Replacing components

[cobainlives_05]

To replace components on PCB, how do i get the old ones out?

Thanks

[Samuel]

First, you need to desolder the component. There are a couple common ways to do this: desoldering braid or a desoldering pump. Braid is basically stranded wires, you lay the iron on the glob of solder and the braids simultaneously and hold the braids into it. The solder then flows up the braids and off of the board. The pump is basically just a suction device, heat the solder and then suck it right up into the pump. Both are available at RadioShack. If you can completely remove the solder then you should just be able to pull the component out, but I find that you generally need to pull the component while heating the pads its attached to. Use needle nose pliers to pull the component so you don't burn yourself!

Also don't go too crazy with the iron, as you can end up detaching the copper circuit trace from the board, or potentially damage neighboring components...

[cobainlives_05]

cool, have to go do that then. thanks

[ErikMiller]

I'm a fan of the desoldering pump, myself. Never got too good with the braid. Seemed like I'd saturate a foot of the stuff and then the lead would still be stuck in the hole.

[Peter Snowberg]

I always hated braid until I learned that if you apply some liquid flux to it before-hand, it works quite well. Without the flux, it's useless.

I picked up a desoldering station with a vacuum pump and when it's not clogged, it works amazingly well. For the non-automated solder suckers, there are two styles. the first one is a squeeze bulb with a high heat tip. I have never been happy with these. The second style is a spring loaded syringe. These can work amazingly well.

One tip is to add a little additional solder to the connection before sucking it up. That helps to get more even heat on the joint and it seems to help the liquid solder flow into sucker better because the extra metal keeps the heat in a little longer.

Take care,
-Peter

[cobainlives_05]

What is flux? How much does it cost? And where can i get it?  Can you tell that I'm new to this???

[Peter Snowberg]

$6.65 from http://www.action-electronics.com/kester.htm

This is the first thing that poped up when I googled for "liquid rosin solder flux".

Flux is the stuff in the middle of most solders. It eats oxide and cleans the connection so that the solder can flow easily. There are two basic types, acid, and rosin. You don't want the acid stuff. It will eat circuit boards and component leads unless you clean 100% of it off.

RadioShack sells (or at least used to) a flux in paste form. It works fine too, but the liquid is great. A little bottle like that will last for a long time.

Any time you want to solder something big, a little extra flux cuts the work in half. I wish I knew about it 20 years ago.

Take care,
-Peter

[Paul Perry (Frostwave)]

Sometimes braid works best, sometimes the sucker. What NEVER works is old braid that has tarnished! Also, some braid has flux built n, it is lots better. Plus, I often use a stainless steel dental pick (solder doesn't stic to it) to poke the molten solder out of holes.
Practice on an old modem board before wrcking your fx!!

[Ansil]

can we say heat gun?  also for quick jobs and as long as you can ge to thim. there is an attachment for the ratshak gass solderer  to be a micro flame solderer..  drops parts off the board like crzay