I decided to invest in a Hakko FR-301. It worked almost immediately. Hours of trying before, I did it in 10 minutes!
Regards Rob > -----Original Message----- > From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of dwight via cctalk > Sent: 16 April 2022 14:00 > To: General Discussion: On-Topic and Off-Topic Posts > <cctalk@classiccmp.org> > Subject: Re: Advice on Desoldering an IC > > Sometimes the IC has been installed with the pins under tension. This is > typical of machine inserted ICs. When the solder is loose, bend the pin away > from the side it is pressed against. Do this carefully, don't over bend. You > want it to center in the hole. I recommend doing this with a separate iron > than the desoldering tool, so you can see what you are doing. Once the pin is > nicely centered in the hole use the desoldering tool to suck the solder out. > Make sure to always use a clean tip. An oxidixed tip will require excess > pressure to transfer heatand damage the trace. Keep the solder shinny with > a spung or soft metal wool. Do mot use a hard metal to clean an iron clad tip > or it will damage the iron and rot it from the inside 🙁 > When not using the iron but leaving it hot, always leave a blob of solder so > that it won't have a thin oxide coating that is hard to remove. KEEP A CLEAN > TIP! > After sucking the solder with the tool, with a small screw driver, give the > pin a > slight sideways pressure and let the screw driver slip off the pin. It should > make a plink sound or a momentary ring. This is something that you'll just > have to learn the sound of. If it doesn't sound right it means it isn't free > of > the sides. Add solder and try to bend the pin. > Often the body side of the IC will have a tiny film of solder right where the > IC > sits on the trace. If this is just the tiny amount to solder, one can break it > loose with a pair of short needle nose pliers, By squeezing the two sides of > the IC together. Don't expect to break loose a large blob. > Of course, if you expect to throw the IC away, use sharp pointed dikes to cut > the pins at the package and pull each pin individually while the solder is > hot. > Use a small vice to hold the board so you can work from both sides. Tweezers > are best but heat the solder first and when hot grab the pin from the top. > Work quickly while the solder is hot. > You may need to refill the pin with fresh clean solder. Old oxidized solder > does not remove easily. Use separate rosin flux if you have it ( not plumber > flux!! ). > Like I said earlier, use a really clean tip. It should be shinny before > trying to > heat the board. It is hard to do with the higher temperature solders. There is > some low temperature stuff you can use to remove solder more quickly. > I like using a large manual plastic solderpulit. Some like to use solder wick. > The solder removal suckers are often hard to keep the tip clean. If you have > to press hard on the tip to the work, the tip is not clean. It does help to > have > some really tiny flux core solder to touch right at the junction of the iron > and > work to start the heat transfer. Never use force to get the heat to start to > transfer! Clean tip and a quick touch with solder is all that is needed. > When you are not using the iron for some time, but leaving it on, add a > thicker blob of solder on it so it doesn't get a thin hard to clean oxide on > it. > KEEP YOUR TIP FREE OF THIN OXIDE! > Dwight > > > > ________________________________ > From: cctalk <cctalk-boun...@classiccmp.org> on behalf of Rob Jarratt via > cctalk <cctalk@classiccmp.org> > Sent: Friday, April 15, 2022 10:49 AM > To: General Discussion: On-Topic and Off-Topic Posts > <cctalk@classiccmp.org> > Subject: Advice on Desoldering an IC > > I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really > struggling to desolder it. I am using the technique of applying fresh solder > and then removing it. But after multiple cycles of this I think I am starting > to > damage the PCB. > > > > I am using a fairly cheap desoldering station (this one > https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu- > plug/dp/SD > 01384?st=duratool%20desoldering). Its spec in terms of vacuum pressure is > equivalent to that of the professional Hakko ones though. I am also trying a > hand desoldering pump. None of these are able to clear many of the holes of > solder, although some are doing better than others. Nevertheless, the IC > remains stubbornly unmoving. > > > > Are there any tips for removing ICs? > > > > Thanks > > > > Rob
