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Desoldering ICs

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
38,867
Location
Pacific Northwest, USA
Better to just clean the board well. Solder doesn't stick to oxidized/corroded copper.

Plumber's flux is mostly ammonium chloride which, when heated tends to get everywhere you don't want it to be, leading to corrosion in unexpected places.
 

vldmrrr

Experienced Member
Joined
Aug 20, 2016
Messages
131
Location
IA, USA
Copper pipe desoldering tool

Copper pipe desoldering tool

Here is a homemade tool that I've used for removing through hole DIP parts up to 40 pins.

I've cut a piece of 3/4" copper pipe to the length of the part to be de-soldered. Then I cut the pipe lengthwise with hack saw. For wider parts I made a second cut removing a segment of copper, but depending on density of board, the pipe with a single cut probably can be just bent to create sufficient opening. Then I heat the pipe with butane torch and covered the edge with solder. Here is a picture of three different sizes.

pipes.jpg

The tool works by fitting it tight over pins and heating the top with small butane torch. The heat is transferred to the pins melting solder around them. At that stage the part can be lifted with flat forceps, for longer part lift one side first, move the forceps deeper under the part and lift the whole. After lifting I quickly remove the pipe from the part. Here is a staged photo of two pipes fitted over the board - for illustration, not a real rework.

board.jpg

I used these on several occasions, not too often yet to develop a good skill, so I am still quite nervous during operation, but results were all good thus far. For example, I removed Z80 CPU and few other similar sized chips, and I later re-installed them on sockets into the same board, and it worked well. On couple of boards I removed a complete set of DRAM chips to find bad ones and returned good ones back into newly installed sockets. Never damaged a single trace yet.
 
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Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
38,867
Location
Pacific Northwest, USA
There used to be U-channel shaped adapters for irons that did a similar thing.

How do you clear the holes in the PCB after the IC's been removed?
 

Agent Orange

Veteran Member
Joined
Sep 24, 2008
Messages
6,069
Location
SE MI
There used to be U-channel shaped adapters for irons that did a similar thing.

How do you clear the holes in the PCB after the IC's been removed?

Once up on a time I used to use a Dremel with a very very fine bit. Not kosher for some, but worked fine for me in some instances. My Pace station was known wreak havoc on cheaper PCB's eyelets even while attempting to be very careful.
 

vldmrrr

Experienced Member
Joined
Aug 20, 2016
Messages
131
Location
IA, USA
How do you clear the holes in the PCB after the IC's been removed?

I just use a round wooden toothpick that I sharpen a bit with razor blade. With that I poke holes from component side melting solder with regular solder iron from opposite side (board mounted vertically). Then I cut off some of excessive solder on the opposite side with fine flat clippers. This make the site ready for replacement in a short time.

I usually put a socket with round gold-plated connectors instead of soldering replacement chip directly. Having sockets facilitates troubleshooting and later, when the board is working, it can be used for testing other questionable chips of the same kind.
 

VERAULT

Veteran Member
Joined
Jan 30, 2012
Messages
5,079
Location
Connecticut, USA
You get both of those with hardwood as well. You can burn pine, just make sure its bone dry.

And sure why not, I was picking my moment..
 
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