Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Lefteris on April 01, 2008, 01:21:46 AM
-
Hello all,
continuing my experimenting in this new field I bought a cheap desoldering pump and went about trying to desolder. Contrary to the soldering process which was with the help of many videos/tutorials easy to comprehend I can't manage to desolder anything from an old no longer working obviously Graphics Card I found lying around my house.
The components are soldered into the board so neatly (since it's done by a factory's robotic arm I guess) that I can't seem to melt the solder and suck it with the pump completely. Is there something I am missing? Maybe I am not supposed to try and desolder stuff from old graphics card or something? Or is the pump not a good way to desolder?
P.S: Also I noticed that it is quite hard to remove lumps of solder which have gone into the pump, after sucking, it was actually so hard that I thought I had broken the pump for a moment there :P
-
I think most manufacturers put some kind of coating on the joints, making it hard to melt the solder.
-
You can also try de-soldering braid which is lots of thin wires braided together. Put in on the joint and then the soldering iron on top. When the solder melts it is soaked into the braid. Obviously, unlike the pump, you can only use the braid once so its only worthwhile if the thing you are recovering is worth more than the braid.
-
What parts are you trying to desolder from the graphics board? Certainly really small parts, you just need tweezers or something to poke at the part as you loosen it's joints.
-
try adding solder to the joint before desoldering it... sometimes that helps. I do that more often than not
-
I tried desoldering some capacitors, since I thought they would be big enough to desolder easily. I did use a toothbrush and isopropylic alcohol too. Also added solder to the joint to make it easier to desolder. Nothing worked >_<.
I guess I am not supposed to desolder stuff from another board or something. I hope if I make a mistake in soldering I don't get the same difficulties like this time :P
-
I hope if I make a mistake in soldering I don't get the same difficulties like this time
You won't, It's easier with your own stuff.
-
P.S: Also I noticed that it is quite hard to remove lumps of solder which have gone into the pump, after sucking, it was actually so hard that I thought I had broken the pump for a moment there :P
You can pull the entire tip off the bulb.
-
Yeah? Oh thanks, I would not have tried that alone since I am afraid of handling these new for me tools. Now I will try it :)
In other news my first soldering got ... well ... messy. Except from the last 6 pins I could not seem to be able to apply the solder to only one hole ... it went to other holes some times forming connections which were not supposed to exist! :(
I think I need a smaller solder tip, and I also think I need new male header pins and a new IC socket :P since I screwed up ... I will try de-soldering the whole thing, but maybe buying new stuff and starting again would be wiser since I kind of melted the plastic from the male header pins .... exposed it for too much time to the iron's heat I presume.
-
practice makes pefect
also, always buy like 5 more parts then you need when dealing with connectors and sockets ( inexpensive parts)
its always good to have extras
-
My first attempt was using an old 25 Watt iron with a 'traditional' tip. I managed to keep burning the copper caps off the perf board and blobbing solder everywhere.
Am now having a lot more success with an 18Watt iron with the 'needle like' tip.
-
you want like a 40 watt iron. there is a really good soldering video posted on this forum somewhere see if you can find it and watch it.
-
here is the topic with the video
http://www.societyofrobots.com/robotforum/index.php?topic=1587.0 (http://www.societyofrobots.com/robotforum/index.php?topic=1587.0)
-
If its just a cheap soldering iron, you will need to keep unplugging it regularly otherwise it will get too hot, I suspect this is why the solder pads are coming off the per board
-
Thanks for the replies people ! :)
As for the soldering iron it is a 40W Weller, I was told it is an okay soldering iron for start
-
Also, if you desolder a lot on one copper pad it seems like it comes off.
-
Well I managed to make the whole circuit shown in the tutorial, now I only need to adjust it to add the H-bridge to control the 2 DC motors. But now I'll stop since the fumes from the solder made me feel funny :P
By the way does anyone know if the 2 wires from each DC motor matter? I mean is one '+' and one '-' ? Does it matter? Since I the motors I found in the toy RC car, don't have anything engraved on them.
-
Well I managed to make the whole circuit shown in the tutorial, now I only need to adjust it to add the H-bridge to control the 2 DC motors. But now I'll stop since the fumes from the solder made me feel funny :P
By the way does anyone know if the 2 wires from each DC motor matter? I mean is one '+' and one '-' ? Does it matter? Since I the motors I found in the toy RC car, don't have anything engraved on them.
all you have to do, is that if one motor is turning in the wrong direction , just flip the wires of the motor
search google on how DC motors work for more info
-
Left... Read the motor tutorial on this website.
-
I mean is one '+' and one '-' ? Does it matter?
no.
but the motor will spin a certain direction depending on which way you wire them up