Greetings from a Noob......I have a question :D - Page 1
Forum section: electronics / general

author: Brucebleo
author_rank: Newbie
timestamp: May 14, 2012, 07:56:27 pm
content: Ok so I am a pc nerd.....have been since well.....erm....since the days of the BBC Micro and other such antiquated machines. So I am at the point where I am ready to take the next logical step and repair the hardware and not just the software issues as I have been for many years.So I grabbed my old laptop that died on me due to my missus tripping over the power lead and destroying the DC jack.I watch a few vids......seems simple enough....I had done a bit of soldering at school so I picked up a few bits. A nice Duratool desoldering gun and an Atten 8586 hot air rework station.I watched tonnes of youtube vids while waiting for Mr Fed Ex including Dave's soldering tutorials....so I am pretty confident.I get some old broken optical mouses and practice.....Awesome!! solder.....desolder....solder again....no prob.So I pull out my laptop mobo.....try to desolder....not happening.....it's soldered on both sides. So I google and they recommend I snip the legs and clear the holes out after. Which I succeed.....but NOTHING and I mean NOTHING will let me clear the solder holes out.......I have tried everything short of buying a dremmel.......Help me please before I pull my hair out

author: IanB
author_rank: Super Contributor
timestamp: May 14, 2012, 08:04:48 pm
content: I've heard of this kind of problem before.The simplest possibility is that there is so much copper on the circuit board it is conducting the heat away from the iron faster than the solder can heat up to melting point. A more powerful temperature controlled iron may be of help in this situation. Also, put a little molten solder between the iron and the board to help conduct the heat from the iron. Maybe even flood the area with fresh molten solder and then wick it or suck it away.A second possibility, that I'm not sure about, is that they used high melting point solder for that part. They might have done that for mechanical strength, or they might have done it so they could solder other parts later in an oven without the DC jack falling off.

author: pickle9000
author_rank: Super Contributor
timestamp: May 14, 2012, 08:27:28 pm
content: In terms of speed, use a pin vise and drill bit. You need to be very careful not the damage the thru hole if it's a multi layer board.Inability to remove solder is usually temp or mass. A fatter tip, fresh solder an more heat but too much heat = damage.Most hobby shops that sell model trains will have a pin vise and the drill bits available as a kit. 30 seconds worth of gentle turning and you will be through....mike

author: G7PSK
author_rank: Super Contributor
timestamp: May 14, 2012, 08:54:01 pm
content: Many people just snip of the old power socket and then cut down the legs on the new one and solder to the surface, You can also try getting a piece of stainless steel wire and push the old pin out while melting the solder. Wants to be stailess steel as lead solder does not stick to it very well so you will be able to pull the wire out.

author: Brucebleo
author_rank: Newbie
timestamp: May 14, 2012, 08:56:51 pm
content: Yup....I did think of that.....however it's a slotted solder hole and not a round one.....it also has the remains of the old dc jack leg still in it.I have tried heating one side while using a desolder gun on the other....I have tried mixing the lead free with regular solder....I have tried using tweezers to pull on the legs while heating with my air gun......I have tried removing all solder.....adding more solder....I have even tried poking them out with my pointy tool thingies....NOTHING!!! lolBUT all my test attempts on scrap pcb boards work great.....I can desolder smd chips....I can also reflow the chips back on.....But still nothing......

author: Mint.
author_rank: Frequent Contributor
timestamp: May 14, 2012, 09:05:13 pm
content: A photo would be handy

author: Brucebleo
author_rank: Newbie
timestamp: May 14, 2012, 09:15:33 pm
content: Okiedokes I will upload one after my din dinsbut I am pretty ashamed as I have pretty much beaten the damn thing up and it's doesn't look took tidy anymoreBUT in my defence using Daves techniques was able to remove and replace various other components from through hole and smd with no problem at all and so I have been a bit more brutal with this.....probably through frustration though....

author: IanB
author_rank: Super Contributor
timestamp: May 14, 2012, 09:20:17 pm
content: I think you have encountered that bane of the electronics repair technician, the special unmeltable kind of solder. After all, if it won't melt with the heat of your soldering iron, it certainly won't melt with the resistive heating of 5 amps flowing through it from the DC jack...

author: Kremmen
author_rank: Super Contributor
timestamp: May 14, 2012, 09:30:29 pm
content: Probably soldered using one of the RoHS shits, of which there are numerous different recipes. That combined with big ground and voltage rail planes can make things awkward.Try adding a liberal dose of regular 60/40 or 63/37 Sn/Pb solder. Melt a good drop on the tip of your iron and use that to link the tip heat to the component as well as dilute the RoHS solder. You may have to repeat adding and wicking (or vacuuming) away several times but that should work better.Sorry, you already tried that. Didn't spot it the first time around. Preheater next

author: pickle9000
author_rank: Super Contributor
timestamp: May 15, 2012, 02:03:48 am
content: Here's what I'd use if it's being bad. That's a 1/4 inch tip....mike