How to desolder large power connector and lead free solder - Page 1
Forum section: electronics / beginners

author: j_omega
author_rank: Contributor
timestamp: November 12, 2018, 01:58:20 pm
content: I have have a large power connector that I am trying to remove from a piece of consumer electronics. This is proving difficult because it uses lead free solder and is tied to very large power and ground planes. I have a Hakko FX-888D which I turned up to 730° without success. I tried using my reflow hot air gun and still no luck. The power/ground planes dissipate the heat too well. Any suggestions?

author: EPTech
author_rank: Regular Contributor
timestamp: November 12, 2018, 02:16:50 pm
content: Hi,You need an infrared under heater to pre-heat the board from underneath. I usually heat them up to 150°C. But you can also pre-heat the board in a regular oven. It will make (de)soldering that much easier.Happy soldering...

author: drussell
author_rank: Super Contributor
timestamp: November 12, 2018, 02:40:47 pm
content: The initial temperature of your tip cannot overcome the fact that you're limited by the total wattage heat output of the iron when you start dumping all your heat into a large thermal mass. You either need a beefier iron that produces more heat or, as suggested above, you can try pre-heating the board to add some pre-heat into whatever you're trying to desolder.One trick that may work is that if you have a second iron, even a non-temperature controlled regular type one, you can stick it on therealsoto pump more total heat into the job. You just need some dexterity (or a helper) and hold your tongue atjuuuuustthe right angle.At times like this I would probably just reach for my ancient, big, fat Weller 80 watt (looks similar to the SP80N or the SPG80L stained glass iron, but much older with a black handle, no idea what model it is, probably something like SP80, though) or even just grab the good ol' Weller 8200 100/140W gun. In situations like this you're less likely to cause damage by using an "excessively large" iron and going in there and quickly heating the joint with the ginormous beast rather than sitting there cooking everything around it for ages while you try to heat it up with a small iron.

author: j_omega
author_rank: Contributor
timestamp: November 12, 2018, 04:09:09 pm
content: Im thinking that maybe I should pick up a 150W iron like this Hakko 551V-V12. Any thoughts?https://www.hakkousa.com/products/soldering/matchless-heavy-duty-soldering-irons/150w-heavy-duty-soldering-iron.html

author: mvs
author_rank: Frequent Contributor
timestamp: November 12, 2018, 07:00:03 pm
content: Quote from: j_omega on November 12, 2018, 04:09:09 pmTip form of this soldering iron is bullshit. It can be used to torture somebody, but not for soldering.Look for an iron with thick chisel tip. It can carry a lot of solder and has good heat transfer capability.

author: helius
author_rank: Super Contributor
timestamp: November 12, 2018, 08:01:37 pm
content: Quote from: mvs on November 12, 2018, 07:00:03 pmYou're not kidding, the vendor actually says "It can also be used as a branding iron, or a cattle prod."

author: Kasper
author_rank: Frequent Contributor
timestamp: November 12, 2018, 08:12:35 pm
content: Extra large chisel tip (about 4mm) and lots of solder might do it

author: ratboy
author_rank: Newbie
timestamp: November 21, 2018, 03:56:41 am
content: 730 is only 388 degrees celsius.Try bumping it up to 450 degrees celsiusand also melt/add lots of leaded solder to the joint to start it melting.