Loading ...
Sorry, an error occurred while loading the content.

Re: Bad chip?

Expand Messages
  • wfahle
    Well NOW it s the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces
    Message 1 of 28 , Oct 31, 2012
    • 0 Attachment
      Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):
      http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf

      --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
      >
      > Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at 10k as it should, but with it pulled there is very little voltage at pin 2. The current, since I can now measure it, across R16 is .24mA. The votage at pin 7 doesn't change either; it's still almost zero. The others besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had been reading. I guess R16 becomes part of a voltage divider under the circumstances; I don't understand circuits this complex. So I will try to unseat U6 and see if there is a solder bridge under it from 1 to 8 or something (they are across from each other).
      >
      > --- In softrock40@yahoogroups.com, "Alan" <alan4alan@> wrote:
      > >
      > >
      > > ----- Original Message -----
      > > Subject: [softrock40] Re: Bad chip?
      > >
      > >
      > > > On R50 Hairpin (the standard regular ground reference from the power supply stage).
      > > >
      > >
      > > Right, maybe the voltage is coming through the mixer with some sort of diode action.
      > >
      > >
      > > >> > Everything checks out fine except for 2 voltages. Pin 1 of U6 is reading 5 volts instead of 2.5,
      > >
      > > This could be the IC, but look for a possible PCB fault, a whisker shorting to 5V.
      > > But presumably pins 2,3 are 2V5? Why is 5V not sent to pin 2 via R16? Check R16 and soldering.
      > >
      > > 73 Alan G4ZFQ
      > >
      > >
      > >
      > > and pin 7 of that same chip is
      > > >> > reading near 0, instead of 2.5. This is unbridged, with or without the USB connected, with power.
      > > >> >
      > > >> > It has passed all prior tests, including receiving a signal in CW over the air. I have continuity-tested every pin of both
      > > >> > chips
      > > >> > U6 and U7 to make sure each pin connects to each solder joint, and I have checked that no pin shorts to any other pin, except
      > > >> > pin
      > > >> > 3 to pin 5 on both chips, as they should. Pin 1 to Pin 6 shows 10k resistance, as it should, on both chips. I have
      > > >> > double-checked
      > > >> > the value of every resistor in the TX circuit. I even pulled R21 to do a direct measure because it was reading about half its
      > > >> > actual value plugged in. Pulled it read 2.21k as expected. Pin 1 and 7 of U7 both read correct values of 2.5 volts. So my
      > > >> > question
      > > >> > is, do I have a bad chip? Something else I can check?
      > > >> >
      > > >> > The voltage to R23 hairpin is 2.5, as is R15 and R16, R24, R22, R21, R20, R19 and R18. Only R17 reads 5 volts. I can't see how
      > > >> > it
      > > >> > is coming anywhere but from the chip.
      > > >> >
      > > >> > R25 is -1.2, R26 is 2.5, R27 is 2.5, and R28 is 1.6. The weirdest one there is R25, so I checked the other side of it and it
      > > >> > reads -.9. The last chip is uninstalled at this point, but I'm not sure where the negative voltage is coming from.
      > > >> >
      > > >> >
      > > >>
      > > >> Where have you got the meter negative clip?
      > > >>
      > > >> 73 Alan G4ZFQ
      > > >>
      > > >
      > > >
      > > >
      > > >
      > > > ------------------------------------
      > > >
      > > > Yahoo! Groups Links
      > > >
      > > >
      > > >
      > >
      >
    • MICHAEL TALLENT
      You really want a low noise op-amp for this application as it will determine the noise floor of your receiver. The data sheet you linked looks like nothing
      Message 2 of 28 , Oct 31, 2012
      • 0 Attachment
        You really want a low noise op-amp for this application as it will determine
        the noise floor of your receiver. The data sheet you linked looks like
        nothing special, so you will not get the performance that these receivers
        are capable of.

        Mike T W6MXV

        ----- Original Message -----
        From: "wfahle" <billfahle@...>
        To: <softrock40@yahoogroups.com>
        Sent: Wednesday, October 31, 2012 12:31 PM
        Subject: [softrock40] Re: Bad chip?


        > Well NOW it's the chip for sure. In an attempt to remove the IC to check
        > voltages and such, the green covering began to burn through exposing the
        > copper traces beneath. So I got out the clippers and clipped it loose from
        > the board, so that I could remove each lead individually. This worked, but
        > it tore up some of the pads in the process. I intend to replace it with
        > this chip because it is available locally (and I don't think going SMT
        > again is going to make life any easier):
        > http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf
        >
        > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
        >>
        >> Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at 10k
        >> as it should, but with it pulled there is very little voltage at pin 2.
        >> The current, since I can now measure it, across R16 is .24mA. The votage
        >> at pin 7 doesn't change either; it's still almost zero. The others
        >> besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had
        >> been reading. I guess R16 becomes part of a voltage divider under the
        >> circumstances; I don't understand circuits this complex. So I will try to
        >> unseat U6 and see if there is a solder bridge under it from 1 to 8 or
        >> something (they are across from each other).
      • warrenallgyer
        Bill I feel your pain.... been there, done that... more than once in fact. A trick that will not help you now but may in the future: When removing multi-pin
        Message 3 of 28 , Oct 31, 2012
        • 0 Attachment
          Bill

          I feel your pain.... been there, done that... more than once in fact.

          A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.

          After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.

          Good luck to you.

          Warren Allgyer - W8TOD

          --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
          >
          > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):
        • Patrick Hall
          Interesting technique.    What I do is to remove as much solder as I can with solder wick, then hold the chip with pliers while I blast it with a heat gun. 
          Message 4 of 28 , Oct 31, 2012
          • 0 Attachment
            Interesting technique. 
             
            What I do is to remove as much solder as I can with solder wick, then hold the chip with pliers while I blast it with a heat gun.  After a minute or so the chip will gently lift off with no bent leads and no lifted pads.  Easy - if you have a heat gun that will go high enough to melt solder. 
             
            Patrick KF7UJM

            From: warrenallgyer <allgyer@...>
            To: softrock40@yahoogroups.com
            Sent: Wednesday, October 31, 2012 4:16 PM
            Subject: [softrock40] Re: Bad chip?
             
            Bill

            I feel your pain.... been there, done that... more than once in fact.

            A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.

            After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.

            Good luck to you.

            Warren Allgyer - W8TOD

            --- In mailto:softrock40%40yahoogroups.com, "wfahle" <billfahle@...> wrote:
            >
            > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):

          • Lawrence Galea
            Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a
            Message 5 of 28 , Nov 1, 2012
            • 0 Attachment
              Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a suitable solder pad near one side of the chip, then heat the pins one by one starting from the one farthest away from where you soldered the wire to the solder pad and when the solder melts pull the wire under the pin. This will push up the pin from the pcb. Do all the pins on one side and them to the other side.
              Regards
              Lawrence
                                            Chip pins
                                                   ----------------
               Solder pad  0-------------------------------------------------------Wire
                                                   |                      |
                                                       Chip
                                                   ----------------

              Hope this explains.
              0 is solder pad where wire is soldered
              First heat the pin from the right hand side on the diagram and when solder melts pull the wire under the pin to the top of the page in this diagram and move towards the left pin by pin.
              Then do the same to the other side.

              Da: warrenallgyer <allgyer@...>
              A: softrock40@yahoogroups.com
              Inviato: Giovedì 1 Novembre 2012 0:16
              Oggetto: [softrock40] Re: Bad chip?

               
              Bill

              I feel your pain.... been there, done that... more than once in fact.

              A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.

              After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.

              Good luck to you.

              Warren Allgyer - W8TOD

              --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
              >
              > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):



            • Lawrence Galea
              ps. by the way, some problems are caused by not having high enough heat and having to keep the soldering iron too long on the pcb or a soldering iron which is
              Message 6 of 28 , Nov 1, 2012
              • 0 Attachment
                ps.
                by the way, some problems are caused by not having high enough heat and having to keep the soldering iron too long on the pcb or a soldering iron which is not big enough to heat a big soldering pad especially when a chip or other component is already soldered or when a chip has a tab which has to be soldered to the pcb. When soldering a tab to the pcb, a 100W soldering gun will make the job much quicker and easier with less chance of damage to the pcb and the component than a soldering iron with a very fine tip as the time needed with the gun will be just a second or two while it will take much longer with a small fine-tipped iron. This is apart form the soldering being much easier and neater
                Hope this helps.
                Regards
                Lawrence




                Da: Lawrence Galea <galea_lawrence@...>
                A: "softrock40@yahoogroups.com" <softrock40@yahoogroups.com>
                Inviato: Giovedì 1 Novembre 2012 8:34
                Oggetto: Re: [softrock40] Re: Bad chip?

                 
                Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a suitable solder pad near one side of the chip, then heat the pins one by one starting from the one farthest away from where you soldered the wire to the solder pad and when the solder melts pull the wire under the pin. This will push up the pin from the pcb. Do all the pins on one side and them to the other side.
                Regards
                Lawrence
                                              Chip pins
                                                     ----------------
                 Solder pad  0-------------------------------------------------------Wire
                                                     |                      |
                                                         Chip
                                                     ----------------

                Hope this explains.
                0 is solder pad where wire is soldered
                First heat the pin from the right hand side on the diagram and when solder melts pull the wire under the pin to the top of the page in this diagram and move towards the left pin by pin.
                Then do the same to the other side.

                Da: warrenallgyer <allgyer@...>
                A: softrock40@yahoogroups.com
                Inviato: Giovedì 1 Novembre 2012 0:16
                Oggetto: [softrock40] Re: Bad chip?

                 
                Bill

                I feel your pain.... been there, done that... more than once in fact.

                A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.

                After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.

                Good luck to you.

                Warren Allgyer - W8TOD

                --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
                >
                > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):





              • John
                Yes thats what I do, works very well. I use fine enamelled copper wire, the type that you have to scrape the enamel off of not the type where the enamel comes
                Message 7 of 28 , Nov 1, 2012
                • 0 Attachment
                  Yes thats what I do, works very well.  I use fine enamelled copper wire, the type that you have to scrape the enamel off of not the type where the enamel comes off with heat.
                   
                  For removing the Si570 I use a heat gun.
                   
                  John G3UGY   
                   

                  Sent: Thursday, November 01, 2012 7:34 AM
                  Subject: Re: [softrock40] Re: Bad chip?

                   

                  Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a suitable solder pad near one side of the chip, then heat the pins one by one starting from the one farthest away from where you soldered the wire to the solder pad and when the solder melts pull the wire under the pin. This will push up the pin from the pcb. Do all the pins on one side and them to the other side.
                  Regards
                  Lawrence
                • wfahle
                  Good to know. In other news, the unit is no longer kerchunking when connected to USB. I mentioned elsewhere that I was able to receive a garbled SSB signal and
                  Message 8 of 28 , Nov 1, 2012
                  • 0 Attachment
                    Good to know. In other news, the unit is no longer kerchunking when connected to USB. I mentioned elsewhere that I was able to receive a garbled SSB signal and an intelligible CW signal with a hallway dipole after completing the receiver stage of the build, but now it no longer responds to the computer at all. So this one is bricked; I must have discharged static into it at some point, explaining the other chip failure too.

                    I am off to order another kit and a wrist strap/static mat. I hadn't been taking any particular precautions with regard to static, and having successfully built through the receiver stage I got complacent. I was building in a carpeted room with a non-grounded solder station (http://www.frys.com/product/4825200?source=googleps&gclid=CLqxhPPlrbMCFZGPPAodRz4ASQ) and touching the leads with reckless abandon, so lesson learned there. I think it was the fuzzy slippers and the tesla coil that finally did me in.

                    By the way, I don't consider this build a failure because of all I learned along the way. The next build will go much faster and be cleaner and better. I was never happy with the way I left some of the power supply capacitors floating 1/8" off the board now that I know how to avoid it, so that would have bugged me through the life of the radio. I also put a resistor in upside down (affecting only readability of the part), which admittedly is a small thing compared with a dead USB controller and a noisy radio.

                    Bill K5WL

                    --- In softrock40@yahoogroups.com, "MICHAEL TALLENT" <mwtallent@...> wrote:
                    >
                    > You really want a low noise op-amp for this application as it will determine
                    > the noise floor of your receiver. The data sheet you linked looks like
                    > nothing special, so you will not get the performance that these receivers
                    > are capable of.
                    >
                    > Mike T W6MXV
                    >
                    > ----- Original Message -----
                    > From: "wfahle" <billfahle@...>
                    > To: <softrock40@yahoogroups.com>
                    > Sent: Wednesday, October 31, 2012 12:31 PM
                    > Subject: [softrock40] Re: Bad chip?
                    >
                    >
                    > > Well NOW it's the chip for sure. In an attempt to remove the IC to check
                    > > voltages and such, the green covering began to burn through exposing the
                    > > copper traces beneath. So I got out the clippers and clipped it loose from
                    > > the board, so that I could remove each lead individually. This worked, but
                    > > it tore up some of the pads in the process. I intend to replace it with
                    > > this chip because it is available locally (and I don't think going SMT
                    > > again is going to make life any easier):
                    > > http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf
                    > >
                    > > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                    > >>
                    > >> Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at 10k
                    > >> as it should, but with it pulled there is very little voltage at pin 2.
                    > >> The current, since I can now measure it, across R16 is .24mA. The votage
                    > >> at pin 7 doesn't change either; it's still almost zero. The others
                    > >> besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had
                    > >> been reading. I guess R16 becomes part of a voltage divider under the
                    > >> circumstances; I don't understand circuits this complex. So I will try to
                    > >> unseat U6 and see if there is a solder bridge under it from 1 to 8 or
                    > >> something (they are across from each other).
                    >
                  • wfahle
                    See the epitaph elsewhere in this thread. I was using a 50W velleman temperature controlled soldering station, with a 3mm tip, which seems to have worked in
                    Message 9 of 28 , Nov 1, 2012
                    • 0 Attachment
                      See the epitaph elsewhere in this thread. I was using a 50W velleman temperature controlled soldering station, with a 3mm tip, which seems to have worked in most cases except for the removal. If you look at the pictures I think you will agree it was a fine soldering job; I never spent more than a second or two with the iron to the board, except maybe when soldering ground leads for resistors and such. That copper can suck up the heat.

                      I suspect a static hit, as I was taking few precautions and another chip bit the dust somewhere in there too (not to mention a temperature drop requiring the heater to be run).

                      --- In softrock40@yahoogroups.com, Lawrence Galea <galea_lawrence@...> wrote:
                      >
                      > ps.
                      > by the way, some problems are caused by not having high enough heat and having to keep the soldering iron too long on the pcb or a soldering iron which is not big enough to heat a big soldering pad especially when a chip or other component is already soldered or when a chip has a tab which has to be soldered to the pcb. When soldering a tab to the pcb, a 100W soldering gun will make the job much quicker and easier with less chance of damage to the pcb and the component than a soldering iron with a very fine tip as the time needed with the gun will be just a second or two while it will take much longer with a small fine-tipped iron. This is apart form the soldering being much easier and neater
                      > Hope this helps.
                      > Regards
                      > Lawrence
                      >
                      >
                      >
                      >
                      >
                      > ________________________________
                      > Da: Lawrence Galea <galea_lawrence@...>
                      > A: "softrock40@yahoogroups.com" <softrock40@yahoogroups.com>
                      > Inviato: Giovedì 1 Novembre 2012 8:34
                      > Oggetto: Re: [softrock40] Re: Bad chip?
                      >
                      >
                      >  
                      > Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a suitable solder pad near one side of the chip, then heat the pins one by one starting from the one farthest away from where you soldered the wire to the solder pad and when the solder melts pull the wire under the pin. This will push up the pin from the pcb. Do all the pins on one side and them to the other side.
                      > Regards
                      > Lawrence
                      >
                      >                               Chip pins
                      >
                      >                                      ----------------
                      >  Solder pad  0-------------------------------------------------------Wire
                      >
                      >                                      |                      |
                      >                                          Chip
                      >
                      >                                      ----------------
                      >
                      >
                      > Hope this explains.
                      >
                      > 0 is solder pad where wire is soldered
                      > First heat the pin from the right hand side on the diagram and when solder melts pull the wire under the pin to the top of the page in this diagram and move towards the left pin by pin.
                      >
                      > Then do the same to the other side.
                      >
                      > ________________________________
                      > Da: warrenallgyer <allgyer@...>
                      > A: softrock40@yahoogroups.com
                      > Inviato: Giovedì 1 Novembre 2012 0:16
                      > Oggetto: [softrock40] Re: Bad chip?
                      >
                      >
                      >  
                      > Bill
                      >
                      > I feel your pain.... been there, done that... more than once in fact.
                      >
                      > A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.
                      >
                      > After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.
                      >
                      > Good luck to you.
                      >
                      > Warren Allgyer - W8TOD
                      >
                      > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                      > >
                      > > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):
                      >
                    • Sid Boyce
                      You can consider yourself lucky if a zap killed the device rather than weakening it and causing intermittent problems may be some time way after it has been
                      Message 10 of 28 , Nov 1, 2012
                      • 0 Attachment
                        You can consider yourself lucky if a zap killed the device rather than weakening it and causing intermittent problems may be some time way after it has been working perfectly.

                        ESD precautions are always advised.
                        73 ... Sid.

                        On 01/11/12 13:00, wfahle wrote:
                         

                        See the epitaph elsewhere in this thread. I was using a 50W velleman temperature controlled soldering station, with a 3mm tip, which seems to have worked in most cases except for the removal. If you look at the pictures I think you will agree it was a fine soldering job; I never spent more than a second or two with the iron to the board, except maybe when soldering ground leads for resistors and such. That copper can suck up the heat.

                        I suspect a static hit, as I was taking few precautions and another chip bit the dust somewhere in there too (not to mention a temperature drop requiring the heater to be run).

                        --- In softrock40@yahoogroups.com, Lawrence Galea <galea_lawrence@...> wrote:
                        >
                        > ps.
                        > by the way, some problems are caused by not having high enough heat and having to keep the soldering iron too long on the pcb or a soldering iron which is not big enough to heat a big soldering pad especially when a chip or other component is already soldered or when a chip has a tab which has to be soldered to the pcb. When soldering a tab to the pcb, a 100W soldering gun will make the job much quicker and easier with less chance of damage to the pcb and the component than a soldering iron with a very fine tip as the time needed with the gun will be just a second or two while it will take much longer with a small fine-tipped iron. This is apart form the soldering being much easier and neater
                        > Hope this helps.
                        > Regards
                        > Lawrence
                        >
                        >
                        >
                        >
                        >
                        > ________________________________
                        > Da: Lawrence Galea <galea_lawrence@...>
                        > A: "softrock40@yahoogroups.com" <softrock40@yahoogroups.com>
                        > Inviato: Giovedì 1 Novembre 2012 8:34
                        > Oggetto: Re: [softrock40] Re: Bad chip?
                        >
                        >
                        >  
                        > Another trick is to tread a thin insulated wire or a wire which does not take solder easily under the pins on one side, solder the end of the wire to a suitable solder pad near one side of the chip, then heat the pins one by one starting from the one farthest away from where you soldered the wire to the solder pad and when the solder melts pull the wire under the pin. This will push up the pin from the pcb. Do all the pins on one side and them to the other side.
                        > Regards
                        > Lawrence
                        >
                        >                               Chip pins
                        >
                        >                                      ----------------
                        >  Solder pad  0-------------------------------------------------------Wire
                        >
                        >                                      |                      |
                        >                                          Chip
                        >
                        >                                      ----------------
                        >
                        >
                        > Hope this explains.
                        >
                        > 0 is solder pad where wire is soldered
                        > First heat the pin from the right hand side on the diagram and when solder melts pull the wire under the pin to the top of the page in this diagram and move towards the left pin by pin.
                        >
                        > Then do the same to the other side.
                        >
                        > ________________________________
                        > Da: warrenallgyer <allgyer@...>
                        > A: softrock40@yahoogroups.com
                        > Inviato: Giovedì 1 Novembre 2012 0:16
                        > Oggetto: [softrock40] Re: Bad chip?
                        >
                        >
                        >  
                        > Bill
                        >
                        > I feel your pain.... been there, done that... more than once in fact.
                        >
                        > A trick that will not help you now but may in the future: When removing multi-pin SMT devices I first solder all the pins together, using as little solder as possible. Then, when you apply the iron it can loosen one complete side at the same time. Carefully bending the chip up with needle nose applied to the ends will free this side. Then do the same on the other side and the chip comes up with minimal damage. Solderwick will clean up the lands and you are ready to install a replacement.
                        >
                        > After many many lands lifted and chips destroyed (I am a slow-learner) this trick has saved the day many times.
                        >
                        > Good luck to you.
                        >
                        > Warren Allgyer - W8TOD
                        >
                        > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                        > >
                        > > Well NOW it's the chip for sure. In an attempt to remove the IC to check voltages and such, the green covering began to burn through exposing the copper traces beneath. So I got out the clippers and clipped it loose from the board, so that I could remove each lead individually. This worked, but it tore up some of the pads in the process. I intend to replace it with this chip because it is available locally (and I don't think going SMT again is going to make life any easier):
                        >



                        -- 
                        Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                        Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                        Senior Staff Specialist, Cricket Coach
                        Microsoft Windows Free Zone - Linux used for all Computing Tasks
                        
                      • wfahle
                        It s embarrassing to admit this but here goes: Problem: unit doesn t kerchunk when connecting to USB Solution: pick up the earphones off the desk. ... Mind
                        Message 11 of 28 , Nov 1, 2012
                        • 0 Attachment
                          It's embarrassing to admit this but here goes:
                          Problem: unit doesn't kerchunk when connecting to USB
                          Solution: pick up the earphones off the desk.
                          :/

                          Mind you, the voltage was still bad on that one chip. So I do have work to do if I want a transmitter. Received a good signal again tonight.

                          --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@...> wrote:
                          >
                          > You can consider yourself lucky if a zap killed the device rather than
                          > weakening it and causing intermittent problems may be some time way
                          > after it has been working perfectly.
                          >
                          > ESD precautions are always advised.
                          > 73 ... Sid.
                          >
                          > On 01/11/12 13:00, wfahle wrote:
                          > >
                          > > See the epitaph elsewhere in this thread. I was using a 50W velleman
                          > > temperature controlled soldering station, with a 3mm tip, which seems
                          > > to have worked in most cases except for the removal. If you look at
                          > > the pictures I think you will agree it was a fine soldering job; I
                          > > never spent more than a second or two with the iron to the board,
                          > > except maybe when soldering ground leads for resistors and such. That
                          > > copper can suck up the heat.
                          > >
                          > > I suspect a static hit, as I was taking few precautions and another
                          > > chip bit the dust somewhere in there too (not to mention a temperature
                          > > drop requiring the heater to be run).
                          > >
                          > > --- In softrock40@yahoogroups.com
                          > > <mailto:softrock40%40yahoogroups.com>, Lawrence Galea
                          > > <galea_lawrence@> wrote:
                          > > >
                          > > > ps.
                          > > > by the way, some problems are caused by not having high enough heat
                          > > and having to keep the soldering iron too long on the pcb or a
                          > > soldering iron which is not big enough to heat a big soldering pad
                          > > especially when a chip or other component is already soldered or when
                          > > a chip has a tab which has to be soldered to the pcb. When soldering a
                          > > tab to the pcb, a 100W soldering gun will make the job much quicker
                          > > and easier with less chance of damage to the pcb and the component
                          > > than a soldering iron with a very fine tip as the time needed with the
                          > > gun will be just a second or two while it will take much longer with a
                          > > small fine-tipped iron. This is apart form the soldering being much
                          > > easier and neater
                          > > > Hope this helps.
                          > > > Regards
                          > > > Lawrence
                          > > >
                          > > >
                          > > >
                          > > >
                          > > >
                          > > > ________________________________
                          > > > Da: Lawrence Galea <galea_lawrence@>
                          > > > A: "softrock40@yahoogroups.com
                          > > <mailto:softrock40%40yahoogroups.com>" <softrock40@yahoogroups.com
                          > > <mailto:softrock40%40yahoogroups.com>>
                          > > > Inviato: Giovedì 1 Novembre 2012 8:34
                          > > > Oggetto: Re: [softrock40] Re: Bad chip?
                          > > >
                          > > >
                          > > > Â
                          > > > Another trick is to tread a thin insulated wire or a wire which does
                          > > not take solder easily under the pins on one side, solder the end of
                          > > the wire to a suitable solder pad near one side of the chip, then heat
                          > > the pins one by one starting from the one farthest away from where you
                          > > soldered the wire to the solder pad and when the solder melts pull the
                          > > wire under the pin. This will push up the pin from the pcb. Do all the
                          > > pins on one side and them to the other side.
                          > > > Regards
                          > > > Lawrence
                          > > >
                          > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Chip pins
                          > > >
                          > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                          > > ----------------
                          > > > Â Solder padÂ
                          > > 0-------------------------------------------------------Wire
                          > > >
                          > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                          > > |Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â |
                          > > >
                          > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                          > > Chip
                          > > >
                          > > >
                          > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ----------------
                          > > >
                          > > >
                          > > > Hope this explains.
                          > > >
                          > > > 0 is solder pad where wire is soldered
                          > > > First heat the pin from the right hand side on the diagram and when
                          > > solder melts pull the wire under the pin to the top of the page in
                          > > this diagram and move towards the left pin by pin.
                          > > >
                          > > > Then do the same to the other side.
                          > > >
                          > > > ________________________________
                          > > > Da: warrenallgyer <allgyer@>
                          > > > A: softrock40@yahoogroups.com <mailto:softrock40%40yahoogroups.com>
                          > > > Inviato: Giovedì 1 Novembre 2012 0:16
                          > > > Oggetto: [softrock40] Re: Bad chip?
                          > > >
                          > > >
                          > > > Â
                          > > > Bill
                          > > >
                          > > > I feel your pain.... been there, done that... more than once in fact.
                          > > >
                          > > > A trick that will not help you now but may in the future: When
                          > > removing multi-pin SMT devices I first solder all the pins together,
                          > > using as little solder as possible. Then, when you apply the iron it
                          > > can loosen one complete side at the same time. Carefully bending the
                          > > chip up with needle nose applied to the ends will free this side. Then
                          > > do the same on the other side and the chip comes up with minimal
                          > > damage. Solderwick will clean up the lands and you are ready to
                          > > install a replacement.
                          > > >
                          > > > After many many lands lifted and chips destroyed (I am a
                          > > slow-learner) this trick has saved the day many times.
                          > > >
                          > > > Good luck to you.
                          > > >
                          > > > Warren Allgyer - W8TOD
                          > > >
                          > > > --- In softrock40@yahoogroups.com
                          > > <mailto:softrock40%40yahoogroups.com>, "wfahle" <billfahle@> wrote:
                          > > > >
                          > > > > Well NOW it's the chip for sure. In an attempt to remove the IC to
                          > > check voltages and such, the green covering began to burn through
                          > > exposing the copper traces beneath. So I got out the clippers and
                          > > clipped it loose from the board, so that I could remove each lead
                          > > individually. This worked, but it tore up some of the pads in the
                          > > process. I intend to replace it with this chip because it is available
                          > > locally (and I don't think going SMT again is going to make life any
                          > > easier):
                          > > >
                          > >
                          > >
                          >
                          >
                          > --
                          > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                          > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                          > Senior Staff Specialist, Cricket Coach
                          > Microsoft Windows Free Zone - Linux used for all Computing Tasks
                          >
                        • Sid Boyce
                          Things happen now, in the past and will in the future. We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app
                          Message 12 of 28 , Nov 2, 2012
                          • 0 Attachment
                            Things happen now, in the past and will in the future.
                            We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app has lost sound - been there, done that.
                            73 ... Sid.

                            On 02/11/12 02:32, wfahle wrote:
                             

                            It's embarrassing to admit this but here goes:
                            Problem: unit doesn't kerchunk when connecting to USB
                            Solution: pick up the earphones off the desk.
                            :/

                            Mind you, the voltage was still bad on that one chip. So I do have work to do if I want a transmitter. Received a good signal again tonight.

                            --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@...> wrote:
                            >
                            > You can consider yourself lucky if a zap killed the device rather than
                            > weakening it and causing intermittent problems may be some time way
                            > after it has been working perfectly.
                            >
                            > ESD precautions are always advised.
                            > 73 ... Sid.
                            >
                            > On 01/11/12 13:00, wfahle wrote:
                            > >
                            > > See the epitaph elsewhere in this thread. I was using a 50W velleman
                            > > temperature controlled soldering station, with a 3mm tip, which seems
                            > > to have worked in most cases except for the removal. If you look at
                            > > the pictures I think you will agree it was a fine soldering job; I
                            > > never spent more than a second or two with the iron to the board,
                            > > except maybe when soldering ground leads for resistors and such. That
                            > > copper can suck up the heat.
                            > >
                            > > I suspect a static hit, as I was taking few precautions and another
                            > > chip bit the dust somewhere in there too (not to mention a temperature
                            > > drop requiring the heater to be run).
                            > >
                            > > --- In softrock40@yahoogroups.com
                            > > <mailto:softrock40%40yahoogroups.com>, Lawrence Galea
                            > > <galea_lawrence@> wrote:
                            > > >
                            > > > ps.
                            > > > by the way, some problems are caused by not having high enough heat
                            > > and having to keep the soldering iron too long on the pcb or a
                            > > soldering iron which is not big enough to heat a big soldering pad
                            > > especially when a chip or other component is already soldered or when
                            > > a chip has a tab which has to be soldered to the pcb. When soldering a
                            > > tab to the pcb, a 100W soldering gun will make the job much quicker
                            > > and easier with less chance of damage to the pcb and the component
                            > > than a soldering iron with a very fine tip as the time needed with the
                            > > gun will be just a second or two while it will take much longer with a
                            > > small fine-tipped iron. This is apart form the soldering being much
                            > > easier and neater
                            > > > Hope this helps.
                            > > > Regards
                            > > > Lawrence
                            > > >
                            > > >
                            > > >
                            > > >
                            > > >
                            > > > ________________________________
                            > > > Da: Lawrence Galea <galea_lawrence@>
                            > > > A: "softrock40@yahoogroups.com
                            > > <mailto:softrock40%40yahoogroups.com>" <softrock40@yahoogroups.com
                            > > <mailto:softrock40%40yahoogroups.com>>
                            > > > Inviato: Giovedì 1 Novembre 2012 8:34
                            > > > Oggetto: Re: [softrock40] Re: Bad chip?
                            > > >
                            > > >
                            > > > Â
                            > > > Another trick is to tread a thin insulated wire or a wire which does
                            > > not take solder easily under the pins on one side, solder the end of
                            > > the wire to a suitable solder pad near one side of the chip, then heat
                            > > the pins one by one starting from the one farthest away from where you
                            > > soldered the wire to the solder pad and when the solder melts pull the
                            > > wire under the pin. This will push up the pin from the pcb. Do all the
                            > > pins on one side and them to the other side.
                            > > > Regards
                            > > > Lawrence
                            > > >
                            > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Chip pins
                            > > >
                            > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                            > > ----------------
                            > > > Â Solder padÂ
                            > > 0-------------------------------------------------------Wire
                            > > >
                            > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                            > > |Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â |
                            > > >
                            > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                            > > Chip
                            > > >
                            > > >
                            > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ----------------
                            > > >
                            > > >
                            > > > Hope this explains.
                            > > >
                            > > > 0 is solder pad where wire is soldered
                            > > > First heat the pin from the right hand side on the diagram and when
                            > > solder melts pull the wire under the pin to the top of the page in
                            > > this diagram and move towards the left pin by pin.
                            > > >
                            > > > Then do the same to the other side.
                            > > >
                            > > > ________________________________
                            > > > Da: warrenallgyer <allgyer@>
                            > > > A: softrock40@yahoogroups.com <mailto:softrock40%40yahoogroups.com>
                            > > > Inviato: Giovedì 1 Novembre 2012 0:16
                            > > > Oggetto: [softrock40] Re: Bad chip?
                            > > >
                            > > >
                            > > > Â
                            > > > Bill
                            > > >
                            > > > I feel your pain.... been there, done that... more than once in fact.
                            > > >
                            > > > A trick that will not help you now but may in the future: When
                            > > removing multi-pin SMT devices I first solder all the pins together,
                            > > using as little solder as possible. Then, when you apply the iron it
                            > > can loosen one complete side at the same time. Carefully bending the
                            > > chip up with needle nose applied to the ends will free this side. Then
                            > > do the same on the other side and the chip comes up with minimal
                            > > damage. Solderwick will clean up the lands and you are ready to
                            > > install a replacement.
                            > > >
                            > > > After many many lands lifted and chips destroyed (I am a
                            > > slow-learner) this trick has saved the day many times.
                            > > >
                            > > > Good luck to you.
                            > > >
                            > > > Warren Allgyer - W8TOD
                            > > >
                            > > > --- In softrock40@yahoogroups.com
                            > > <mailto:softrock40%40yahoogroups.com>, "wfahle" <billfahle@> wrote:
                            > > > >
                            > > > > Well NOW it's the chip for sure. In an attempt to remove the IC to
                            > > check voltages and such, the green covering began to burn through
                            > > exposing the copper traces beneath. So I got out the clippers and
                            > > clipped it loose from the board, so that I could remove each lead
                            > > individually. This worked, but it tore up some of the pads in the
                            > > process. I intend to replace it with this chip because it is available
                            > > locally (and I don't think going SMT again is going to make life any
                            > > easier):
                            > > >
                            > >
                            > >
                            >
                            >
                            > --
                            > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                            > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                            > Senior Staff Specialist, Cricket Coach
                            > Microsoft Windows Free Zone - Linux used for all Computing Tasks
                            >



                            -- 
                            Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                            Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                            Senior Staff Specialist, Cricket Coach
                            Microsoft Windows Free Zone - Linux used for all Computing Tasks
                            
                          • John Rabson
                            ... When I was running the e-mail system for a major organisation, I received an annoyed phone call from the Director one Monday morning, complaining that his
                            Message 13 of 28 , Nov 2, 2012
                            • 0 Attachment
                              On 2 Nov 2012, at 12:39CET, Sid Boyce wrote:

                               

                              Things happen now, in the past and will in the future.
                              We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app has lost sound - been there, done that.
                              73 ... Sid.

                              When I was running the e-mail system for a major organisation, I received an annoyed phone call from the Director one Monday morning, complaining that his e-mail system did not work.

                              I sent my most diplomatic technician to find out what had happened. He reported back a few minutes later -  the client had forgotten to switch his monitor on (in those days monitors tended to have separate power feeds and were always switched off at the weekend).

                              John F5VLF


                            • wfahle
                              Well I m a mere Ph.D. in computer science with 20 years in the industry, so yes, I ve done this sort of thing dozens of times! PEBKAC
                              Message 14 of 28 , Nov 2, 2012
                              • 0 Attachment
                                Well I'm a mere Ph.D. in computer science with 20 years in the industry, so yes, I've done this sort of thing dozens of times! PEBKAC

                                --- In softrock40@yahoogroups.com, John Rabson <john.rabson@...> wrote:
                                >
                                > On 2 Nov 2012, at 12:39CET, Sid Boyce wrote:
                                >
                                > >
                                > > Things happen now, in the past and will in the future.
                                > > We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app has lost sound - been there, done that.
                                > > 73 ... Sid.
                                >
                                > When I was running the e-mail system for a major organisation, I received an annoyed phone call from the Director one Monday morning, complaining that his e-mail system did not work.
                                >
                                > I sent my most diplomatic technician to find out what had happened. He reported back a few minutes later - the client had forgotten to switch his monitor on (in those days monitors tended to have separate power feeds and were always switched off at the weekend).
                                >
                                > John F5VLF
                                > >
                                >
                              • Anthony Casorso
                                PHd? Well, that explains it! ;) TonyBS EE (But master of BS)To: softrock40@yahoogroups.com From: billfahle@gmail.com Date: Fri, 2 Nov 2012 13:23:45 +0000
                                Message 15 of 28 , Nov 2, 2012
                                • 0 Attachment

                                   PHd?  Well, that explains it!   ;)
                                   
                                  Tony
                                  BS EE (But master of BS)

                                  To: softrock40@yahoogroups.com
                                  From: billfahle@...
                                  Date: Fri, 2 Nov 2012 13:23:45 +0000
                                  Subject: [softrock40] Re: Bad chip?

                                   
                                  Well I'm a mere Ph.D. in computer science with 20 years in the industry, so yes, I've done this sort of thing dozens of times! PEBKAC

                                  --- In softrock40@yahoogroups.com, John Rabson <john.rabson@...> wrote:
                                  >
                                  > On 2 Nov 2012, at 12:39CET, Sid Boyce wrote:
                                  >
                                  > >
                                  > > Things happen now, in the past and will in the future.
                                  > > We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app has lost sound - been there, done that.
                                  > > 73 ... Sid.
                                  >
                                  > When I was running the e-mail system for a major organisation, I received an annoyed phone call from the Director one Monday morning, complaining that his e-mail system did not work.
                                  >
                                  > I sent my most diplomatic technician to find out what had happened. He reported back a few minutes later - the client had forgotten to switch his monitor on (in those days monitors tended to have separate power feeds and were always switched off at the weekend).
                                  >
                                  > John F5VLF
                                  > >
                                  >


                                • John Greusel
                                  I just had one recently- I was certain I had blown the BS170s with an inadvertent key down for 10 minutes and replaced them. Turned out it was a short in the
                                  Message 16 of 28 , Nov 2, 2012
                                  • 0 Attachment
                                    I just had one recently- I was certain I had blown the BS170s with an inadvertent key down for 10 minutes and replaced them.
                                    Turned out it was a short in the microphone. The noise was horrendous.

                                    John
                                    KC9OJV

                                     



                                    From: Sid Boyce <sboyce@...>
                                    To: softrock40@yahoogroups.com
                                    Sent: Friday, November 2, 2012 6:39 AM
                                    Subject: Re: [softrock40] Re: Bad chip?

                                     
                                    Things happen now, in the past and will in the future.
                                    We all go there - turn the speaker volume down to take a phone call and much later wonder if the SDR app has lost sound - been there, done that.
                                    73 ... Sid.

                                    On 02/11/12 02:32, wfahle wrote:
                                     
                                    It's embarrassing to admit this but here goes:
                                    Problem: unit doesn't kerchunk when connecting to USB
                                    Solution: pick up the earphones off the desk.
                                    :/

                                    Mind you, the voltage was still bad on that one chip. So I do have work to do if I want a transmitter. Received a good signal again tonight.

                                    --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@...> wrote:
                                    >
                                    > You can consider yourself lucky if a zap killed the device rather than
                                    > weakening it and causing intermittent problems may be some time way
                                    > after it has been working perfectly.
                                    >
                                    > ESD precautions are always advised.
                                    > 73 ... Sid.
                                    >
                                    > On 01/11/12 13:00, wfahle wrote:
                                    > >
                                    > > See the epitaph elsewhere in this thread. I was using a 50W velleman
                                    > > temperature controlled soldering station, with a 3mm tip, which seems
                                    > > to have worked in most cases except for the removal. If you look at
                                    > > the pictures I think you will agree it was a fine soldering job; I
                                    > > never spent more than a second or two with the iron to the board,
                                    > > except maybe when soldering ground leads for resistors and such. That
                                    > > copper can suck up the heat.
                                    > >
                                    > > I suspect a static hit, as I was taking few precautions and another
                                    > > chip bit the dust somewhere in there too (not to mention a temperature
                                    > > drop requiring the heater to be run).
                                    > >
                                    > > --- In softrock40@yahoogroups.com
                                    > > <mailto:softrock40%40yahoogroups.com>, Lawrence Galea
                                    > > <galea_lawrence@> wrote:
                                    > > >
                                    > > > ps.
                                    > > > by the way, some problems are caused by not having high enough heat
                                    > > and having to keep the soldering iron too long on the pcb or a
                                    > > soldering iron which is not big enough to heat a big soldering pad
                                    > > especially when a chip or other component is already soldered or when
                                    > > a chip has a tab which has to be soldered to the pcb. When soldering a
                                    > > tab to the pcb, a 100W soldering gun will make the job much quicker
                                    > > and easier with less chance of damage to the pcb and the component
                                    > > than a soldering iron with a very fine tip as the time needed with the
                                    > > gun will be just a second or two while it will take much longer with a
                                    > > small fine-tipped iron. This is apart form the soldering being much
                                    > > easier and neater
                                    > > > Hope this helps.
                                    > > > Regards
                                    > > > Lawrence
                                    > > >
                                    > > >
                                    > > >
                                    > > >
                                    > > >
                                    > > > ________________________________
                                    > > > Da: Lawrence Galea <galea_lawrence@>
                                    > > > A: "softrock40@yahoogroups.com
                                    > > <mailto:softrock40%40yahoogroups.com>" <softrock40@yahoogroups.com
                                    > > <mailto:softrock40%40yahoogroups.com>>
                                    > > > Inviato: Giovedì 1 Novembre 2012 8:34
                                    > > > Oggetto: Re: [softrock40] Re: Bad chip?
                                    > > >
                                    > > >
                                    > > > Â
                                    > > > Another trick is to tread a thin insulated wire or a wire which does
                                    > > not take solder easily under the pins on one side, solder the end of
                                    > > the wire to a suitable solder pad near one side of the chip, then heat
                                    > > the pins one by one starting from the one farthest away from where you
                                    > > soldered the wire to the solder pad and when the solder melts pull the
                                    > > wire under the pin. This will push up the pin from the pcb. Do all the
                                    > > pins on one side and them to the other side.
                                    > > > Regards
                                    > > > Lawrence
                                    > > >
                                    > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Chip pins
                                    > > >
                                    > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                                    > > ----------------
                                    > > > Â Solder padÂ
                                    > > 0-------------------------------------------------------Wire
                                    > > >
                                    > > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                                    > > |Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â |
                                    > > >
                                    > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
                                    > > Chip
                                    > > >
                                    > > >
                                    > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ----------------
                                    > > >
                                    > > >
                                    > > > Hope this explains.
                                    > > >
                                    > > > 0 is solder pad where wire is soldered
                                    > > > First heat the pin from the right hand side on the diagram and when
                                    > > solder melts pull the wire under the pin to the top of the page in
                                    > > this diagram and move towards the left pin by pin.
                                    > > >
                                    > > > Then do the same to the other side.
                                    > > >
                                    > > > ________________________________
                                    > > > Da: warrenallgyer <allgyer@>
                                    > > > A: softrock40@yahoogroups.com <mailto:softrock40%40yahoogroups.com>
                                    > > > Inviato: Giovedì 1 Novembre 2012 0:16
                                    > > > Oggetto: [softrock40] Re: Bad chip?
                                    > > >
                                    > > >
                                    > > > Â
                                    > > > Bill
                                    > > >
                                    > > > I feel your pain.... been there, done that... more than once in fact.
                                    > > >
                                    > > > A trick that will not help you now but may in the future: When
                                    > > removing multi-pin SMT devices I first solder all the pins together,
                                    > > using as little solder as possible. Then, when you apply the iron it
                                    > > can loosen one complete side at the same time. Carefully bending the
                                    > > chip up with needle nose applied to the ends will free this side. Then
                                    > > do the same on the other side and the chip comes up with minimal
                                    > > damage. Solderwick will clean up the lands and you are ready to
                                    > > install a replacement.
                                    > > >
                                    > > > After many many lands lifted and chips destroyed (I am a
                                    > > slow-learner) this trick has saved the day many times.
                                    > > >
                                    > > > Good luck to you.
                                    > > >
                                    > > > Warren Allgyer - W8TOD
                                    > > >
                                    > > > --- In softrock40@yahoogroups.com
                                    > > <mailto:softrock40%40yahoogroups.com>, "wfahle" <billfahle@> wrote:
                                    > > > >
                                    > > > > Well NOW it's the chip for sure. In an attempt to remove the IC to
                                    > > check voltages and such, the green covering began to burn through
                                    > > exposing the copper traces beneath. So I got out the clippers and
                                    > > clipped it loose from the board, so that I could remove each lead
                                    > > individually. This worked, but it tore up some of the pads in the
                                    > > process. I intend to replace it with this chip because it is available
                                    > > locally (and I don't think going SMT again is going to make life any
                                    > > easier):
                                    > > >
                                    > >
                                    > >
                                    >
                                    >
                                    > --
                                    > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                                    > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                                    > Senior Staff Specialist, Cricket Coach
                                    > Microsoft Windows Free Zone - Linux used for all Computing Tasks
                                    >



                                    -- 
                                    Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                                    Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                                    Senior Staff Specialist, Cricket Coach
                                    Microsoft Windows Free Zone - Linux used for all Computing Tasks
                                    


                                  • wfahle
                                    Ok, I ve recovered from the brain fart, and am back on track now. This OP-Amp (dual) is in the transmitter, as U6. Do you think noise will cause a problem? I
                                    Message 17 of 28 , Nov 2, 2012
                                    • 0 Attachment
                                      Ok, I've recovered from the brain fart, and am back on track now. This OP-Amp (dual) is in the transmitter, as U6. Do you think noise will cause a problem? I think I will try it anyway this weekend, because I am installing it dead-bug style with individual wires to each lead, so it will be easily replaced. This will allow me to finish the transmitter and see what I get signal-report wise.

                                      --- In softrock40@yahoogroups.com, "MICHAEL TALLENT" <mwtallent@...> wrote:
                                      >
                                      > You really want a low noise op-amp for this application as it will determine
                                      > the noise floor of your receiver. The data sheet you linked looks like
                                      > nothing special, so you will not get the performance that these receivers
                                      > are capable of.
                                      >
                                      > Mike T W6MXV
                                      >
                                      > ----- Original Message -----
                                      > From: "wfahle" <billfahle@...>
                                      > To: <softrock40@yahoogroups.com>
                                      > Sent: Wednesday, October 31, 2012 12:31 PM
                                      > Subject: [softrock40] Re: Bad chip?
                                      >
                                      >
                                      > > Well NOW it's the chip for sure. In an attempt to remove the IC to check
                                      > > voltages and such, the green covering began to burn through exposing the
                                      > > copper traces beneath. So I got out the clippers and clipped it loose from
                                      > > the board, so that I could remove each lead individually. This worked, but
                                      > > it tore up some of the pads in the process. I intend to replace it with
                                      > > this chip because it is available locally (and I don't think going SMT
                                      > > again is going to make life any easier):
                                      > > http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf
                                      > >
                                      > > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                                      > >>
                                      > >> Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at 10k
                                      > >> as it should, but with it pulled there is very little voltage at pin 2.
                                      > >> The current, since I can now measure it, across R16 is .24mA. The votage
                                      > >> at pin 7 doesn't change either; it's still almost zero. The others
                                      > >> besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had
                                      > >> been reading. I guess R16 becomes part of a voltage divider under the
                                      > >> circumstances; I don't understand circuits this complex. So I will try to
                                      > >> unseat U6 and see if there is a solder bridge under it from 1 to 8 or
                                      > >> something (they are across from each other).
                                      >
                                    • MICHAEL TALLENT
                                      Noise probably will not matter for the transmitting side, the output level may not be as good as amps designed for low voltage operation, but try it and see.
                                      Message 18 of 28 , Nov 2, 2012
                                      • 0 Attachment
                                        Noise probably will not matter for the transmitting side, the output level
                                        may not be as good as amps designed for low voltage operation, but try it
                                        and see.

                                        Mike T

                                        ----- Original Message -----
                                        From: "wfahle" <billfahle@...>
                                        To: <softrock40@yahoogroups.com>
                                        Sent: Friday, November 02, 2012 12:46 PM
                                        Subject: [softrock40] Re: Bad chip?


                                        > Ok, I've recovered from the brain fart, and am back on track now. This
                                        > OP-Amp (dual) is in the transmitter, as U6. Do you think noise will cause
                                        > a problem? I think I will try it anyway this weekend, because I am
                                        > installing it dead-bug style with individual wires to each lead, so it
                                        > will be easily replaced. This will allow me to finish the transmitter and
                                        > see what I get signal-report wise.
                                        >
                                        > --- In softrock40@yahoogroups.com, "MICHAEL TALLENT" <mwtallent@...>
                                        > wrote:
                                        >>
                                        >> You really want a low noise op-amp for this application as it will
                                        >> determine
                                        >> the noise floor of your receiver. The data sheet you linked looks like
                                        >> nothing special, so you will not get the performance that these receivers
                                        >> are capable of.
                                        >>
                                        >> Mike T W6MXV
                                        >>
                                        >> ----- Original Message -----
                                        >> From: "wfahle" <billfahle@...>
                                        >> To: <softrock40@yahoogroups.com>
                                        >> Sent: Wednesday, October 31, 2012 12:31 PM
                                        >> Subject: [softrock40] Re: Bad chip?
                                        >>
                                        >>
                                        >> > Well NOW it's the chip for sure. In an attempt to remove the IC to
                                        >> > check
                                        >> > voltages and such, the green covering began to burn through exposing
                                        >> > the
                                        >> > copper traces beneath. So I got out the clippers and clipped it loose
                                        >> > from
                                        >> > the board, so that I could remove each lead individually. This worked,
                                        >> > but
                                        >> > it tore up some of the pads in the process. I intend to replace it with
                                        >> > this chip because it is available locally (and I don't think going SMT
                                        >> > again is going to make life any easier):
                                        >> > http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf
                                        >> >
                                        >> > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                                        >> >>
                                        >> >> Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at
                                        >> >> 10k
                                        >> >> as it should, but with it pulled there is very little voltage at pin
                                        >> >> 2.
                                        >> >> The current, since I can now measure it, across R16 is .24mA. The
                                        >> >> votage
                                        >> >> at pin 7 doesn't change either; it's still almost zero. The others
                                        >> >> besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had
                                        >> >> been reading. I guess R16 becomes part of a voltage divider under the
                                        >> >> circumstances; I don't understand circuits this complex. So I will try
                                        >> >> to
                                        >> >> unseat U6 and see if there is a solder bridge under it from 1 to 8 or
                                        >> >> something (they are across from each other).
                                        >>
                                      • wfahle
                                        It indicates 5v on pin 1, Just like the other one in that respect. With power off, I m currently reading 20.9 Kohms between pin 1 and pin 8, which when
                                        Message 19 of 28 , Nov 3, 2012
                                        • 0 Attachment
                                          It indicates 5v on pin 1, Just like the other one in that respect. With power off, I'm currently reading 20.9 Kohms between pin 1 and pin 8, which when reviewing the schematic doesn't seem right. In fact the other dual op-amp which seems wired similarly is an open circuit between those pins, giving me more confidence that this is the problem. I'm reading 11Kohms between 8 and 2 on U6, which is probably where the 20.9 is coming from adding R16 (which spans 1 and 2). Any ideas anyone? Clearly there is a short somewhere, and not a bad chip after all.

                                          --- In softrock40@yahoogroups.com, "MICHAEL TALLENT" <mwtallent@...> wrote:
                                          >
                                          > Noise probably will not matter for the transmitting side, the output level
                                          > may not be as good as amps designed for low voltage operation, but try it
                                          > and see.
                                          >
                                          > Mike T
                                          >
                                          > ----- Original Message -----
                                          > From: "wfahle" <billfahle@...>
                                          > To: <softrock40@yahoogroups.com>
                                          > Sent: Friday, November 02, 2012 12:46 PM
                                          > Subject: [softrock40] Re: Bad chip?
                                          >
                                          >
                                          > > Ok, I've recovered from the brain fart, and am back on track now. This
                                          > > OP-Amp (dual) is in the transmitter, as U6. Do you think noise will cause
                                          > > a problem? I think I will try it anyway this weekend, because I am
                                          > > installing it dead-bug style with individual wires to each lead, so it
                                          > > will be easily replaced. This will allow me to finish the transmitter and
                                          > > see what I get signal-report wise.
                                          > >
                                          > > --- In softrock40@yahoogroups.com, "MICHAEL TALLENT" <mwtallent@>
                                          > > wrote:
                                          > >>
                                          > >> You really want a low noise op-amp for this application as it will
                                          > >> determine
                                          > >> the noise floor of your receiver. The data sheet you linked looks like
                                          > >> nothing special, so you will not get the performance that these receivers
                                          > >> are capable of.
                                          > >>
                                          > >> Mike T W6MXV
                                          > >>
                                          > >> ----- Original Message -----
                                          > >> From: "wfahle" <billfahle@>
                                          > >> To: <softrock40@yahoogroups.com>
                                          > >> Sent: Wednesday, October 31, 2012 12:31 PM
                                          > >> Subject: [softrock40] Re: Bad chip?
                                          > >>
                                          > >>
                                          > >> > Well NOW it's the chip for sure. In an attempt to remove the IC to
                                          > >> > check
                                          > >> > voltages and such, the green covering began to burn through exposing
                                          > >> > the
                                          > >> > copper traces beneath. So I got out the clippers and clipped it loose
                                          > >> > from
                                          > >> > the board, so that I could remove each lead individually. This worked,
                                          > >> > but
                                          > >> > it tore up some of the pads in the process. I intend to replace it with
                                          > >> > this chip because it is available locally (and I don't think going SMT
                                          > >> > again is going to make life any easier):
                                          > >> > http://www.nteinc.com/specs/700to799/pdf/nte778a.pdf
                                          > >> >
                                          > >> > --- In softrock40@yahoogroups.com, "wfahle" <billfahle@> wrote:
                                          > >> >>
                                          > >> >> Ok, I pulled R16, and it still reads 5v at pin 1. R16 measures out at
                                          > >> >> 10k
                                          > >> >> as it should, but with it pulled there is very little voltage at pin
                                          > >> >> 2.
                                          > >> >> The current, since I can now measure it, across R16 is .24mA. The
                                          > >> >> votage
                                          > >> >> at pin 7 doesn't change either; it's still almost zero. The others
                                          > >> >> besides 2 are unchanged. Pin 2 goes almost to zero vs. the 2.5 it had
                                          > >> >> been reading. I guess R16 becomes part of a voltage divider under the
                                          > >> >> circumstances; I don't understand circuits this complex. So I will try
                                          > >> >> to
                                          > >> >> unseat U6 and see if there is a solder bridge under it from 1 to 8 or
                                          > >> >> something (they are across from each other).
                                          > >>
                                          >
                                        • Alan
                                          ... Subject: [softrock40] Re: Bad chip? Not that one, in any case. ... I do not remember you giving the voltages you see on this chip. 73 Alan G4ZFQ
                                          Message 20 of 28 , Nov 3, 2012
                                          • 0 Attachment
                                            ----- Original Message -----
                                            Subject: [softrock40] Re: Bad chip? Not that one, in any case.


                                            > It indicates 5v on pin 1, Just like the other one in that respect. With power off, I'm currently reading 20.9 Kohms between pin 1
                                            > and pin 8, which when reviewing the schematic doesn't seem right. In fact the other dual op-amp which seems wired similarly is an
                                            > open circuit between those pins, giving me more confidence that this is the problem. I'm reading 11Kohms between 8 and 2 on U6,
                                            > which is probably where the 20.9 is coming from adding R16 (which spans 1 and 2). Any ideas anyone? Clearly there is a short
                                            > somewhere, and not a bad chip after all.
                                            >


                                            I do not remember you giving the voltages you see on this chip.

                                            73 Alan G4ZFQ
                                          • wfahle
                                            I am giving continuity checks now. I was reading 5v on pin 1, which was the original problem that made me suspect the chip was bad. In fact it looks like R15
                                            Message 21 of 28 , Nov 3, 2012
                                            • 0 Attachment
                                              I am giving continuity checks now. I was reading 5v on pin 1, which was the original problem that made me suspect the chip was bad. In fact it looks like R15 is shorted to ground between it and C6+. That is not indicated in the schematic, so I'm now pulling R15.

                                              --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                                              >
                                              >
                                              > ----- Original Message -----
                                              > Subject: [softrock40] Re: Bad chip? Not that one, in any case.
                                              >
                                              >
                                              > > It indicates 5v on pin 1, Just like the other one in that respect. With power off, I'm currently reading 20.9 Kohms between pin 1
                                              > > and pin 8, which when reviewing the schematic doesn't seem right. In fact the other dual op-amp which seems wired similarly is an
                                              > > open circuit between those pins, giving me more confidence that this is the problem. I'm reading 11Kohms between 8 and 2 on U6,
                                              > > which is probably where the 20.9 is coming from adding R16 (which spans 1 and 2). Any ideas anyone? Clearly there is a short
                                              > > somewhere, and not a bad chip after all.
                                              > >
                                              >
                                              >
                                              > I do not remember you giving the voltages you see on this chip.
                                              >
                                              > 73 Alan G4ZFQ
                                              >
                                            • wfahle
                                              Found the problem. See other thread.
                                              Message 22 of 28 , Nov 3, 2012
                                              • 0 Attachment
                                                Found the problem. See other thread.

                                                --- In softrock40@yahoogroups.com, "wfahle" <billfahle@...> wrote:
                                                >
                                                > I am giving continuity checks now. I was reading 5v on pin 1, which was the original problem that made me suspect the chip was bad. In fact it looks like R15 is shorted to ground between it and C6+. That is not indicated in the schematic, so I'm now pulling R15.
                                                >
                                                > --- In softrock40@yahoogroups.com, "Alan" <alan4alan@> wrote:
                                                > >
                                                > >
                                                > > ----- Original Message -----
                                                > > Subject: [softrock40] Re: Bad chip? Not that one, in any case.
                                                > >
                                                > >
                                                > > > It indicates 5v on pin 1, Just like the other one in that respect. With power off, I'm currently reading 20.9 Kohms between pin 1
                                                > > > and pin 8, which when reviewing the schematic doesn't seem right. In fact the other dual op-amp which seems wired similarly is an
                                                > > > open circuit between those pins, giving me more confidence that this is the problem. I'm reading 11Kohms between 8 and 2 on U6,
                                                > > > which is probably where the 20.9 is coming from adding R16 (which spans 1 and 2). Any ideas anyone? Clearly there is a short
                                                > > > somewhere, and not a bad chip after all.
                                                > > >
                                                > >
                                                > >
                                                > > I do not remember you giving the voltages you see on this chip.
                                                > >
                                                > > 73 Alan G4ZFQ
                                                > >
                                                >
                                              Your message has been successfully submitted and would be delivered to recipients shortly.