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joshc

Trouble removing solder from through hole component

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I am recapping one of my SE/30s and I am having lots of trouble removing solder from one of the through holes for one of the axial caps. I've done 3 of the holes fine (4 in total, 2 each for 2 caps), but the last one just wants to be difficult - there is a really small piece of the old capacitor lead stuck in-between the board, and heating the solder from either side and trying to push it through is not working. Using desoldering wick and tons of flux is also not working, perhaps my desoldering wick is a bit too chunky for this size hole to pick up all the solder? I tried a smaller solder tip and tried pushing it through the hole, again no good. I also tried with a hot air gun but again still couldnt get it to push through. I've tried using tweezers while the joint is heated to pull or poke through - again not happening.

 

Any finally, I tried my solder sucker after adding new solder hoping it would just suck it all up, but alas it sucks it up to the point I've got in the photos below...

 

I am at the point where I think my only option is to drill it out, however I don't have a small enough drill bit for this so I would have to buy one...

 

See photos attached to see what I'm dealing with...any ideas?

 

IMG_8985.thumb.jpg.ced126dce4be10b1ff7f463dab66c857.jpg

 

IMG_8983.thumb.jpg.b45e270629fc45510c8e49ded4255a05.jpg

 

 

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I use chipquik for these types of issues. It’s a low melt point alloy that’s used to easily remove smd components. I find it also works great for these types of through hole components where they terminate to a big ground plane that sucks out the heat right away. 

 

You mix the chipquik solder into the solder in the hole (maybe on both sides) and it comes out super easy.

 

Alternatively a bigger solder tip that carries more heat will work but the chip quik carries less risk of damage. 

 

Please don’t drill it!! 

Edited by superjer2000

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Use hot air to preheat the area around the joint, then try the solder sucker again. Even irons with a lot of ooomph will have problems melting those kind of joints that connect to huge ground planes without any form of preheating.

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Just to clarify, I am already using a large chisel edge tip.

 

I will try the suggestion of preheating with hot air and then solder sucker again.

 

Thanks both.

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Usually the way I tackle this: somehow prop the board up on its side (securely). Then, heat one side with your regular iron. VERY CAREFULLY - heat the other side with the sucker for a few seconds then suck it out. The heat from both  usually will do it.

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Two suggestions from my experience.

Whenever you have trouble melting solder or need it to flow well, mix in some fresh solder, it will allow for the use of less heat to melt the solder.

I also have a specialty tool for clearing out stubborn board through holes.  A sewing needle held in a pair of needle holder forceps.

(stick the needle in the hole, holding it locked in the forceps, and then touch the soldering tip to the needle, which will conduct the heat through the needle and into the hole, removing the obstruction)

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I second the suggestion of adding more solder. Don’t be afraid to pile it on, just make sure it actually transfers enough heat to what’s there that the whole mess melts. The additional thermal inertia and area will give the solder sucker a better chance.

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10 hours ago, Juror22 said:

A sewing needle held in a pair of needle holder forceps

That's a good trick.  I'm keeping that one.  Thankyou :-)

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If all else fails, I’ve used tiny drill bits in a pin vise manually drilling out the solder in the middle. You have to be careful, but it works.

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I am also a fan of the needle (or pin) method.    I usually pile on the flux and heat the hole from one side and poke the needle through from the other side.  The solder typically does not stick to the needle, so it can be withdrawn afterwards leaving a hole.

 

Also, to amplify/clarify Bolle's advice, your soldering iron may simply lack the **power** to melt the solder if the heat is being drawn off by the circuit board ground plane or some such.    In those cases, hot air or a more powerful pencil may be needed.  Doesn't matter what tip you use if your pencil can't deliver enough power to overcome the heat being radiated away across a large plane of copper.

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Not that these other methods aren't great, but I would still seriously recommend looking into ChipQuik.  This stuff is seriously awesome and saves a ton of time.  In situations like this I can have the offending component leg removed in about 15 seconds with zero change of damage.

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7 minutes ago, superjer2000 said:

Not that these other methods aren't great, but I would still seriously recommend looking into ChipQuik.  This stuff is seriously awesome and saves a ton of time.  In situations like this I can have the offending component leg removed in about 15 seconds with zero change of damage.

What's the specific ChipQuik product that you use?

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8 hours ago, superjer2000 said:

Not that these other methods aren't great, but I would still seriously recommend looking into ChipQuik.  This stuff is seriously awesome and saves a ton of time.  In situations like this I can have the offending component leg removed in about 15 seconds with zero change of damage.

 

I should mention that I have also used ChipQuik and it is great stuff.    I've found that with skill and lots of flux, I can usually manage without it, but it can be very useful.

 

It will also allow you to non-destructively remove large surface mount chips without hot air.   Get beads of ChipQuik across all the pins of your SM chip and the melting point is low enough, that you can get the whole beads hot enough with a pencil to lift off the SM chip.   Cleaning up all the ChipQuik afterwards is a small chore.    Must use beads down the whole row, so that you can heat all the pins per row at the same time, rather than one pin at a time.

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What I usually do - I mix with fresh solder and wick it up, if its stubborn enough then I will drill it out as I do have a small hand held drill - see pic;

Cheers
AP

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You can heat it up with a soldering iron or hot air workstation and use a large sewing needle to push the solder out, or you can use a circuit board drill bit and remove it.

 

https://www.ebay.com/itm/10x-Alloy-PCB-Print-Circuit-Board-Carbide-Drill-Bits-Color-Radomly-0-3-1-2mm/372683271091

 

You can actually drill out the soft solder with one of those bits just using your fingers holding the bit on the plastic part and twist. They are kind of brittle so they break easy, but cheap to replace.

 

 

Edited by Unknown_K

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Hello guys,

yes I also have used the needle idea and does work well I am going to order from mouser some chip quick just making a list for caps for my MAC SE/30 that am going to restore 

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Hello joshc,,

what soldering iron are you using myself I have Weller soldering station and it gets nice and hot anyway that's cool that you are also rebuilding a Se/30 too they are like the best machine far as the B/W CRT ones go 

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The desoldering station worked perfectly, it just sucks the solder away immediately - wish I had bought one sooner!!

 

On 5/17/2020 at 12:39 AM, radiorich said:

Hello joshc,,

what soldering iron are you using myself I have Weller soldering station and it gets nice and hot anyway that's cool that you are also rebuilding a Se/30 too they are like the best machine far as the B/W CRT ones go 

 

I use this soldering station: http://yihua-soldering.com/product-1-3-2-hot-air-rework-station-en/147663/

 

You can see my SE/30 rebuild thread here, although the logic board I was working on in this thread is actually from a different SE/30, but this is the one that I have mostly finished:

 

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