OT: Removing Solder Through Plated Through Holes
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OT: Removing Solder Through Plated Through Holes
 
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Re: OT: Removing Solder Through Plated Through Holes
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Lee,
Good that you have finished the task without damaging the board. If something like that happens again, remember that after the solder wick, you can open the hole with a toothpick, or even better a stainless steel needle. In a pinch, a sewing needle will do the job nicely, but stick the eye end into a cork to keep from burning your fingers - the needle will get hot in the process. With plated-thru holes, the "name of the game" is to protect the board - using a drill will remove the thru-plating from the hole - so don't do that. 73, Don W3FPR Lee Buller wrote: > > Hey, > > Lots of good ideas here. I did use the solder wick. That was a no > brainer, but getting all the solder out of the holes is a different > deal. I rummaged around in my tool drawer and I found a "solder > sucker" which was spring loaded. I got it years ago from Radio Shack. > I never had any luck with it...but in this application seemed to work > well. I got the holes cleaned up....now...I can start again. But > alas...I think I need to get some more resistors too...I broke one. > > Thanks for the ideas guys. > > Lee - K0WA > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by k0wa@swbell.net
Lee, glad you got it sorted.
Just a note - don't ever use a drill on through-plated holes - you will probably remove the 'plating' and disconnect the 2 sides - not so much a problem if it's just a double-sided board, you can solder each side (unless one side has a protective coat). But on multi-layer boards, you're bound to break the connection. 73 de M0XDF, K3 #174 -- It is forbidden to kill; therefore all murderers are punished unless they kill in large numbers and to the sound of trumpets. -Voltaire, philosopher (1694-1778) On 30 Dec 2008, at 03:24, Lee Buller wrote:
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Re: OT: Removing Solder Through Plated Through Holes
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In reply to this post by Don Wilhelm-4
YEARS AGO... Prior to changing out the "unmatched" crystals for
"matched" ones in my K2, I decided that it was time to buy that "solder sucker ... The HAKKO 808... the handheld powered vacuum sucker... I was concerned about the number of desolderings involved on the main board. AND IT was a GREAT idea. When it came time to do the audio mod,,, just sucked that solder out from the bottom and miraculously... the part fell out . Great to have around for all those projects repair and building ,,, esp when you make a mistake or two,, bill _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: OT: Removing Solder Through Plated Through Holes
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In reply to this post by k0wa@swbell.net
If I have done what you say I shouldn't , meaning take a hobbyist drill to widen a solder-filled hole, how do I check if I have broken the connection between top side and bottom side? Thanks for help,
Jim Curione KC2ROF _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Well, if the board is clean and free of components, then you should be able to measure resistance 9or lack of it) between the pads on either side.
For double sided boards, this may not be a big problem, just make sure you solder whatever lead is going through the hole on both sides. 73 de M0XDF, K3 #174 -- Ok, so what's the speed of Dark? On 30 Dec 2008, at 22:17, [hidden email] wrote:
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Re: Re: OT: Removing Solder Through Plated Through Holes
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In reply to this post by Jim Curione
Jim,
You look at the schematic and find *all* the paths connected to that component location - then you check for continuity from the potentially damaged pad to all the other locations. Even if you don't know how to "read" a schematic sufficiently to identify the circuit function, it can still tell you 'which is supposed to be connected to what', and that is what you must check. With 2 sided boards, sometimes you can tell by looking at the board and see the traces coming from the potentially damaged hole - if the circuit is not complex, all the wiring may be all on one side and all you need to do is to be certain to solder that side containing the PC board traces. Normally on 2 sided boards, an effective repair is to solder the component lead both on the top and the bottom. If you are dealing with a multilayer board - the process of using the schematic is the same, but the process is more complex since there can be a path from each layer. To repair in this situation, one would run discrete wire point to point for the entire network containing that hole (it is the only certain thing to do other than replacing the board). Bottom line (may be 20-20 hindsight) - use a drill *only* on single sided boards or boards that are known to *not* have thru-plated holes. Many holes are used as a continuation of the circuit from one side of the board to the other (known as "via holes" and those holes can serve double duty as a mounting place for a component lead. All such damages are repairable with the possible exception of carefully laid out VHF/UHF circuits - even if the repair is a PITA. 73, Don W3FPR [hidden email] wrote: > > If I have done what you say I shouldn't , meaning take a hobbyist > drill to widen a solder-filled hole, how do I check if I have broken > the connection between top side and bottom side? > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Re: Re: OT: Removing Solder Through Plated Through Holes
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Mel,
Despite all the exotic methods, one thing is true - solder suckers of all types work much better when there is a lead in the hole to be de-soldered (the lead conducts heat through the hole). Clearing the hole after the lead is removed is a different matter entirely. For my part sticking something that solder will not adhere to into the hole (after heating the solder pad with a soldering iron) is quite effective. A wooden toothpick will work, but I use a stainless steel needle. I have several with handles than I have picked up at hamfests, but in a pinch a sewing needle with the eye end embedded into a cork works fine too (the needle will get hot, and the cork is only 'finger protection'). 73, Don W3FPR Mel Farrer wrote: > I would like to add a comment on removing solder from SMT via holes. > There are three methods and the first two have been discussed. I have > found as the technology gets better, smaller, the plated through holes > also get really small. Like 0.020 or smaller. Solder suckers have a > very difficult time pulling the solder up. > > Let me explain, consider the mass of the solder pad on the side you > are going to apply heat. If you get the solder liquid and don't > destroy the pad, the bottom pad, MAY be liquid and come up with the > sucker type. It works good on larger pads but not so good as the > holes get smaller. Too much air leakage and you are trying to pull > cold solder. Not always successful. > > Using the solder braid has also the same problem as it is a heat sink > and usually requires you to put additional heat to suck the solder > up. Works great on larger holes and traces that are large like 50 ohm > strip line. > > OK, so what is left? I use a solder "pusher". Back before someone > invented the solder sucker, we used a small hollow rubber ball with a > small entrance teflon tube that we had and it had replaceable tips of > different sizes to accommodate hole size. This allows exact pressure > of the right size on the hot side of the PCB and "blows" hot solder > out against the colder solder on the other side and effectively cleans > the hole without over heating the pad......... > > From someone who is long in the tooth, > > Mel K6KBE > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Mel
At 07:53 PM 12/30/2008, Mel Farrer wrote...
>I would like to add a comment on removing solder from SMT via >holes. There are three methods and the first two have been >discussed. I have found as the technology gets better, smaller, the >plated through holes also get really small. Like 0.020 or >smaller. Solder suckers have a very difficult time pulling the solder >up. There is no need to remove solder from SMT via holes. It's only necessary for the holes used by through-hole components. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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