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Surface Mount Component Removal

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cowboybob

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Thus far in my life I've soldered in place exactly 1 (one, uno) SM device (little IC in a kit QRP rig).

I have never removed one.

I want to remove the coupled inductor in the pic below (marked 752S) and replace it with another that has a different ratio (although is the exact same physical size). As you can see, it has four contacts.

View attachment 68314

Any hints out there on a method for removing the little sucker without destroying it, the components next to it or the board? The board is a multi-layer traces sort.

I have a binocular dissecting scope, so I will be able to see what I'm doing.

If need be, I guess destroying the inductor is an option.

Hints on re-soldering its replacement are also welcome.
 
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Thanks, John.

That looks like the ticket.

Can that also be used to "re-seat" the replacement component?
 
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I think both can be used to reseat, but be sure to add flux. Before switching to SMD, I had always used cored solder and didn't think much about additional flux. With SMD, you will find flux can be like an extra hand.

John
 
A normal temperature-controlled soldering iron and a dental pick. Put lots of solder on the iron tip, then touch it on two contacts at the same time, and with the dental pick under the component apply a SMALL amount of upward pressure. The component will tilt very slightly and you will get a fraction of a mm lift on that side.

Then repeat on the other side, lifting that side. Repeat both sides 5 or 6 times and it will be lifted 1-2mm. That is enough to get a solder sucker near it and suck out the solder in each pin in turn, so the component falls off.

It sounds complicated but the whole process only takes less than a minute and won't heat or cause issues with the other components.
 
Thanks, Mr RB.

Since I don't have the unit yet that John suggested, I might give your idea a shot. I've done thru-hole chips that way before but, like I say, just not SMs.
 
I have done as Mr RB suggests with SMD's that have identifiable pins (like SOIC, etc.). The four contacts on a rigid structure may present more of a challenge.

If you know anyone in a university chemistry or physics department, Woods metal or any very low melting alloy can be added to the solder to make a very low melting alloy that can be easily removed with a hair dryer. Chip-Quik is a commercial solder that is produced for that approach. The principle component in most such alloys is bismuth.

John
 
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