MessageHi Kareem

I am assuming that you are removing a component from the circuit board.  The
circular or square pad surrounds a hole drilled through the circuit board.
The sides of the hole are plated with metal.  The component lead passes
through the hole and solder fastens it to the pad on either side of the
board and to the plating on the sides of the hole.  The pad is actually
copper underneath.  What you see on the surface is a solder coating on the
copper.

The danger with unsoldering components is that the copper pad substrate may
lift off the PCB board if the pad is heated too hot and/or too long.  If
this happens, you are in deep trouble.

If you are real careful, you can heat the component lead, and when the
solder liquifies, gently pull the component lead out through the hole.
Remove the lead in stages rather than let the pad get too hot.
Alternatively, you can buy a device called a Soldevac that uses a brief
burst of vacuum to suck molten solder out of the component lead hole.  If
done right, its quick and you are left with a dry hole which the component
will almost fall out of.

Hope I interpreted your question correctly and that this helps.

Ron

  -----Original Message-----
  From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of Kareem
  Sent: Tuesday, February 05, 2002 1:41 PM
  To: PSN
  Subject: soldering pad tips...


  Hi all,

  I'm preparing to unsolder a pad on a circuit board and I'm not exactly
sure where unsolder. If anyone is familiar with electronic circuitry, please
let me know. I seems that I just need to remove the solder from a particular
pad - the only problem is that I'm not certain what the pad actually looks
like. Any links or websites with pictures on how to unsolder this would be
greatly appreciated.


  Thanks,

  Kareem






Hi 
Kareem
 
I am 
assuming that you are removing a component from the circuit board.  
The circular or square pad surrounds a hole drilled through the circuit 
board.  The sides of the hole are plated with metal.  The component 
lead passes through the hole and solder fastens it to the pad on either side of 
the board and to the plating on the sides of the hole.  The pad is actually 
copper underneath.  What you see on the surface is a solder coating on the 
copper.
 
The 
danger with unsoldering components is that the copper pad substrate may lift off 
the PCB board if the pad is heated too hot and/or too long.  If this 
happens, you are in deep trouble.
 
If you 
are real careful, you can heat the component lead, and when the solder 
liquifies, gently pull the component lead out through the hole.  Remove the 
lead in stages rather than let the pad get too hot.  Alternatively, you can 
buy a device called a Soldevac that uses a brief burst of vacuum to suck molten 
solder out of the component lead hole.  If done right, its quick and you 
are left with a dry hole which the component will almost fall out 
of.
 
Hope I 
interpreted your question correctly and that this helps.
 
Ron
 

  
-----Original Message-----
From: psn-l-request@.............. 
  [mailto:psn-l-request@...............On Behalf Of 
  Kareem
Sent: Tuesday, February 05, 2002 1:41 PM
To: 
  PSN
Subject: soldering pad tips...


  
Hi 
  all,
  
 
  
I'm preparing to 
  unsolder a pad on a circuit board and I'm not exactly sure where unsolder. If 
  anyone is familiar with electronic circuitry, please let me know. I seems that 
  I just need to remove the solder from a particular pad - the only problem is 
  that I'm not certain what the pad actually looks like. Any links or websites 
  with pictures on how to unsolder this would be greatly 
  appreciated.
  
 
  
 
  
Thanks,
  
 
  
Kareem