Desolder resister leg that is connected to the ground

[Rod]

Hello!

How do you guys desolder a resister leg that connected to the ground of a PCB?

Im able to easily desolder a resistor that is in the signal path, however te hardest resistor to remove are the ones that have a leg connected to the ground.

[Jazz P Bass]

One word: Heat.
What solder station are you using?
I use a 25 watt Weller and have never had issues with the ground plane of a PCB.
Now if you are talking soldering to a metal chassis, that will take a whole lot more wattage.

[Rod]

Im using a 30watt solder iron, and the chem-wik its not sucking the solder.

[Dave H]

Im using a 30watt solder iron, and the chem-wik its not sucking the solder.

I find that wik works better if I stroke both sides of it with a flux pen before use. Also wet the iron tip with a little fresh solder before applying it to the wik.

[oc disorder]

I have a large old fashioned one that takes about 20 minutes to heat up that I keep for these special occasions. It is a bit hard to maneuver with its large bit but it turns
a large blob of solder into a liquid pool in seconds... I just have to be very careful where I put it down. After wrestling with temperature controlled irons I sympathize with your predicament!
If I'm in a hurry I just clip the old one out leaving some of the wire and try to neatly join the new one to the old.

[Helmholtz]

Many possible reasons:

1) Your desolder wick my be old and oxydized,
2) Your tip may not be clean and well tinned,
3) Your tip may be too small for the job.
4) Your soldering iron may not be able to transfert the heat efficiently and fast enough to the tip. Wattage is not all.

It often works to desolder only the other end of the component and then heat the ground joint and pull the component off (e.g. with tweezers).

Also a little flux might help.
And often a good solder sucker works better than wick, as the wick pulls heat from the joint.

[xtian]

Good 75w soldering stations with adjustable temp are available for under $50. I love mine: https://www.circuitspecialists.com/b...g-station.html

[Enzo]

Your description suggests you are desoldering the resistor by trying to remove all the solder around it. Just heat the joint and pull the resistor wire from it, and THEN go about removing solder from the hole.

[Helmholtz]

^^That, as said above.
Often it's not necessary to remove all the solder. Just re-use it.
Opening the wire hole works best with a solder sucker.

And always add a little fresh flux core solder when desoldering.

[Mick Bailey]

The type of temperature control the iron uses can make a difference. What make and model is your iron? Sometimes a good lower wattage iron can beat a cheap higher wattage one. Some irons have very long warm up times and these often don't have good thermal recovery - the tip cools down and the rate of heat being supplied to the bit can be slower than the heat being conducted away. If you find that you're waiting a long time for the iron to get up to temperature, this may be an indication of poor performance. I find that even with decent fluxed desolder braid it pays to use liquid rosin flux as well. Mostly I use a desolder station but sometimes I do use braid. Some of the worst jobs are where a foot switch is tightly pressed into a double-sided through plated PCB with ground planes on both sides.

For the past 12 years or so I've been using temperature controlled solder stations. I have a 70W Xytronics and have recently switched to a self-build 72W T15 station which has hot swappable bits where the temperature sensor and heating element are built right into the tip. The temperature control is maintained to +/- 1 degree centigrade. The higher wattage of these means a broader range of jobs can be tackled - the job isn't sucking the heat out of the tip to the point where it cools down too much.

For really big jobs such as soldering to the chassis (for example, the brass grounding strip in some Fender amps) I have a 250W iron with a large copper bit and excellent thermal mass. I also use this for can-type caps that have solder tabs that fix them to the chassis.

Different people have their own preferred ways of working. There's no real right or wrong, but getting enough heat to the job and at the same time keeping the temperature constant is important, no matter whether you use braid, a desolder station or solder sucker.

[Rod]

Done, i had other solder iron with variable power from 30 to 130watts, and removed the solder.

Thanks everyone.

[J M Fahey]

You can first melt solder and pull resistor leg, then keep the holeopen for future reinsertion with a wet toothpick.
No need to remove all solder and then reapply same amount.