[Elecraft] K3 - SMT mods

[G4ILO]

Dave G4AON wrote:
> 
> David
> 
> I just used a 12 Watt Antex soldering iron type M, Maplin part number 
> YU90X. They come with a pointed bit as standard. You also need solder 
> wick (or Soldamop) Maplin part number N58AL and stainless steel tweezers.
> 
> Working on the K3 might sound a little daunting, but one of my 
> technicians used to work on SMD parts in his previous job and told me 
> the easy way to work on them for changing the odd part or two...
> 
> 1. Using the solder wick, remove the solder from both ends of the 
> resistor/capacitor.
> 2. The joints should look "dry", holding the component in the tweezers 
> heat one end with the soldering iron and lift that end slightly, then 
> warm the other end.
> 
> This was the first time I had worked on surface mount, although I have 
> more than 20 years experience of PCB work from a previous job.
> 
> 
I am in no great hurry to do any mods, since the lack of them is not making
any noticeable difference to my K3. My concern is that when trying to use
the desoldering braid, enough solder will remain to keep the part in place,
and one will end up doing it too many times and eventually lifting a trace.
One list member already reported doing that.

I don't have any scrap boards with SMD components to experiment on, but
since all that is needed is to remove a couple of parts, I planned to try
this:

Using a bit of stiff copper wire, wind a tight coil of 2 or 3 turns so that
it is a tight fit on the end of the soldering iron bit, and turn the ends of
the coil so that I end up with a bit with two prongs extending forward of it
for a few mm, spaced apart by the width of the SMD part.

When the iron is heated up, it will heat the copper wire extension as well.
I will then apply the bit so that the wire prongs are either side of the
part to be removed. The idea is that the solder will be melted on both sides
of the SMD part simultaneously and the part can immediately be moved. If
necessary, the solder wick can then be used to clean up the area.

Does anyone think this would work?

-----
Julian, G4ILO  K3 s/n: 222 K2 s/n: 392
G4ILO's Shack: www.g4ilo.com
KComm for K2/K3: www.g4ilo.com/kcomm.html
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