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Re: [softrock40] Re: Cooked IC?

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  • geoff theasby
    I agree. I worked in satellite communications for 15 years. You MUST take ESD precautions all the time. Use an earthed bench mat, or build the circuit on an
    Message 1 of 6 , Apr 28, 2008
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      I agree.
       
      I worked in satellite communications for 15 years.   You MUST take ESD precautions all the time.
      Use an earthed bench mat, or build the circuit on an earthed metal plate.
      I also built nearly 1000 C-MOS PCBs as a sub-contractor to an electronics company, to my knowledge, none of them failed due to ESD problems.
       
      Regards
      Geoff, G8BMI
       
      ----- Original Message -----
      From: Ray
      Sent: Monday, April 28, 2008 5:28 PM
      Subject: RE: [softrock40] Re: Cooked IC?

      It can most certainly do that much damage – it can blow holes in the substrate and circuits and even fuse them together.  ESD precaution is a serious matter and must be followed anytime you handle components and circuits.  It is also possible to setup a latent failure with ESD so if it doesn’t fail immediately it may later in time.  I have worked with solid-state technology 45 years and always practiced ESD safety procedures; this is not a new science or phenonema.  I have seen space-program devices and multi-million dollar computers fail due to ESD.  Some of us consider certain types of IC designs as ESD proof and that is pure none-sense, some devices are hardier than others but in the modern world of micro-circuits nothing is 100% immune and most are not even close to being able to survive a static zap.   Here is are some good pictures of what might happen due to ESD. 

       http://www.desco. com/PPT/ImagesOf ESDDamage. ppt#268,1,

      So it can and does happen – 100% caution is the only way keep the risk low.

      I know that several people will jump on this mail with stories about static survival and how certain devices are immune and when a device is in the board it is safe.  All I can say is that if you ignore the ESD procedures and get away with it count your self fortunate. 

      73,  Ray,  N0FY

      SKCC # 3704

      "It's not the years in your life that count.  It is the life in your years."   Abraham Lincoln


      From: softrock40@yahoogro ups.com [mailto: softrock40@yahoogro ups.com ] On Behalf Of w7qjq
      Sent: Sunday, April 27, 2008 11:45 PM
      To: softrock40@yahoogro ups.com
      Subject: [softrock40] Re: Cooked IC?

      --- In softrock40@yahoogro ups.com, "Grant McDuling" <mcduling@.. .>
      wrote:
      >
      > Hi guys,
      > I hit a prob with the softrock 40/80 v6.2 today. I picked it up to do
      > some checks and ... zap... a static discharge. Now if I measure the
      > resistance to ground from the 5V point, I get about 0.04 ohms; near
      as
      > dammit to a short. I guess I have cooked one of the ICs.
      >
      > Any ideas how I can tell which one?
      > Grant VK4JAZ
      >

      Apply +5V from a supply that will source a few hundred mA to the +5V
      test point for a few seconds.... the part that gets hot is the one
      causing the problem.
      However... I am not convinced that a static zap would cause such a low
      resistance. Maybe a simple short from a solder splash or similar?

      73, Sid W7QJQ
      Oklahoma


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