Advice on Desoldering an IC

[W2HX]

Indeed! Great investment. 


73 Eugene W2HX
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-----Original Message-----
From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Rob Jarratt via cctalk
Sent: Friday, April 22, 2022 2:04 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' <cctalk at classiccmp.org>
Subject: RE: Advice on Desoldering an IC

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-bounces at classiccmp.org> On Behalf Of dwight via 
> cctalk
> Sent: 16 April 2022 14:00
> To: General Discussion: On-Topic and Off-Topic Posts 
> <cctalk at 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-bounces at classiccmp.org> on behalf of Rob Jarratt 
> via cctalk <cctalk at classiccmp.org>
> Sent: Friday, April 15, 2022 10:49 AM
> To: General Discussion: On-Topic and Off-Topic Posts 
> <cctalk at 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