De soldering - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: January 05, 2012, 05:39:49 pm
content: Hi I have just come across a problem I have not encountered before in de-soldering components. I needed to replace the power jack socket on a Dell laptop, The socket had been arcing badly and eventually the power ceased to flow on take down the center pin was completely without out solder and there was just a black mess the other pins the solder would not melt with any soldering iron that I had. Before any one says use a bigger iron the Biggest iron that I have is 240 watt even that would not melt the solder. At this point I realized that the most likely cause was that under the effects of the arcing the solder and the copper on the board had combined to form a lead/tin bronze this would melt at above 600 deg C. I decided that using the TIG welder to melt the solder would not be an option, In the end I had to resort to brute force and destroy the jack socket removing as much as I could in pieces, I then milled the slots out with a diamond burr. Has any one else had a similar problem and how have the solved it as milling the board is to my mind not ideal apart from anything else the slots that the pins go into end up wider and if there was any plating through of the holes it is no longer there.

author: robrenz
author_rank: Super Contributor
timestamp: January 05, 2012, 06:19:17 pm
content: The black mess was probably thick oxides that are verynonthermally conductive. Cleaning, fluxing and adding a lot of fresh solder to get good thermal transfer first often helps.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: January 05, 2012, 07:31:35 pm
content: Quote from: robrenz on January 05, 2012, 06:19:17 pmI sing that. Its problem in oxide there, not in any alloy creation. Just scraping the solder little bit will help

author: G7PSK
author_rank: Super Contributor
timestamp: January 05, 2012, 08:42:08 pm
content: I had tried that first a good scrub with a brass wire brush and lots of fresh solder. Just did not work, I have been in the metal bashing business for years involving all kinds of joining techniques.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: January 05, 2012, 09:02:01 pm
content: Quote from: G7PSK on January 05, 2012, 08:42:08 pmUse that brass brush to scrub on top of that solder and apply soldering paste in the end to the solder. Then bring your soldering iron with clean tip and fresh melted solder, it will work.However im not sure will the laptop work anymore after it has been attacked with 240 W soldering iron and possibly a TIG gas welder?

author: G7PSK
author_rank: Super Contributor
timestamp: January 06, 2012, 08:55:23 am
content: I decided against the tig set cant use HF start near electronics and one tends not to get such a clean arc start with lift tig any way even set to the lowest amps the tig would bow a hole clean through the copper foil need special equipment for that you can get but it costs a fortune. The milling out with the diamond burr worked. I am sure that what happened was that some of the copper from the pins or tracks had mixed with the solder and formed bronze.

author: project
author_rank: Contributor
timestamp: January 06, 2012, 01:45:21 pm
content: I've fix dozens laptops with power jack problem, never been so hard. most time, you don't even need replace that jack. re-solder it is more than enough.for removal, Clean it up a little bit, 40W sodering gun with 350 C degree with desoldering tool, or just power desodering gun, will works fine. if u can't melt solder on MB. put a little rosin core 63/37 solder on, it'll will greatly lower the melt temp for those Pb free solder. MB is multi-layer board, heat transfer is much faster than single/double layer board. U need more patiant not tig welder to do soldering and de-soldering.