I get a fair amount of recyclable electronics material. I was just
thinking that I must buy a desoldering apparatus, looking at
ads in a magazine. They are too expensive. So, here is what I did:
Make an IC desoldering tip for your iron. I made mine out of a
heat sink; the type with the straight fins, used for cooling power
amps for example. It turns out that the fin spacing is just good for
DIP ICs.
Cut one out, so that only two fins remain. Also trim the height so
that it is good for 10pin DIPs. Cut off the fins about 2-3mm
from the base. Now, what you are left with is a shallow U channel. The
next thing to do is to cut grooves along the top of the U. Each groove
will fit onto one row of pins of the IC. This operation is the most
critical, so it is better to measure well before cutting in..
This is a quick & dirty tool for removing those valuable ICs from their
nests. You can think of a way to attach it to your soldering iron.
I simply drilled through the iron, and fixed the back of the tool
to the side of the iron with a screw (larger area gives better heat
transfer).
Here is the tool:
I cut the grooves with a razor saw. This gave the low clearance for
better heat transfer. Saw the grooves for the IC pins deep enough
so that the tool can reach down and touch the PCB surface. My first
version only heated the IC pins, and this was not enough for double
sided boards. In my first try, I could remove a bunch of ICs without
damaging the board at all. I used a 30W iron, and it takes about 10sec
for the solder to melt through in a double sided PCB. A larger iron
is of course better. Also, you could file a flat on the side of the
iron, or a groove on the back of the tool to improve heat transfer.
It is easy to make this. It took me about an hour to make it, and
I only used a razor saw and a drill (to drill out the iron, the
heat sink was already drilled and tapped!). Recommended for the
pure DIY guys; "This CD player (typ.) is made out of old computers
I found at the city junkyard"
Removes everything! In the process, it wrecks the board too!
I have removed, PGA packages of more than 130 pins (68030), the ISA connectors from old PC motherboards, all sorts of connectors and large parts... It can be used on multi layer boards. If you get the knack of it, it is possible to remove the part with minimum damage to the PCB (the ISA connectors came off without damaging the board)... It is best to hold the torch tangential to the PCB, and only heat the pins.
It is also possible to remove SMD components. Heat from the other side of the board!
