoupler collector U4 (/PTT) should be near 0V too.

        73, Mike Collins KF4BQ
      • Alan
        ... Subject: [softrock40] Problem in stage (Ensemble RXTX 06_RX Mixer (QSD)) ... Hans, Pins 11, 12? R62 hairpin? Are R 53, 54, 61,62 correct values? Just maybe
        Message 3 of 13 , Sep 14, 2012
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          ----- Original Message -----
          Subject: [softrock40] Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))


          > Hi all!
          >
          > This building have taken some time, but what do you do with two kids 4,5 years and 1,5 years that take much time...
          >
          > Well, after holding up my building I started today at stage 06_RX Mixer (QSD) on my Ensemble RXTX.
          >
          > All looking good, BUT I can't get any good values in the test stage.
          >
          > I get the following results:
          > U10 (FST3253)
          > Pin 8 0V
          > Pins 1 and 15 (PTT OFF) 47mV
          > Pin 2 2.55V
          > Pin 14 2.55V
          > Pin 7 1.2V should be 2.50???
          > Pin 9 1.2V should be 2.50???
          > Pin 16 5.1V
          > Pin 1 and 15 (PTT ON) 2.2V should be 5.0V ???
          >

          Hans,

          Pins 11, 12? R62 hairpin?
          Are R 53, 54, 61,62 correct values?
          Just maybe this is a false reading but check above first.


          Pins 1, 15 point to another fault, in the switching circuit. Check this again. Let us know Q3 voltages.

          73 Alan G4ZFQ
        • Alan
          ... Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD)) ... Hans, Before you fit a new regulator check the resistance from R61 hairpin
          Message 4 of 13 , Sep 15, 2012
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            ----- Original Message -----
            Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))


            >5V, hairpin R61 and found that something was very wrong... it just read 1.8V or so...
            > Realised that there could be something with U9 (LM78L05).
            > It was hot and smelled burned... :-(
            > It is nolonger a voltage regulator, it's an EX-voltage regulator...
            > So now I will wait until monday and get a new one - hopefully that will do one of the problems.
            >

            Hans,

            Before you fit a new regulator check the resistance from R61 hairpin to ground.
            If it was hot then there is probably something wrong. A solder splash or faulty component.
            For example, are R60/61 really 1K?

            73 Alan G4ZFQ



            > I also measured some voltages:
            > R62 hairpin (with the faulty voltage regulator) PTT OFF, 0.5V - PTT ON, 0.5V
            >
            > Q3 (2N3906)
            > PTT OFF. PTT ON
            > E 12V. E 12V
            > B 11.3V. B 11.3V
            > C 1.1V. C 12V
            >
            > Q9 (BS170)
            > PTT OFF. PTT ON
            > S 0V. S 0.8V
            > G 6.6V. G 3.3mV
            > D 0V. D 0V
            >
            > I'll be back with new values when I have changed the voltage regulator... ;-)
            >
          • Hans Ringdahl
            Hi Alan and Mike! Got an hour for myself and just checked your surgestions. I checked the point were there should be 5V, hairpin R61 and found that something
            Message 5 of 13 , Sep 15, 2012
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              Hi Alan and Mike!
              Got an hour for myself and just checked your surgestions.
              I checked the point were there should be 5V, hairpin R61 and found that something was very wrong... it just read 1.8V or so...
              Realised that there could be something with U9 (LM78L05).
              It was hot and smelled burned... :-(
              It is nolonger a voltage regulator, it's an EX-voltage regulator...
              So now I will wait until monday and get a new one - hopefully that will do one of the problems.

              I also measured some voltages:
              R62 hairpin (with the faulty voltage regulator) PTT OFF, 0.5V - PTT ON, 0.5V

              Q3 (2N3906)
              PTT OFF. PTT ON
              E 12V. E 12V
              B 11.3V. B 11.3V
              C 1.1V. C 12V

              Q9 (BS170)
              PTT OFF. PTT ON
              S 0V. S 0.8V
              G 6.6V. G 3.3mV
              D 0V. D 0V

              I'll be back with new values when I have changed the voltage regulator... ;-)

              Thanks Hans - SA0AZF
            • Hans Ringdahl
              Hi Alan! Thanks for the help. Resistance from R61 hairpin to GND is 1k28 ohm, don t know what it should read... R61 and R62 are Brown-Black-Black-Brown-Brown,
              Message 6 of 13 , Sep 16, 2012
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                Hi Alan!

                Thanks for the help.
                Resistance from R61 hairpin to GND is 1k28 ohm, don't know what it should read...
                R61 and R62 are Brown-Black-Black-Brown-Brown, BUT they both give the value of 816 ohms!?
                Well if both have the same value (even if it's not within the tolerance of what is marked with) - it would give 2.5V if feed with 5V, in the voltage divider...
                I will check for bad solderings...

                //Hans - SA0AZF
              • Alan
                ... Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD)) ... Hans The resistance shows that there would be about 5mA flowing so there
                Message 7 of 13 , Sep 16, 2012
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                  ----- Original Message -----
                  Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))


                  >> Resistance from R61 hairpin to GND is 1k28 ohm, don't know what it should read...
                  > R61 and R62 are Brown-Black-Black-Brown-Brown, BUT they both give the value of 816 ohms!?

                  Hans

                  The resistance shows that there would be about 5mA flowing so there is nothing directly shorting to ground.
                  Often you will not correctly read resistor values when they are connected, the meter will measure other resistances as well.


                  > Well if both have the same value (even if it's not within the tolerance of what is marked with) - it would give 2.5V if feed with
                  > 5V, in the voltage divider...
                  > I will check for bad solderings...
                  >

                  It is possible you have a faulty IC, or one fitted the wrong way.
                  If you still get low 5V, or the regulator gets hot (check the current) then carefully lift the 5V power pins of the ICs.
                  Start with pin 16 of U10.
                  Use a needle to raise it just above the contact pad.

                  73 Alan G4ZFQ
                • Hans Ringdahl
                  Thank you Alan for all help! I don t know what I would do without your help... I put in a new voltage regulator and now I got 5V were ever I should have 5V...
                  Message 8 of 13 , Sep 17, 2012
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                    Thank you Alan for all help!
                    I don't know what I would do without your help...

                    I put in a new voltage regulator and now I got 5V were ever I should have 5V... and it is not HOT!!!

                    But now I will have a look at Q3, I messured all legs on it with PTT OFF - it gave something like 12V on all of them?????
                    I then shorted leg 4 of the opto-coupler to GND, to simulate PTT ON - and messured Q3, ALL legs still showed 12V?????

                    Something is wrong!?!?
                    Hopefully I wil get time tomorrow to have a look at Q3 and U10...

                    I'll be back...

                    //Hans - SA0AZF
                  • Alan
                    ... Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD)) ... Good! ... Hopefully I wil get time tomorrow to have a look at Q3 and
                    Message 9 of 13 , Sep 17, 2012
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                      ----- Original Message -----
                      Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))


                      >
                      > I put in a new voltage regulator and now I got 5V were ever I should have 5V... and it is not HOT!!!
                      >

                      Good!


                      > But now I will have a look at Q3, I messured all legs on it with PTT OFF - it gave something like 12V on all of them?????
                      > I then shorted leg 4 of the opto-coupler to GND, to simulate PTT ON - and messured Q3, ALL legs still showed 12V?????
                      >
                      Hopefully I wil get time tomorrow to have a look at Q3 and U10...
                      >

                      Hans,

                      Yes, do the tests again and let us know the voltages.

                      73 Alan G4ZFQ
                    • Hans Ringdahl
                      Hi Alan and all of you following this... Well, I had a quick qhange of Q3 and for 2 minutes I got the following values with PTT OFF: E 12V, B 11.5V and C 45mV
                      Message 10 of 13 , Sep 19, 2012
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                        Hi Alan and all of you following this...

                        Well, I had a quick qhange of Q3 and for 2 minutes I got the following values with PTT OFF:
                        E 12V, B 11.5V and C 45mV and the Gate of Q9 were 6.6V...

                        I then wanted to messure one extra time to confirm the values and then E, B and C of Q3 where all 12V???

                        So now I'm back to square one it seems with Q3...?!?!

                        I'll try to get some more timethis evening.

                        //Hans
                      • Alan
                        ... Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD)) ... Hans, That is correct for RX. Q3, PNP, is off. Volts on U10 pins 1, 15
                        Message 11 of 13 , Sep 19, 2012
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                          ----- Original Message -----
                          Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))


                          >
                          > Well, I had a quick qhange of Q3 and for 2 minutes I got the following values with PTT OFF:
                          > E 12V, B 11.5V and C 45mV and the Gate of Q9 were 6.6V...
                          >

                          Hans,

                          That is correct for RX. Q3, PNP, is off.

                          Volts on U10 pins 1, 15 RX?

                          Next check TX values.

                          73 Alan G4ZFQ
                        • hans.ringdahl
                          Thank you Alan for all help... I had some spare time this evening and checked how much current the softrock drains... the multimeter shows 99.6 mA , and that
                          Message 12 of 13 , Sep 21, 2012
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                            Thank you Alan for all help...
                            I had some spare time this evening and checked how much current the softrock drains... the multimeter shows 99.6 mA , and that is without the USB-cable pluged in.

                            This seems way to much... :-(

                            I also think I might have broken the 5 V regulator again.Could it have something to do with the 99.6 mA???

                            Well - I have some checking to do!!!

                            //Hans

                            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                            >
                            >
                            > ----- Original Message -----
                            > Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))
                            >
                            >
                            > >
                            > > Well, I had a quick qhange of Q3 and for 2 minutes I got the following values with PTT OFF:
                            > > E 12V, B 11.5V and C 45mV and the Gate of Q9 were 6.6V...
                            > >
                            >
                            > Hans,
                            >
                            > That is correct for RX. Q3, PNP, is off.
                            >
                            > Volts on U10 pins 1, 15 RX?
                            >
                            > Next check TX values.
                            >
                            > 73 Alan G4ZFQ
                            >
                          • hans.ringdahl
                            Hi Alan and all of you! After a LONG time off, including one week in London to take everyting of my mind about the SoftRock... :-) I changed the U10 FST3253
                            Message 13 of 13 , Oct 16, 2012
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                              Hi Alan and all of you!

                              After a LONG time off, including one week in London to take everyting of my mind about the SoftRock... :-)

                              I changed the U10 FST3253 which I presumed was falty after I solder and unsoldered a few times to much.
                              I also changed the Q3 2N3906 and the U9 LM78L05, who got too hot.

                              Last time I measured the current it was almost 100mA, way to much.

                              After changing the above things everyting is fine, I'm back in line!!!

                              Current is low, less than 10mA and Q3 switches fine when I test PTT in CFGSR. U9 no longer hot.
                              And all values of U10 is happy!

                              And I'm happy again!

                              THANKS Alan!!!



                              --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                              >
                              >
                              > ----- Original Message -----
                              > Subject: [softrock40] Re: Problem in stage (Ensemble RXTX 06_RX Mixer (QSD))
                              >
                              >
                              > >
                              > > Well, I had a quick qhange of Q3 and for 2 minutes I got the following values with PTT OFF:
                              > > E 12V, B 11.5V and C 45mV and the Gate of Q9 were 6.6V...
                              > >
                              >
                              > Hans,
                              >
                              > That is correct for RX. Q3, PNP, is off.
                              >
                              > Volts on U10 pins 1, 15 RX?
                              >
                              > Next check TX values.
                              >
                              > 73 Alan G4ZFQ
                              >
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