Soldering Trouble. - Page 1
Forum section: electronics / repair

author: VintageTech
author_rank: Contributor
timestamp: August 06, 2014, 08:59:34 pm
content: Hello,Recently I was trying to salvage some components from a vintage PCB. Everything was great until i tried to heat up a joint to remove some solder. The solder melted and I was able to remove most of it, but the component, a DIP package, wouldn't go anywhere. How should I go about getting these components? Should I cut and file the PCB? Should I be tackling this another way?Thank you,VintageTech

author: rob77
author_rank: Super Contributor
timestamp: August 06, 2014, 09:08:54 pm
content: to remove a DIP package you need to heat all pins at once. when the solder on all pins is melted , then just pick the DIP component.hot air is the best for the job, but there are various other techniques to heat all pins - search on youtube , you'll find some related videos for sure.

author: tautech
author_rank: Super Contributor
timestamp: August 06, 2014, 09:09:46 pm
content: IC's can be hard to remove successfully.For repair/replacement one would cut the pins and remove them later.You haven't said what your de-soldering method is.I just use a sucker.But when you have as much solder removed as possible, wiggle each pin in the hope that the remaining can be broken and free each pin in turn.I keep a few different heat solders for component removal.Often one will need to resolder with low temp solder, then re-suck.Persistence should pay off.

author: ju1ce
author_rank: Regular Contributor
timestamp: August 06, 2014, 09:10:22 pm
content: Without theit's major pain as very little residual solder is enough to make the pin stick to the pad (especially with plated holes).

author: mariush
author_rank: Super Contributor
timestamp: August 06, 2014, 09:32:05 pm
content: You can also see how Ian desolders this chip , he also gives some tips that may help you:

author: wagon
author_rank: Frequent Contributor
timestamp: August 07, 2014, 01:04:49 pm
content: Another trick that you can try, use a very hot iron & lots of solder. Use the solder to keep heat and melted solder on all pins at once. Then pop device out of the board. Then clean out the holes with wick or a sucker.

author: rob77
author_rank: Super Contributor
timestamp: August 07, 2014, 02:43:58 pm
content: Quote from: wagon on August 07, 2014, 01:04:49 pma solder blob to de-solder a DIP 40 would be extreme and solder is expensive !a cheap hot-air station (or even a paint stripper on lower temp settings) will do the job of heating all pins at once.

author: SeanB
author_rank: Super Contributor
timestamp: August 07, 2014, 05:04:26 pm
content: Used the paint stripper today. The old Slot 1 Pentium chip did not survive......... The chip did come off, and so did the lid.

author: wagon
author_rank: Frequent Contributor
timestamp: August 07, 2014, 11:17:06 pm
content: Quote from: rob77 on August 07, 2014, 02:43:58 pmI don't do it with devices with more than about 20pins (DIL). I don't always have all of my toys at easy access, so you have to make do with what you have at hand.

author: Richard Head
author_rank: Frequent Contributor
timestamp: August 08, 2014, 12:16:09 pm
content: a solder blob to de-solder a DIP 40 would be extreme and solder is expensive !I think Wagon meant heating ONE row of pins at a time.I sometimes use two soldering irons simultaneously for some stubborn heavy duty parts. It's a bit like using chop stick!

author: Rasz
author_rank: Super Contributor
timestamp: August 08, 2014, 09:50:27 pm
content: Quote from: SeanB on August 07, 2014, 05:04:26 pmslot1 ?? were you trying to desolder cpu from slot1 holder pcb? This is very difficult, 240 pins!find more victims and practice, start with smaller pin countand learn to heat evenly, start with preheating pcb, control temberaturedo not use force

author: geek
author_rank: Unknown
timestamp: August 08, 2014, 10:22:47 pm
content: I know only 2 options: heat all pins at once or use solder sucker

author: Rasz
author_rank: Super Contributor
timestamp: August 08, 2014, 11:22:19 pm
content: Quote from: geek on August 08, 2014, 10:22:47 pmyou can also use big stainless needle to get individual pins

author: SeanB
author_rank: Super Contributor
timestamp: August 09, 2014, 05:53:19 am
content: Quote from: Rasz on August 08, 2014, 09:50:27 pmI found it lying around, and decided to see if I could get the die out. Sadly Intel with this one mounted the die to the heat spreader then did the wire bonding then filled the cavity with epoxy. So not easy to get the die off the epoxy. Did find another Pentium 100 though in a ceramic package that I had delidded years ago, and the solder under the die had corroded finally so the die popped off.

author: jancumps
author_rank: Unknown
timestamp: August 09, 2014, 06:15:31 am
content: In some cases, you can forge a soldering device by folding a copper wire in a rectangle/square form that it can touch all pins of the ic, and wrap the end of the wire around your solder iron's tip.

author: REHAN JOIYA
author_rank: Newbie
timestamp: August 16, 2014, 09:04:14 am
content: There are many ways to pull out components from PCBs. 1. In simple form you can use simple soldering iron(small tip up to 60 W) and manual sucker. 2. Some times you need HOT GUN with specific air pressure & temperature, But in this case you should take more cautious from rubber(melting) components e.g. harness,connectors and tiny components e.g. capacitor, resistors and so on.3.you can use mercury because mercury has greater melting point than solder so you can easilypullout tiny legs of components from PCB. In all cases try lot of soldering paste.4. If you have a special electronic lab: then you have already a soldering plant for pulling and soldering components.

author: rob77
author_rank: Super Contributor
timestamp: August 16, 2014, 10:27:21 am
content: Quote from: REHAN JOIYA on August 16, 2014, 09:04:14 ammercury ? seriously ? where the fuck you've seen using mercury to desolder parts ? mercury is freaking dangerous and it makes amalgams with most of the metals.please stop spreading bullshit on this forum.

author: wagon
author_rank: Frequent Contributor
timestamp: August 16, 2014, 11:06:47 am
content: QuoteHasn't done me any harm.*twitch*

author: SeanB
author_rank: Super Contributor
timestamp: August 16, 2014, 11:57:43 am
content: Seems to not be a worry for the illegal gold smelters here, though they often only live until they are 40 or so in most cases. Not a safe as using another low melting point metal or chipquick to make the original solder either brittle or a very low melting point alloy.

author: wagon
author_rank: Frequent Contributor
timestamp: August 16, 2014, 12:46:06 pm
content: What's in that 'chipquik' stuff?

author: SeanB
author_rank: Super Contributor
timestamp: August 16, 2014, 12:50:28 pm
content: Bismuth IIRC. It alloys with the tin or lead and makes an alloy that is brittle with low yield strength and which also has a large plastic range. Thus you can easily pop a SMD part off, or break a pin free from a through plated hole.

author: ablacon64
author_rank: Frequent Contributor
timestamp: August 16, 2014, 12:55:09 pm
content: Without special equipment, I use low melt solder to help removing big ICs.

author: SeanB
author_rank: Super Contributor
timestamp: August 16, 2014, 01:00:56 pm
content: Oops wrong about Bismuth, there it is Indium, though you probably could use a mix of alloys of Bismuth, Indium, Gallium and NOT Thallium ( toxic stuff) to make a low melting point alloy with tin solders.http://en.wikipedia.org/wiki/Galinstanis an alloy ( or if you use enough chipquik) that will melt at room temperature. Common use is in thermometers to replace mercury, though it solidifies at -19C.

author: kjn4685
author_rank: Regular Contributor
timestamp: September 20, 2014, 09:45:13 pm
content: I use a tweezers iron that works for me.

author: mazurov
author_rank: Frequent Contributor
timestamp: September 21, 2014, 05:51:53 pm
content: If you're salvaging the IC in DIP package cut the pins close to the PCB and later solder to the "stumps" left on the package. If you're fixing a board cut the IC pins close to the package and then heat them up and pull from PCB one by one.For salvaging parts a heat gun works well also. For best results, practice on PC power supplies before pulling parts from multi-layer PCBs and do it outside.

author: TheEnd
author_rank: Contributor
timestamp: September 21, 2014, 10:08:33 pm
content: Quote from: mazurov on September 21, 2014, 05:51:53 pmYep, that's what I do occasionally if I need to get it off the board, but still needs to be reused as it's an odd part, and solder leg to leg.What you can do in a pinch is snip all the legs off the existing chip near the body so they remain in the PCB, trim down the legs on the replacement and solder leg to leg. It's not all that tidy, but it'll work.The other idea to remove a component with basic tools is to desolder each leg with solder braid, and then just flick the leg as it is cooling down to make sure it is free. There should just be enough room to wiggle it a little so you can be sure there's nothing left sticking it.It's a long job, but you should be able to save the chip and use minimal heating.I did see a DIP desoldering tool that was a set of wide heated tongs so you can pinch all the legs at once, but they aren't going to be cheap.You can see some of the wide sets at the back, one for each side of some heated tweezers, but even the biggest looks to be for 28/32 pin DILs, some of the old processors could be far bigger.