AVR-Chat

I will look into drag soldering!  I have the binocular loupes 
covered.  I have a really nice set of loupes.  I can see the detail 
well below my ability to manipulate it, and they have good field of 
view.

THe soldering is the trick.  I will definitely try it with old 
computer cards.  I have enough of those!!!

-Tony

--- In AVR-Chat@yahoogroups.com, Don Ingram <don@l...> wrote:
> 
> > One alternative already suggested is an adapter such as 
a "surfboard" 
> > or similar.  The problem is tha amount of square inches required 
for 
> > the conversion from smt to 0.1 spacing pins.  All those pins 
take up a 
> > huge amount of space!!!!
> > 
> > I just do not see how I can reliably solder all those tiny SMT 
> > connexions.  I would have to use my loupes for sure.  ALso a new 
iron 
> > with the 1/64" tip....
> > 
> 
> Tony,
> 
> Hand soldering a TQFP is dead simple...  as long as you have the 
knack.
> Have a look at the app notes on the Metcal site for the mini-hoof 
tips & 
> their use in drag soldering. Pace may also have an app note for 
their 
> 'mini-wave' tip series. Googling 'drag solder' brings up a 
squillion hits.
> 
> Once you have an idea of the drag soldering technique as used with 
blade 
> & concave tips you will find it quite easy to work with these 
packages. 
> It will take a little practice but you can get this by removing 
and 
> refitting packages on old computer cards. Pull them off with a 
paint 
> stripper gun & then clean up & refit them with your drag 
technique. 
> Using controlled heat it is quite possible to do this cycle > 20 
times 
> on an FR4 PCB without lifting tracks.
> 
> There are a number of concave tips available for common brands of 
iron 
> these days. There was a video of the process on the net ages ago 
but I 
> don't know where ( too much red is bad for the head Ned! )
> 
> Key things are:
> 1. Good heat control
> 2. Tons of flux
> 3. Good vision - use bino glasses or even better a cheap stereo 
microscope
> 
> It is much faster to fit a TQFP than it is to hand solder a 64 pin 
> adapter package using thru-hole.
> 
> 
> Cheers
> 
> Don