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Thread: Resoldering- tips from Electrical Engineer

  1. #1
    Join Date
    Apr 2004
    Posts
    517

    Default Resoldering- tips from Electrical Engineer

    Attached are tips from EE with broad expereience in electronic design re "resoldering". A DIY guy who owns plane and other stuff with less demanding reliability reqmts.
    ---------------------------
    Gene,
    I have seen many examples of solder joint failure where high
    current connections are made between printed circuit boards and relay
    points. The current density at such connections is high enough to
    fatigue the solder after a time and cause a "cold" or intermittent
    connection. The best solution would be to use a
    solder sucker to remove the old solder (melted), and then replace with fresh
    solder. The heat and reflow method will leave oxidized particles from
    the old joint that may cause a resistance high enough to cause the same
    problem again.

    The picture in the link you provided shows closely spaced connections
    that may become bridged if you are not very careful with the soldering
    tools.

    http://www.bmwe34.net/E34main/Mainte...trical/LKM.htm

    Radio Shack has the tools you need. A 25-35 watt soldering iron will do the job. They have manual type solder suckers. Both should be less than $15 total. If you don't already have some get a roll of good electrical solder. DO NOT USE ACID COE PLUMBING SOLDER. It will destroy the device. Just take your time and watch that you don't bridge solder to adjacent joints.

  2. #2
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,281

    Default

    see my website below, for that I have included this

    Basic Electronics Soldering & Desoldering Guide -english-

    http://tridem.han-solo.net/auto/erich/auto.htm

  3. #3
    Join Date
    Apr 2004
    Location
    DFW
    Posts
    372

    Default

    As an EE major I must say that this should be common knowledge for most people who have toyed with electronics for a while. Having an EE degree is a bonus. Wish I had mine.

    Quote Originally Posted by Gene in NC
    Attached are tips from EE with broad expereience in electronic design re "resoldering". A DIY guy who owns plane and other stuff with less demanding reliability reqmts.
    ---------------------------
    Gene,
    I have seen many examples of solder joint failure where high
    current connections are made between printed circuit boards and relay
    points. The current density at such connections is high enough to
    fatigue the solder after a time and cause a "cold" or intermittent
    connection. The best solution would be to use a
    solder sucker to remove the old solder (melted), and then replace with fresh
    solder. The heat and reflow method will leave oxidized particles from
    the old joint that may cause a resistance high enough to cause the same
    problem again.

    The picture in the link you provided shows closely spaced connections
    that may become bridged if you are not very careful with the soldering
    tools.

    http://www.bmwe34.net/E34main/Mainte...trical/LKM.htm

    Radio Shack has the tools you need. A 25-35 watt soldering iron will do the job. They have manual type solder suckers. Both should be less than $15 total. If you don't already have some get a roll of good electrical solder. DO NOT USE ACID COE PLUMBING SOLDER. It will destroy the device. Just take your time and watch that you don't bridge solder to adjacent joints.

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