IC Removal


In my experience, compared to modern printed circuit boards (PCB), old PCBs are more easily damaged by heat.

Even though I own a temperature controlled, vacuum based, desoldering tool, complete solder removal is not guaranteed.   Often, an IC pin still has significant solder on the component side.   Or sometimes, just a little bit of solder, but enough to retain the pin.   This necessitates application of solder, and another attempt at the desoldering operation.   Each time that a desoldering operation is attempted, the PCB is exposed to more heat.

If I am desoldering an IC, the usual reason is that I have proven the IC to be faulty, or I have determined that the IC is probably faulty.   In those cases, I use the following technique, one that destroys the IC, but aims to minimise heat damage to the PCB.

Using a suitable pair of side cutters, I cut each pin, as close to the IC body as possible. In the photo on the left, for illustration purposes, I show the side cutters being at about 45 degrees in relation to the PCB.  To get the cut as close to the IC body as possible, the cutters are normally perpendicular to the PCB. (BTW: The cutters that I use for this are either a Plato model 170 [PL-170] or a Lindstrom model 8140)

I end up with the pins sticking up in the air.

In profile, each pin looks kind of like this.

For each pin: 1.   I apply some solder to tip of soldering iron. 2.   I place the tip under the hook part of the pin. 3.   I add additional solder (being generous). Heat starts traveling down the pin into the solder joint.

When the solder in the joint liquefies, I move the soldering iron's tip upwards, lifting the pin out of its hole. This works, even if the hook on a pin is nowhere near as pronounced as in the drawing.   The solder between the iron's tip and the pin, helps holds them together. Sometimes, to assist this, I maintain the application of the solder stick (i.e.  there is pressure on the pin from both sides). I can usually remove each pin in about 1 to 2 seconds.  Pins tied to ground or voltage lines usually take longer, and sometimes I will turn up the heat on the iron for those.

When the pin is removed, the quantity of remaining solder will vary from hole to hole. Irrespective of how (soderwick, desoldering tool, etc.) I plan to empty the hole of solder, I have always found it to be easier if the solder in the hole extends out past the hole itself, per the (exaggerated) lower drawing on the left. Therefore, if the remaining solder looks like the upper drawing on the left, then I add more solder.

My preference is to use a temperature controlled, vacuum based, desoldering tool. It's very quick. (BTW: Before activating the vacuum, allow enough time for all of the solder to liquefy.)