Surface mount soldering info...

I do it ...
- You need a hot air generator. You can use a hot air paint stripper  with a electronic regulator ( triac based regulator). Make many try before to adjust temperature ...
-You need "liquid" (pastry?) soldering (CMS soldering) . To determine quantity, you can use a hypodermic (disposable) syringe.
- Clean mount surface (circuit board) : use a ink eraser and after acetone solvent.

-A micro iron solder ( From Radioshack ) and a magnifying glass coulb be useful.
Better, a tool to inspect (examine) negative or slide...

 

Are U sure it's worth the effort :)

Well... use the hot air generator at the backside of the PCB's U want to strip for componets - this way U will possibly not burn the chips by excessive heat. Just apply heat until the chis falls off. Help them with a pincher...

Resoldering... U ´will certainly need some fluss, to ensure that soldering is possible on the more or less coroded soldering pads.

It can be done - I have change quite a lot of Motorola 68000 FPGA, or whatever they are called in SMD style

Go to
http://www.esisupply.com
to their line sheet, where there will be some links to manufacturers of SM equipment and supplies.  Some may have dealers in UK.

The blow gun is good for part removal,
but will cause heat damage if too hot.

You use thick flux to hold the parts in place while you solder.
You probably should not try the combination solder/flux, it requires too much control.
You will need a good cleaner/defluxer for afterward.  Can you get TCE in UK?
You need an iron with a very pointed tip, very good close vision, steady hands, tiny solder, and patience.

Oh, and something called "Solderwick", which is a sort of braided copper to use as a sponge to pick up little beads of excess solder.

I am not worried about getting the chips off the 1mb simms, they are SOJ type and I just score along the solder line a few times then crack them off by sticking penknife blade underneath, done that many times for salvaging 40 pin SOJ's to upgrade graphics cards, no heat=no heat damage and the pins have anough spring that I have never done mechanical damage.

It is the soldering them onto the 4mb boards that I am looking for a good solution for, I go cross eyed trying to solder that fine and close with a fine tipped iron, and often end up frying the component or lifting the pads off the PCB.


Frache,

Is the solder paste for use with a hot air gun? Around how hot does it need to be to melt?

I don't have a hot air gun, but I have a hair dryer that gets VERY hot for a hair drier, can't bear to hold my hand in front of it, have used it on heat shrink tubing before. At a guess it can get over 100 degrees centigrade when it is on a while. If it needs much hotter than that, I can maybe rig a hot air gun up with toaster parts and a shop vacuum I have that blows. Or a blow torch far away?

Trying to do this cheap, otherwise I may as well buy some 8mb SIMMs. But I have far more time than money.

3rsrichard, I am now in Canada by the way, guess I should note that on my profile huh?

Thanks,

Road Warrior

Thanks Frache, the paste sounds like the way to go, will have to see if I can beg or borrow a hot air gun though, hmmm have a darn great big plumbers soldering iron 75W+ maybe holding that nearby would work, will have to experiment. Thanks.

Road Warrior

Good luck.