How To Desolder Components

Introduction

Sometimes PC technicians need to replace electronic components, such as electrolytic capacitors and connectors. The most common case is when you have a motherboard were the electrolytic capacitors leaked.

Desoldering and replacing components is not as easy as soldering them. The main problem is that printed circuit boards, especially motherboards, have several layers. You see only two layers (called “solder layer” and “component layer”), but there are other layers inside the printed circuit board, like a sandwich. The holes where the components are soldered to are metalized and serve not only to hold the component, but also to make the electrical connection between the two visible PCB layers and the internal PCB layers, which are not visible. If you make a wrong move while trying to remove a component, you may break the connection between the hole and the internal board layers, destroying your board.

In this tutorial we will explain you how to correctly desolder components, with several practical tips on how to get the best result.

Needed Tools

To desolder components you will need the following tools:

• Soldering iron (25 W or 30 W, don’t use one above this power spec)
• Solder
• Desolder pump (a.k.a. solder sucker)
• Cleaning cloth
• Cleaning sponge
• Small flat-tip screwdriver
• Isopropilic Alcohol (Isopropanol), do not use regular alcohol
• Toothbrush

Figure 1: Needed tools.

Preparation

Turn your soldering iron on and wait for it to get hot (three minutes, more or less). Wet the cleaning sponge and clean the soldering iron tip, making the movement shown in Figure 2. Make sure you repeat the movement until you have covered the entire tip. Some smoke will appear, don’t worry, that’s normal since the sponge is wet.

Figure 2: Cleaning the soldering iron.

During the desoldering process you may need to clean the soldering iron tip again. Every time you see the soldering iron tip with black parts it is time to clean it again.