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Ok, I have built almost a dozen of Hans's kits and this is the first time I put capacitors in the wrong spot. ?It is the new qmx+
I have removed the misplaced caps, but they are in bad shape. ?I used some flux and soldering wick to clean it up, but the hole
is full of solder. ?Any ideas how to fix this without ruining the board. ?And I will need some odd capacitors too. ?thanks. ?have a laugh on me.
At least is was at the beginning of the build.
72
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Bill, I just had an issue with what I thought was a misplaced cap on a kit I was building. ?After I removed the cap I heated up the solder on the board and slapped the board on my workbench….. out came a little bit of solder each time I did it. Eventually I was able to remove enough solder to reinsert the same cap…. I had made a mistake and THOUGHT I had put the wrong cap in the wrong place…. I misread the instructions and was correct the first time. Ha! ?Heat and slapping the board on a hard surface helps. Adding some more flux helps also. Be the REASON someone smiles today.
Dave K8WPE
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On Jul 8, 2024, at 6:50?AM, Bill VE3MRX <warubenstein@...> wrote:
?Ok, I have built almost a dozen of Hans's kits and this is the first time I put capacitors in the wrong spot. ?It is the new qmx+
I have removed the misplaced caps, but they are in bad shape. ?I used some flux and soldering wick to clean it up, but the hole
is full of solder. ?Any ideas how to fix this without ruining the board. ?And I will need some odd capacitors too. ?thanks. ?have a laugh on me.
At least is was at the beginning of the build.
72
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Bill
The ideal method to correct a misplaced component is often to sacrifice the component. You cut it apart and then simply heat the pad and pull out the half of the part. Makes it easy to clean out the hole and if done properly not only doesn't damage anything but can often leave the hole free and clear.
This part-sacrifice technique is for several reasons... the cost of the part is almost always a tiny fraction of the cost of the board, and especially so when other parts are already on the board! Also, the suddenly redundant lead of the part you cut off is more easily removed than the intact part is.
There are tools that can be used to remove the solder in the situation you describe without damaging the board. I'll assume you don't have any of these, given your comment, so then I have to ask if you know anyone else in your local area who does this sort of hobby work.
Wick can help BUT in a large percent of cases is rather risky. I'm not going to recommend wick for most people for most modern miniaturized use cases.
If you're a dedicated builder, you could just use this happenstance as a good excuse to acquire suitable tools 'for the next time' ... a handheld de-soldering pump is always at the ready on my bench, for example.
Interestingly while these devices are commonly found, there is an ENORMOUS difference between them. After fifty-plus years of building, the ONLY one that works ... and coincidentally is still available after decades **even after the appearance of surface mount technology** ... is the Edsyn DS-017 "Soldapullt."
I am unaffiliated with the company.
And yes, even though today I have a professional grade rework station with vacuum tool, I still use a Soldapullt ... and even have the original I bought when I was in high school in the 1970s.
73 Steve KZ1X
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Hi Bill, I think we've all been there in one way or another. Its better to destroy the component rather than the PCB in this case, so you'll have to buy a set of new caps.
I found a solution that works in this situation. Take the new capacitor and cut one of the leads so it is shorter than the other by about 5-6mm then apply heat to melt the solder in the desired blocked pad hole and once molten push the longer of the two cap leads through the hole until the shorter lead of the cap hits the component side of the board, then align this lead precisely with the other blocked pad hole (maybe put a bit of a bend in the longer lead to help here) and then heat both pads from the underside of the board using a soldering iron with a bit big enough to heat both pads at the same time slowly working the cap into place from the component side...a little rocking of the cap from side to side may help here.?
I appreciate the solder joints to the ground plane may need quite a bit of heat.
Hope this helps
73 Steve G4EDG
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You almost need three hands for this and I have the PCB braced up vertical since my board holder assembly jig doesn't have enough vertical clearance to work from underneath. This has worked fine for me.??
Use a hand resoldering sucker. Smaller, squared off plastic tip works best.?
Put some fresh solder on/in the hole. Then cock the solder sucker and place it on one side of the hole, firmly against the PCB.? Heat up from the opposite side and trigger the sucker.
If still not open, you can clear it by using a hand pin vise and very, very tiny drill bits. Start small, using the often clear depression outline of the via to start as close as you can to the center.? ?Go slow! Stop often and clear the curls of drilled out solder. Move up in drill sizes as needed BUT ...
DO NOT drill with a bit larger than a good clear hole of the same size!!!
Good luck?
GREG
On Mon, Jul 8, 2024 at 6:50 AM, Bill VE3MRX <warubenstein@...> wrote: Ok, I have built almost a dozen of Hans's kits and this is the first time I put capacitors in the wrong spot. ?It is the new qmx+
I have removed the misplaced caps, but they are in bad shape. ?I used some flux and soldering wick to clean it up, but the hole
is full of solder. ?Any ideas how to fix this without ruining the board. ?And I will need some odd capacitors too. ?thanks. ?have a laugh on me.
At least is was at the beginning of the build.
72
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This works pretty good for the price.
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73, Barb, WB2CBA
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Hi Bill. The easiest method I’ve found which has not yet been mentioned is to simply snip off the old cap and solder the new one directly to the pads on the top (or bottom if necessary) of the board. No board damage. No clean up.? Good solid connection every time. The plated-thru hole makes the connection top to bottom if you already removed the part and the little piece of soldered remaining lead makes the connection as well if you just snip the part off. Since the part is usually destroyed anyway this method is the safest for the board and easiest to accomplish and just as good electrically and mechanically in my opinion.?
73…搁辞苍
This works pretty good for the price.
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73, Barb, WB2CBA
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As stated by someone else, I have always had good success holding vertically, heating from one side then placing a solder sucker over the hole squarely and just sucking the solder out of the hole. Careful you don't suck the soldering iron tip into the hole, I have damage a pad with a smaller tip getting stuck in the hole and lifting a pad when removed heh, best to use the soldering iron a bit leaned over /use a bigger tip then the hole.
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I've been successful with a low pressure compressed air gun under the board.? When the solder flows,? give it a short blast of air.? Be careful to only heat the pad you're trying to clear.? ?If you have a piece of surgical or silicone tube,? you could do the same thing by blowing through it.? WEAR YOUR SAFETY SPECS.
Eric?
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For clearing stubborn through holes with the leads already removed, I set the board up in a set of helping hands so I can reach both sides, add a little flux, heat the pad on one side until the solder flows, then push a toothpick through the hole while simultaneously removing the iron. Leave the toothpick in the hole while cleaning up remaining solder around it if needed to keep capillary action / surface tension from closing it back up.
This lets me consistently clear the holes without subjecting the board to many heating cycles. This might help for your situation as well.
Good luck!
Greg, K1UGP
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These gadgets tend to overheat causing damage to pads. So it is advised to control heating by using? electronic fan regulator in series.
Now the pads are safe from excessive heat and knocking/hammering due to sudden release of plunger in the desoldering gadget.
This fan regulator tricks also helps other soldering irons from overheating & damaging their bits. Overheating causes the bit & solder to corrode/oxidise quickly. Adjust the regulator so the tip of the bit stays shiny with clear molten solder.?
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Sir, you can use any small vice to hold the PCB vertically, I have used a grip plier instead with satisfactory results. Just make sure the grip plier or vice jaws are holding only the bare PCB edges tightly, there should not be any components in there.
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+1 for the toothpick method.
Bruce K1FFX?
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Thanks so much for all the advice, I am not the first one faced with this problem. ? A local ham with a big history of radio repair suggested drilling out the hole with a #60 drill bit. ?But as a retired oral surgeon, I still have a handpiece that is used for dental implants. ?It is very solid and has lots of torque. ?There is a dental burr called a half round. ?I dont remember what it is half of, but it is probably about 1/2 mm. ?I used it to drill out the holes and here is how it looked.
I salvaged 2 of the caps that I removed and replaced one with a duplicate I had in my junk box. ?I am hoping I did not screw up any of the layers of the board, but time will tell.
tnx agn all. de ve3mrx Bill 72
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On Tuesday, 9 July 2024 10:39:40 -04 Bill VE3MRX via groups.io wrote: Thanks so much for all the advice, I am not the first one faced with
this problem. A local ham with a big history of radio repair
suggested drilling out the hole with a #60 drill bit. But as a
retired oral surgeon, I still have a handpiece that is used for
dental implants. It is very solid and has lots of torque. There is
a dental burr called a half round. I dont remember what it is half
of, but it is probably about 1/2 mm. I used it to drill out the
holes and here is how it looked.
I salvaged 2 of the caps that I removed and replaced one with a
duplicate I had in my junk box. I am hoping I did not screw up any
of the layers of the board, but time will tell.
tnx agn all. de ve3mrx Bill 72
Dear Bill, drilling is *very* risky which you already realized according to your remark that you hope that you did not damage any of the layers. The low-tech toothpick method is far safer. vy 73 de Eike KY4PZ / ZP5CGE
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On Tue, Jul 9, 2024 at 11:03 AM, Eike Lantzsch wrote:
The low-tech toothpick method is far safer.
A suitably-sized sewing needle works well also and will not damage the board.? The via "barrels" which connect the board layers are very thin and fragile electroplated copper so I keep drills and abrasives away from them. One tactic to deal with a hole which has had most of the solder removed but there is a stubborn residue, is to add MORE solder to fill the hole, and start over. 73, Don N2VGU
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I recommend a desoldering gun with built-in vacuum pump, adjustable temperature control, and replaceable tips of various diameters, such as the Hakko FR-301.? Several other manufacturers offer similar products.? I have a hand tremor that makes it very difficult to hold a soldering iron, especially when components are spaced close together.?? I had just about given up assembling kits because I spent so much time fixing my own mistakes.? Then a friend told me about his Hakko and I found out that once a year the factory has a 50% off sale, and it just happened to be the next day.? I figured I could try it, and if it didn't work out, I should be able to recoup most of my money on eBay, so I bought one.? It's so nice that I kept it.? Highly recommend it!
On Tue, Jul 9, 2024, 11:26 Donald S Brant Jr via <dsbrantjr= [email protected]> wrote: On Tue, Jul 9, 2024 at 11:03 AM, Eike Lantzsch wrote:
The low-tech toothpick method is far safer.
A suitably-sized sewing needle works well also and will not damage the board.?
The via "barrels" which connect the board layers are very thin and fragile electroplated copper so I keep drills and abrasives away from them.
One tactic to deal with a hole which has had most of the solder removed but there is a stubborn residue, is to add MORE solder to fill the hole, and start over.
73, Don N2VGU
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Bill,
I have had some criticism for drilling out the left over solder in a through hole opening but I have done it for years (not too many times though). I am just an old Osteopathic family doctor but have used a finger drill and the very fine bits with success. ?I was warned about drilling out the through hole plating but just added a little solder on both sides of the board. ?The few times I had to do that it did work…. So go drill! ?I would like to see what a “half” bit looks like…. Have had one root canal done but wasn't interested in the tools that day. Ha! Be the REASON someone smiles today.
Dave K8WPE
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On Jul 9, 2024, at 10:39?AM, Bill VE3MRX <warubenstein@...> wrote:
?Thanks so much for all the advice, I am not the first one faced with this problem. ? A local ham with a big history of radio repair suggested drilling out the hole with a #60 drill bit. ?But as a retired oral surgeon, I still have a handpiece that is used for dental implants. ?It is very solid and has lots of torque. ?There is a dental burr called a half round. ?I dont remember what it is half of, but it is probably about 1/2 mm. ?I used it to drill out the holes and here is how it looked. I salvaged 2 of the caps that I removed and replaced one with a duplicate I had in my junk box. ?I am hoping I did not screw up any of the layers of the board, but time will tell. tnx agn all. de ve3mrx Bill 72
<image1.jpeg>
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Great suggestion Hakka makes great products.
I recommend a desoldering gun with built-in vacuum pump, adjustable temperature control, and replaceable tips of various diameters, such as the Hakko FR-301.? Several other manufacturers offer similar products.? I have a hand tremor that makes it very difficult to hold a soldering iron, especially when components are spaced close together.?? I had just about given up assembling kits because I spent so much time fixing my own mistakes.? Then a friend told me about his Hakko and I found out that once a year the factory has a 50% off sale, and it just happened to be the next day.? I figured I could try it, and if it didn't work out, I should be able to recoup most of my money on eBay, so I bought one.? It's so nice that I kept it.? Highly recommend it!
On Tue, Jul 9, 2024, 11:26 Donald S Brant Jr via <dsbrantjr= [email protected]> wrote: On Tue, Jul 9, 2024 at 11:03 AM, Eike Lantzsch wrote:
The low-tech toothpick method is far safer.
A suitably-sized sewing needle works well also and will not damage the board.?
The via "barrels" which connect the board layers are very thin and fragile electroplated copper so I keep drills and abrasives away from them.
One tactic to deal with a hole which has had most of the solder removed but there is a stubborn residue, is to add MORE solder to fill the hole, and start over.
73, Don N2VGU
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My only concern about using a drill is with multi-layer circuit boards, it might be possible to disconnect the through hole connections.
Dean - KC9REN
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On Wed, Jul 10, 2024 at 06:18 AM, David Wilcox K8WPE wrote:
Bill,
?
I have had some criticism for drilling out the left over solder in a through hole opening but I have done it for years (not too many times though). I am just an old Osteopathic family doctor but have used a finger drill and the very fine bits with success. ?I was warned about drilling out the through hole plating but just added a little solder on both sides of the board. ?The few times I had to do that it did work…. So go drill! ?I would like to see what a “half” bit looks like…. Have had one root canal done but wasn't interested in the tools that day. Ha!
Be the REASON someone smiles today.
?
Dave K8WPE
?
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Bill VE3MRX
David Wilcox K8WPE
Steve G4EDG
Barb WB2CBA
Ronald Taylor
Eric K7EBR
Donald S Brant Jr