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Re: [softrock40] Re: Si570 desoldering tips

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  • Francis DUPONT
    Hello Pete and All, ... late. ... parts. ... tool ... infrared ... You are right, It is a good method. But in the case of the Si570, I had proposed a
    Message 1 of 20 , Feb 15, 2010
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      Hello Pete and All,

      On 2/15/2010 Pete NI9N wrote:

      >I just noticed this post, so I apologize for being a couple of weeks
      >I have a technique that works very well for unsoldering surface-mount
      >You will need a hot air tool, I use a Weller Portasol butane soldering
      >with a hot-air blower tip. You will also need an electric griddle, which
      >you can get for about $20 at any discount store. You may want an
      >thermometer from Harbor Freight Tools or similar.

      >Use the griddle as a hot plate to preheat the PCB. You'll have to watch
      >the temperature to avoid damaging through-hole parts, this is where the
      >thermometer comes in. When it reaches the desired preheat temperature,
      >apply hot air. The solder holding the part you want to remove should
      >melt almost instantly, and you can lift it right off. If you're
      >replacing it, just place the new one while the PCB is still hot.
      >More hot air to reflow the solder.

      >Make sure you use a good hot air tool, NOT one of the little butane
      >torches from harbor freight or similar, and use the hot air tip, NOT
      >the blowtorch tip. You should see no flame.

      >You can use an electric skillet instead of a griddle, but the griddle
      >is easier to use because it doesn't have the sides.

      You are right, It is a good method. But in the case of the Si570,
      I had proposed a MacGyver's style solution:

      On June 5 2008, in message # 21978, I wrote:

      > It happens that I have soldered mine this week. But before soldering,

      > I have devised a tip to unsolder it, just in case!

      > So here is the story:

      > The goal is to solder the Si570 at a small height (0.5mm for ex)
      above the board.

      > 1 - Put a small drop of solder on each of the 8 pads of the Si570.

      > 2 - Make a U shape with a piece of .05 mm wire. I took 2 inches of

      > wire wrapping wire (30 AWG/0.5 insulation diameter).

      > 3 - Put the U on the board, place and solder the Si570.

      > 4 - Remove the wire.

      Here use a monospaced font(fixed-width) like Courrier New etc.

      > ------X------
      > | |
      > X X
      > ____| |_______________X <- wire soldered on a
      > / | | pad or PCB track
      > | X Si570 X to avoid too
      > \____| |_______________X <- much move
      > | |
      > X X
      > | |
      > ------X------

      > "If" I have to remove the chip, I will place a piece of magnet wire

      > (30 AWG for ex) under it and unsolder one pad at a time by moving the

      > wire while the solder is melted. A well known solution.

      > (Once more it will be a good idea to fix one end of the magnet wire

      > by soldering it on the board.)

      As it costs nothing, I can't say it is my just my $.02 ... 73

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