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69691Re: [softrock40] Re: Bad chip?

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  • Sid Boyce
    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
      
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