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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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general question: mainboard caps
Hello,
I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) Is desoldering these caps straightforward? Any special precautions multi-layered PCB traces? Any special gotchas to keep in mind when ordering replacement caps from say Mouser? Thanks, Michael |
#2
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general question: mainboard caps
On 9/20/2010 2:52 PM, Michael wrote:
Hello, I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) Is desoldering these caps straightforward? Any special precautions multi-layered PCB traces? Any special gotchas to keep in mind when ordering replacement caps from say Mouser? I fully recapped a pair of Dell Optoplex GX-280 mother boards. About 15 or so caps per board. Using a vacuum desoldering tool is the best method, but you can remove the caps but using a wide enough tip to hit both leads at the same time, then go back and clean the solder out of the holes with a piece of stainless steel like a dental pick. Melt, stuff, let cool and remove. On the caps look for "low esr" and 105C temperature range. I try to buy Nichicon caps by default. At $1 or so apiece, it's not worth saving a few cents to get a crap cap that won't last. Jeff |
#3
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general question: mainboard caps
Jeffrey Angus wrote in message
... On 9/20/2010 2:52 PM, Michael wrote: Hello, I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) Is desoldering these caps straightforward? Any special precautions multi-layered PCB traces? Any special gotchas to keep in mind when ordering replacement caps from say Mouser? I fully recapped a pair of Dell Optoplex GX-280 mother boards. About 15 or so caps per board. Using a vacuum desoldering tool is the best method, but you can remove the caps but using a wide enough tip to hit both leads at the same time, then go back and clean the solder out of the holes with a piece of stainless steel like a dental pick. Melt, stuff, let cool and remove. On the caps look for "low esr" and 105C temperature range. I try to buy Nichicon caps by default. At $1 or so apiece, it's not worth saving a few cents to get a crap cap that won't last. Jeff If you can clamp to the cap and pull at the same time it helps, I use a surgical instrument like arterial forceps but longer opening arms and full gripping teeth (retraction clamp?). For the cleaning out of holes I made up a set of needle probes from different sized st/st sewing needles glued into ballpoint pen barrels or into drilled dowel |
#4
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general question: mainboard caps
No 16 of part of my tool kit is the specific clamp
http://www.diversed.fsnet.co.uk/tools_s.jpg if anyone should happen to know the medical name for. Number 17 are surgical terminology "Spencer Wells" , good for heatsinking etc |
#5
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general question: mainboard caps
goggling , probably Baby-Allis forceps
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#6
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general question: mainboard caps
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael
wrote: I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) My experience is that if you have the usual 8-10 identical capacitors on the motherboard, and one is visibly defective, then the others are highly likely to fail very soon. I replace *ALL* the caps of a specific type. In particular, the caps around the CPU tend to die, because of the heat and the high ripple current. Typically, I'll replace 10 to 15 caps. Is desoldering these caps straightforward? It varies. Some boards are very easy to unsolder. Others have smaller holes for the leaded parts and are more difficult. A vacuum desoldering station is best. Use plenty of heat and some liquid flux so that you don't pull the plated thru hole out with the capacitor. If you see a copper colored ring around a capacitor lead, you've probably killed the board. Any special precautions multi-layered PCB traces? If you don't have a tip that will heat both leads at the same time, or don't have 3 arms so that you can use two soldering irons, all is not lost. I heat up one lead, and rock the capacitor in the opposite direction. After it moves a little, I heat the other lead, and rock it in the opposite direction. Don't use brute force or you'll rip out the plated through holes. Eventually, it comes out. One lead is usually grounded where the large copper area acts as an effective heat sink. This lead will be more difficult to unsolder than the hot lead (usually +). I use a big, wide (1/4"), hot (850C), chisel tip. Plenty of heat, and work fast. This will take some practice. Find an old PCB and practice a little before attacking the Intel motherboard. Any special gotchas to keep in mind when ordering replacement caps from say Mouser? 105C Low-ESR. Watch the case dimensions and lead spacing. If it will fit, try to buy the next higher voltage rating. I'm partial to Panasonic but will use Rubycon. Digikey, Mouser, and eBay (in that order). I sometimes use polymer caps as replacements, when the motherboard is worth fixing and the customer doesn't care about the cost. Also, think about buying an ESR tester if you're going to make a habit of this. http://www.badcaps.net http://www.afrotechmods.com/groovy/capacitor_replacement/capacitor_replacement.htm http://en.wikipedia.org/wiki/Capacitor_plague http://www.capacitorlab.com -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#7
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general question: mainboard caps
On Sep 21, 9:44*am, Jeff Liebermann wrote:
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael wrote: I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. *One board stopped working; the other still works, but has a bulging cap close to the CPU area. *(Pics not yet available.) My experience is that if you have the usual 8-10 identical capacitors on the motherboard, and one is visibly defective, then the others are highly likely to fail very soon. *I replace *ALL* the caps of a specific type. *In particular, the caps around the CPU tend to die, because of the heat and the high ripple current. *Typically, I'll replace 10 to 15 caps. Is desoldering these caps straightforward? It varies. *Some boards are very easy to unsolder. *Others have smaller holes for the leaded parts and are more difficult. *A vacuum desoldering station is best. *Use plenty of heat and some liquid flux so that you don't pull the plated thru hole out with the capacitor. If you see a copper colored ring around a capacitor lead, you've probably killed the board. Any special precautions multi-layered PCB traces? If you don't have a tip that will heat both leads at the same time, or don't have 3 arms so that you can use two soldering irons, all is not lost. *I heat up one lead, and rock the capacitor in the opposite direction. *After it moves a little, I heat the other lead, and rock it in the opposite direction. *Don't use brute force or you'll rip out the plated through holes. *Eventually, it comes out. * One lead is usually grounded where the large copper area acts as an effective heat sink. *This lead will be more difficult to unsolder than the hot lead (usually +). *I use a big, wide (1/4"), hot (850C), chisel tip. *Plenty of heat, and work fast. *This will take some practice. *Find an old PCB and practice a little before attacking the Intel motherboard. Any special gotchas to keep in mind when ordering replacement caps from say Mouser? 105C Low-ESR. *Watch the case dimensions and lead spacing. *If it will fit, try to buy the next higher voltage rating. *I'm partial to Panasonic but will use Rubycon. *Digikey, Mouser, and eBay (in that order). *I sometimes use polymer caps as replacements, when the motherboard is worth fixing and the customer doesn't care about the cost. *Also, think about buying an ESR tester if you're going to make a habit of this. http://www.badcaps.net http://www.afrotechmods.com/groovy/capacitor_replacement/capacitor_re... http://en.wikipedia.org/wiki/Capacitor_plague http://www.capacitorlab.com -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558 Ok, thanks to everyone who replied. Seems doable... looks like I'm going shopping for a vacuum desolderer. Michael |
#8
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general question: mainboard caps
On Sep 21, 11:28*am, Michael wrote:
Ok, thanks to everyone who replied. *Seems doable... looks like I'm going shopping for a vacuum desolderer. For a one-off project, desoldering braid (it sucks up solder like a sponge) is almost as good, and doesn't have the sticker-shock effect. Practice on a scrap board or two FIRST. It's easy to damage things while the iron is hot and the polymers are soft. |
#9
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general question: mainboard caps
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael
wrote: Hello, I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) Is desoldering these caps straightforward? Any special precautions multi-layered PCB traces? Any special gotchas to keep in mind when ordering replacement caps from say Mouser? Thanks, Michael I've done this on motherboards; it's tedious, but practical. The suggestions from others are good. Here's a few things I discovered. While vacuum desoldering tools work well, you have to heat the board to the point where the solder on the ground lead melts all the way through the board. The vacuum desoldering tools aren't real efficient at transfereing heat unless you add a little solder or flux to each lead you are going to unsolder. The technique I settled on was to use a 40 watt soldering iron with a chisel tip. Heat up one leg, add a dab of Chip-Quik, rock the cap toward the opposite side. Heat up the other leg, add Chip-Quik, rock cap to other side. Repeat with the heating and rocking until the cap drops out. While it's still hot, push an iron or stanless steel needle through the hole (I use a dissecting pick I got in the '60's). Remove the pick when the solder has cooled; reheat the other hole and use the needle. Make sure you keep a chart identifying which cap goes where. Patience is necessary. Make sure you clean up all stray solder. PlainBill |
#10
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general question: mainboard caps
wrote in message ... On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael wrote: Hello, I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. One board stopped working; the other still works, but has a bulging cap close to the CPU area. (Pics not yet available.) Is desoldering these caps straightforward? Any special precautions multi-layered PCB traces? Any special gotchas to keep in mind when ordering replacement caps from say Mouser? Thanks, Michael I've done this on motherboards; it's tedious, but practical. The suggestions from others are good. Here's a few things I discovered. While vacuum desoldering tools work well, you have to heat the board to the point where the solder on the ground lead melts all the way through the board. The vacuum desoldering tools aren't real efficient at transfereing heat unless you add a little solder or flux to each lead you are going to unsolder. The technique I settled on was to use a 40 watt soldering iron with a chisel tip. Heat up one leg, add a dab of Chip-Quik, rock the cap toward the opposite side. Heat up the other leg, add Chip-Quik, rock cap to other side. Repeat with the heating and rocking until the cap drops out. While it's still hot, push an iron or stanless steel needle through the hole (I use a dissecting pick I got in the '60's). Remove the pick when the solder has cooled; reheat the other hole and use the needle. Make sure you keep a chart identifying which cap goes where. Patience is necessary. Make sure you clean up all stray solder. PlainBill Good advise and also make sure you take note of the polarity. |
#11
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general question: mainboard caps
On Tue, 21 Sep 2010 11:28:35 -0700 (PDT), Michael
wrote: Ok, thanks to everyone who replied. Seems doable... looks like I'm going shopping for a vacuum desolderer. While a proper vacuum desoldering station is nice, you can get away with using a solder sucker. http://www.amazon.com/SOLDER-SUCKER-DESOLDERING-DESOLDER-REMOVAL/dp/B0002Y8OPM It requires some practice at both using and cleaning. I use one when I'm too lazy to fire up the desoldering station. Someone suggested using solder braid. I disagree. I've lifted so many traces and pads from the board with solder braid, that I won't use it unless I'm depserate. Don't forget the stainless steel needle or pin for cleaning the hole. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com # http://www.LearnByDestroying.com AE6KS |
#12
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general question: mainboard caps
On 9/21/2010 8:51 PM, Jeff Liebermann wrote:
Someone suggested using solder braid. I disagree. I've lifted so many traces and pads from the board with solder braid, that I won't use it unless I'm desperate. About the only thing solder braid is good for is phenolic PC boards with brass rivets for the through holes. That and lifting traces. Jeff (the other other one) |
#13
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general question: mainboard caps
Jeffrey Angus wrote: On 9/21/2010 8:51 PM, Jeff Liebermann wrote: Someone suggested using solder braid. I disagree. I've lifted so many traces and pads from the board with solder braid, that I won't use it unless I'm desperate. About the only thing solder braid is good for is phenolic PC boards with brass rivets for the through holes. That and lifting traces. And cleaning the solder off the pins of Octal tubes. -- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them. |
#14
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general question: mainboard caps
On Sep 21, 4:59*pm, "tm" wrote:
wrote in message ... On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael wrote: Hello, I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. *One board stopped working; the other still works, but has a bulging cap close to the CPU area. *(Pics not yet available.) Is desoldering these caps straightforward? *Any special precautions multi-layered PCB traces? *Any special gotchas to keep in mind when ordering replacement caps from say Mouser? Thanks, Michael I've done this on motherboards; it's tedious, but practical. *The suggestions from others are good. *Here's a few things I discovered. While vacuum desoldering tools work well, you have to heat the board to the point where the solder on the ground lead melts all the way through the board. *The vacuum desoldering tools aren't real efficient at transfereing heat unless you add a little solder or flux to each lead you are going to unsolder. The technique I settled on was to use a 40 watt soldering iron with a chisel tip. *Heat up one leg, add a dab of Chip-Quik, rock the cap toward the opposite side. *Heat up the other leg, add Chip-Quik, rock cap to other side. *Repeat with the heating and rocking until the cap drops out. *While it's still hot, push an iron or stanless steel needle through the hole (I use a dissecting pick I got in the '60's). Remove the pick when the solder has cooled; reheat the other hole and use the needle. Make sure you keep a chart identifying which cap goes where. *Patience is necessary. *Make sure you clean up all stray solder. PlainBill Good advise and also make sure you take note of the polarity. Yes... I was having visions of getting the cap out then wondering, which way is negative... :-D Thanks y'all Michael |
#15
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general question: mainboard caps
On 9/21/2010 11:29 PM, Sergey Kubushyn wrote:
I recently restored and fully recapped two Kenwood KA-9100 amps. All the boards are phenolic and I used solder braid on them. And they are not multi layer boards with 0.010" traces. Jeff |
#16
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general question: mainboard caps
Michael wrote: Yes... I was having visions of getting the cap out then wondering, which way is negative... :-D Usually there's a circle printed on the board under each electrolytic capacitor, and the negative side is filled in, but Asus and Asrock boards are marked the opposite way, so the filled area indicates the positive lead instead. There are YouTube videos about soldering and desoldering, and BadCaps.net has a lot of information and also sells high-quality caps. I think they also have a YouTube video. In my novice opinion, a mainboard made with leaded solder needs a 40W iron to solder it, a 50W iron to desolder it, and lead-free boards need even more power. But a regular 50W iron can overheat its tip and turn it blue or oxidize it, which really hurts heat conduction. There are adjustable power irons for as little as $10, but I've found that cheap irons don't last long or don't deliver as much heat to the tip as good irons of the same power rating. BTW if you buy one off Ebay, check the voltage because many are made only for 220VAC. If you're going to spend much at all on an iron, consider getting a temperature- controlled, 70W Goot PX-201, about $50, which should be able to handle about anything, and Goot is a quality brand. Temperature-controlled is better than adjustable power. With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. Manual desoldering vacuums work best if you can hold them on one side of the board and the iron on the other side and see both sides at once. Vacuum bulbs don't suck nearly as well as spring plungers do, but the latter can strike and damage board at the moment the spring is released. Addng a short length of rubber tubing can prevent the damage. Copper desoldering braid works if it's the right width (enough to soak up all the solder from the hole in one try but not more, generally 2-3mm and the iron puts out plenty of heat. Cut off the used portion immediately after use so it won't absorb heat from the next joint. Don't pull out a lead unless all of the solder from the hole has been removed, and test by wiggling the lead side to side. Generally if all the solder doesn't come out in one try, it's best to fill the hole with 60/40 or 63/37 solder and start all over. Chip Quik may be the easiest and safest way to desolder because it melts at under 150F, but it costs about $1 per inch. Radio Shack sells an $11 desoldering iron with a vacuum bulb, and other sources have a similar tool that has a spring-loaded plunger vacuum instead. The Radio Shack iron doesn't seem to deliver quite enough heat to the tip for multilayer boards, but people have modified it with a better vacuum pump or by wrapping heat insulation above the tip. |
#17
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general question: mainboard caps
On Wed, 22 Sep 2010 05:05:19 +0000 (UTC), Sergey Kubushyn
wrote: Jeffrey Angus wrote: On 9/21/2010 11:29 PM, Sergey Kubushyn wrote: I recently restored and fully recapped two Kenwood KA-9100 amps. All the boards are phenolic and I used solder braid on them. And they are not multi layer boards with 0.010" traces. They are not. There is no such thing as _phenolic_ multi layer boards with 0.010" traces. Not yet. Some experiments in printed semiconductors and 3D circuits use multilayer boards. However they don't use solder. They're stapled together. They're also intended to be throw away assemblies, so I wouldn't worry about repair. BTW, solder braid is very useful on _ANY_ board, including multilayer ones with 0.010" traces. It requires some skills of course but everything does. I do use it all the time. I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). It's not the lack of skill. I have no problem using braid on large objects with small heat sinks. I have nothing but problems using braid on small objects attached to large heat sinks. I this case, there's a small leaded capacitor, connected to a rather large copper heat sink of the power bus inside the PCB. You can see the effect when unsoldering the capacitor leads. The ungrounded hot lead comes out easily. The grounded lead is far more difficult. If the capacitors are near the CPU and on a power bus, then both leads are difficult. Braid is also quite suitable for unsolder connections where the solder is easily accessible and exposed to the braid, such as large xformer pins, terminal strips, wire terminals, some IC sockets, tube sockets, etc. Also remember that this is for what appears to be a beginner at repair. It's easier to explain how to operate a solder sucker than braid. I forgot to mention the desoldering bulb, another device that barely works: http://www.amazon.com/Weller-Desoldering-Bulb-Solder-Off/dp/B00011TUZY The only good part is that it's great finger exercise (I play piano). I recently purchased one of the contrivances: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220664298701 It's a solder sucker hung on the back end of a hollow soldering iron. It took a while to discover what was wrong with this idea. The amount of vacuum generated is dependent on the unsuck to suck ratio of air volumes. With an ordinary solder sucker, where the tip is close to the piston, the ratio is rather large, thus offering a good vacuum. Not so with this contrivance, as the volume of the hollow tube adds to both volumes and results in much less vacuum. A larger diameter piston or shorter soldering iron barrel would have made it work better, but as it stands, the design sucks. 30 watts also seems underpowered, the tip is too big, and it takes 10 minutes to warm up. I haven't used it much, but I suspect that it will clog with dross near the entrance to the solder sucker. It is not the rifle that shoots way off the target, it is the shooter. True. However, I would rather use a guided missile (fancy desoldering station) than to go off plinking at the target (solder braid). -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#18
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general question: mainboard caps
On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote:
snip I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). It's not the lack of skill. snip My first "job" in electronics was in the back room of my barber's shop who had a little hobby business repairing electronics odds and ends. It was where I learned how to solder. Especially after being told by one of the barber's friends that I soldered like his grandmother That was in 1971. I was 16. -- Live Fast, Die Young and Leave a Pretty Corpse |
#19
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general question: mainboard caps
On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow
wrote: On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote: snip I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). It's not the lack of skill. snip My first "job" in electronics was in the back room of my barber's shop who had a little hobby business repairing electronics odds and ends. It was where I learned how to solder. Especially after being told by one of the barber's friends that I soldered like his grandmother That was in 1971. I was 16. That was a compliment. I started with an Ungar wood burner at about 14 years old. The first lesson I learned is that the power cord of the iron will melt and short when I place the iron on it. It was downhill from there as my father taught me to use a large copper gas fired furnace soldering thing used to make industrial sewing machine attachments. By comparison, the Ungar seemed easy. After several years of doing everything wrong, the high skool electric shop teacher introduced me to flux. Over the years, I learned the basics, like you can hold solder in your mouth, but don't try it with copper wire. Far too many Eico, Heathkit, and Knightkit constructions were great practice. I recently tried to teach a friends 14 year old brat how to solder. He's hopeless, but dedicated, and will eventually learn. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#20
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general question: mainboard caps
On Sep 22, 9:23*am, Jeff Liebermann wrote:
On Wed, 22 Sep 2010 05:05:19 +0000 (UTC), Sergey Kubushyn wrote: Jeffrey Angus wrote: On 9/21/2010 11:29 PM, Sergey Kubushyn wrote: I recently restored and fully recapped two Kenwood KA-9100 amps. All the boards are phenolic and I used solder braid on them. And they are not multi layer boards with 0.010" traces. They are not. There is no such thing as _phenolic_ multi layer boards with 0.010" traces. Not yet. *Some experiments in printed semiconductors and 3D circuits use multilayer boards. *However they don't use solder. *They're stapled together. *They're also intended to be throw away assemblies, so I wouldn't worry about repair. BTW, solder braid is very useful on _ANY_ board, including multilayer ones with 0.010" traces. It requires some skills of course but everything does. I do use it all the time. I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). *It's not the lack of skill. *I have no problem using braid on large objects with small heat sinks. *I have nothing but problems using braid on small objects attached to large heat sinks. *I this case, there's a small leaded capacitor, connected to a rather large copper heat sink of the power bus inside the PCB. *You can see the effect when unsoldering the capacitor leads. *The ungrounded hot lead comes out easily. *The grounded lead is far more difficult. *If the capacitors are near the CPU and on a power bus, then both leads are difficult. Braid is also quite suitable for unsolder connections where the solder is easily accessible and exposed to the braid, such as large xformer pins, terminal strips, wire terminals, some IC sockets, tube sockets, etc. * I noticed that one of the capacitor leads is connected to what looks like a fat copper trace (ground?) The other lead seems soldered to just a tiny little circle... if I hadn't looked closely, I might have soldered it to ground by mistake too... Also remember that this is for what appears to be a beginner at repair. *It's easier to explain how to operate a solder sucker than braid. Yes I'm a beginner at this, and thanks! I forgot to mention the desoldering bulb, another device that barely works: http://www.amazon.com/Weller-Desoldering-Bulb-Solder-Off/dp/B00011TUZY The only good part is that it's great finger exercise (I play piano). I heard that the bulb doesn't work very well. My dad has one. And hey, I play the piano too! Trying to learn how to play George Winston's piano solos... The Cradle is pretty straightforward, but, oh man, his variations on the Carol of the Bells is extremely tough! Michael |
#21
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general question: mainboard caps
On Wed, 22 Sep 2010 11:11:56 -0700, Jeff Liebermann wrote:
On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow wrote: On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote: snip I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). It's not the lack of skill. snip My first "job" in electronics was in the back room of my barber's shop who had a little hobby business repairing electronics odds and ends. It was where I learned how to solder. Especially after being told by one of the barber's friends that I soldered like his grandmother That was in 1971. I was 16. That was a compliment. I started with an Ungar wood burner at about 14 years old. The first lesson I learned is that the power cord of the iron will melt and short when I place the iron on it. It was downhill from there as my father taught me to use a large copper gas fired furnace soldering thing used to make industrial sewing machine attachments. By comparison, the Ungar seemed easy. After several years of doing everything wrong, the high skool electric shop teacher introduced me to flux. Over the years, I learned the basics, like you can hold solder in your mouth, but don't try it with copper wire. Far too many Eico, Heathkit, and Knightkit constructions were great practice. I recently tried to teach a friends 14 year old brat how to solder. He's hopeless, but dedicated, and will eventually learn. LOL! We had wood burners but I think I was only 10. I can't imagine the politics of selling those thing to children of that age as a child's toy these days. -- Live Fast, Die Young and Leave a Pretty Corpse |
#22
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general question: mainboard caps
Michael wrote:
Ok, thanks to everyone who replied. Seems doable... looks like I'm going shopping for a vacuum desolderer. Hi Michael! Makes repair surely easier . It's always my advice, but I don't have an desoldering-iron (vacuum) since then ;-). The 'right' stuff is expensive.... I have done some boards, desoldering the failing condensators by changing the soldering-iron from one pin to the other, pulling the capacitor side (pin) by side (pin), out of its placement. The new caps I pull into the same way.... Tin-solder I take only a tip..., just to have a better contact to the origin tin-solder of the mainboard, which can be tricky and sticky :-(. Some boards are easier, and you can desolder it with desoldering-lace (flex, cord). Plus, that the standard (yours) tin-solder will be adopted, too. -- Daniel Mandic |
#23
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general question: mainboard caps
On Wed, 22 Sep 2010 18:55:13 +0000 (UTC), Meat Plow
wrote: On Wed, 22 Sep 2010 11:11:56 -0700, Jeff Liebermann wrote: On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow wrote: On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote: snip I've been soldering for about 50 years, so I suspect I'm sufficiently experienced to have made all the usual mistakes (several times). It's not the lack of skill. snip My first "job" in electronics was in the back room of my barber's shop who had a little hobby business repairing electronics odds and ends. It was where I learned how to solder. Especially after being told by one of the barber's friends that I soldered like his grandmother That was in 1971. I was 16. That was a compliment. I started with an Ungar wood burner at about 14 years old. The first lesson I learned is that the power cord of the iron will melt and short when I place the iron on it. It was downhill from there as my father taught me to use a large copper gas fired furnace soldering thing used to make industrial sewing machine attachments. By comparison, the Ungar seemed easy. After several years of doing everything wrong, the high skool electric shop teacher introduced me to flux. Over the years, I learned the basics, like you can hold solder in your mouth, but don't try it with copper wire. Far too many Eico, Heathkit, and Knightkit constructions were great practice. I recently tried to teach a friends 14 year old brat how to solder. He's hopeless, but dedicated, and will eventually learn. LOL! We had wood burners but I think I was only 10. I can't imagine the politics of selling those thing to children of that age as a child's toy these days. I can't recall how old I was when I got the wood burner, so I guessed on the age. I may have been younger. Mine hand a huge ceramic heating element, with a diameter about the same as the handle. There was no way to put it down anywhere without seriously burning what it touched. The unplated tiny copper screw-in tip was a bad joke that pitted badly after a few hours of use. The handle got really hot. I had it for maybe 30 years and used it for cutting and welding plastic. By todays standards, the old woodburners are dangerous even for an adult. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#24
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general question: mainboard caps
On Wed, 22 Sep 2010 11:42:53 -0700 (PDT), Michael
wrote: I noticed that one of the capacitor leads is connected to what looks like a fat copper trace (ground?) The other lead seems soldered to just a tiny little circle... if I hadn't looked closely, I might have soldered it to ground by mistake too... Some of the traces and pads are VERY close to nearby grounds and other traces. Be careful and don't slop too much solder around when you install the replacement cap. I heard that the bulb doesn't work very well. My dad has one. Steal the bulb, throw it away, and get him a solder sucker. Better yet, steal just the teflon tip. It fits some solder suckers. hey, I play the piano too! Trying to learn how to play George Winston's piano solos... The Cradle is pretty straightforward, but, oh man, his variations on the Carol of the Bells is extremely tough! I can't read a note of music and scribble my own. My playing is awful but given a few centuries practice, it might improve: http://802.11junk.com/jeffl/music/ My Korg DDS-1 synthesizer slowly died over the last month and is scattered in pieces all over the living room. I can't tell what failed, but it's making strange noises and the LCD backlighting has quit. Yet another project. Playing music is the only thing that keeps me sane, which may explain this months rants on usenet. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#25
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general question: mainboard caps
On Sep 22, 1:09*pm, "Daniel Mandic" wrote:
Michael wrote: Ok, thanks to everyone who replied. *Seems doable... looks like I'm going shopping for a vacuum desolderer. Hi Michael! Makes repair surely easier . It's always my advice, but I don't have an desoldering-iron (vacuum) since then ;-). The 'right' stuff is expensive.... I have done some boards, desoldering the failing condensators by changing the soldering-iron from one pin to the other, pulling the capacitor side (pin) by side (pin), out of its placement. The new caps I pull into the same way.... Tin-solder I take only a tip..., just to have a better contact to the origin tin-solder of the mainboard, which can be tricky and sticky :-(. Some boards are easier, and you can desolder it with desoldering-lace (flex, cord). Plus, that the standard (yours) tin-solder will be adopted, too. -- Daniel Mandic That reminds me... is it a good idea or a bad idea to solder the new cap with normal (leaded) solder? Thanks, Michael |
#26
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general question: mainboard caps
larry moe 'n curly wrote:
With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. A good watered sponge does work. Good condition solder-tip expected... So many Tips and Tricks you gave, I don't think Michael will understand the halve of it ;-) -- Daniel Mandic |
#27
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general question: mainboard caps
Jeff Liebermann wrote:
I can't read a note of music and scribble my own. My playing is awful but given a few centuries practice, it might improve: http://802.11junk.com/jeffl/music/ My Korg DDS-1 synthesizer slowly died over the last month and is scattered in pieces all over the living room. I can't tell what failed, but it's making strange noises and the LCD backlighting has quit. Yet another project. Playing music is the only thing that keeps me sane, which may explain this months rants on usenet. Some people do have only one hit in their life, but. E.g. 'Scatman'. Or...!... 'Born to be Alive'! With this in mind, play your melodies and enjoy the time. I do so... [Yamaha AN1-X, KORG DSS-1, Wavestation, .....and some DiY, preferably analogue, in my mind! ;-) e.g. MiniMOOG, TR-909, Formant Synthesizer, etc., much work AND high costs....] -- Daniel Mandic |
#28
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general question: mainboard caps
Michael wrote:
That reminds me... is it a good idea or a bad idea to solder the new cap with normal (leaded) solder? Mainboards, AFAIK, are soldered in an solder bath. I don't know the temperature nor the solder-tin they use. Even that, I would have no idea what to do with the data ;-) I do by trying. Believing my skills (can excel to rubbish quality, if I don't keep the pace regarding IT motherboards) might help. But you can make some repairs if you dare, and save some money here and there. (I am starting to rhyme in english... :-)) Keep an eye, as other posters said (take a lens for example!), for solder- spots/patches/splotches, where they shouldn't be. By the way. Power capacitors are, I would say, arranged to the bottom side of the mainboard. The pins of the cap goes through the board. I have had similar thoughts as you... 8layer, 4layer special electronic, but, so long as I have had bringing back PC's, I am pretty sure power caps are to be found on the bottom side (physically on the top side, off course). -- Daniel Mandic |
#29
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general question: mainboard caps
On Sep 22, 2:00*pm, "Daniel Mandic" wrote:
larry moe 'n curly wrote: With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. A good watered sponge does work. Good condition solder-tip expected... So many Tips and Tricks you gave, I don't think Michael will understand the halve of it ;-) -- Daniel Mandic Dad always used a sponge (repaired TVs and radios decades ago) for solder work. I prefer a used tissue personally. (A sponge is such a waste.) Michael |
#30
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general question: mainboard caps
Michael wrote: On Sep 22, 2:00 pm, "Daniel Mandic" wrote: larry moe 'n curly wrote: With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. A good watered sponge does work. Good condition solder-tip expected... So many Tips and Tricks you gave, I don't think Michael will understand the halve of it ;-) -- Daniel Mandic Dad always used a sponge (repaired TVs and radios decades ago) for solder work. I prefer a used tissue personally. (A sponge is such a waste.) Then why is the industry standard for manufacturing? They can be rinsed out and turned over. Even with heavy use, they have a long life. Also, it is much easier to keep them damp that a dirty kleenex. You do not want the sponge to be sopping wet, just damp enough to keep it from burning. If it is too wet it can cause the iron plating to crack, and cause the tip to have a very short life. -- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them. |
#31
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general question: mainboard caps
On Sep 22, 8:52*pm, "Michael A. Terrell"
wrote: Michael wrote: On Sep 22, 2:00 pm, "Daniel Mandic" wrote: larry moe 'n curly wrote: With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. A good watered sponge does work. Good condition solder-tip expected.... So many Tips and Tricks you gave, I don't think Michael will understand the halve of it ;-) -- Daniel Mandic Dad always used a sponge (repaired TVs and radios decades ago) for solder work. *I prefer a used tissue personally. *(A sponge is such a waste.) * *Then why is the industry standard for manufacturing? *They can be What? There is still electronics manufacturing in the United States? 8-D |
#32
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general question: mainboard caps
Michael wrote: What? There is still electronics manufacturing in the United States? Yes, just not $10 radios or $20 TVs. -- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them. |
#33
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general question: mainboard caps
On Wed, 22 Sep 2010 13:57:28 -0700 (PDT), Michael
wrote: That reminds me... is it a good idea or a bad idea to solder the new cap with normal (leaded) solder? No. It's highly likely that the motherboard uses RoHS blessed unleaded solder. Mixing solder types results in a rather dull looking cold solder joint. However, if you suck away all of the solder on the pad, you can probably get away with switching solder types, but I wouldn't bother. Just get the right solder. Incidentally, I have two soldering irons on my bench... one for each type of solder. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#34
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general question: mainboard caps
On Sep 22, 9:40*pm, "Michael A. Terrell"
wrote: Michael wrote: What? *There is still electronics manufacturing in the United States? * *Yes, just not $10 radios or $20 TVs. Will wonders never cease... ok, I'm taking half of my wife's dishwashing sponge then... Michael |
#35
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general question: mainboard caps
On Sep 21, 6:51*pm, Jeff Liebermann wrote:
On Tue, 21 Sep 2010 11:28:35 -0700 (PDT), Michael wrote: Ok, thanks to everyone who replied. *Seems doable... looks like I'm going shopping for a vacuum desolderer. While a proper vacuum desoldering station is nice, you can get away with using a solder sucker. http://www.amazon.com/SOLDER-SUCKER-DESOLDERING-DESOLDER-REMOVAL/dp/B... It requires some practice at both using and cleaning. *I use one when I'm too lazy to fire up the desoldering station. Someone suggested using solder braid. *I disagree. *I've lifted so many traces and pads from the board with solder braid, that I won't use it unless I'm depserate. Don't forget the stainless steel needle or pin for cleaning the hole. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 #http://802.11junk.com* * * * * * * #http://www.LearnByDestroying.com* * * * * * * AE6KS I'm with you on the braid but it _is_ good for cleaning surface mount pads before installing the new component. A Metcal with an STTC-126 tip is about the best if you _don't_ have a vacuum desoldering station. The small tip can fit partway into the hole after the component is out and then you can use an old fashioned solder sucker with excellent results. G² |
#36
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general question: mainboard caps
Michael wrote: On Sep 22, 9:40 pm, "Michael A. Terrell" wrote: Michael wrote: What? There is still electronics manufacturing in the United States? Yes, just not $10 radios or $20 TVs. Will wonders never cease... ok, I'm taking half of my wife's dishwashing sponge then... Is it a real sponge, or just a fake plastic version? Spend the couple bucks and by one treated for cleaning soldering iron tips. -- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them. |
#37
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general question: mainboard caps
On Wed, 22 Sep 2010 23:15:47 -0700 (PDT), Michael
wrote: Will wonders never cease... ok, I'm taking half of my wife's dishwashing sponge then... Don't do that. It's probably a plastic immitation sponge. It will melt or burn nicely, even with sufficient water. The real soldering iron sponges are cellulose and cost about $1 online. You can find cellulose sponges at the market if you read the label carefully. The other problem is that the household sponges are too thick. After a few minutes, the water will dribble back into the base of the sponge, leaving the top of the sponge quite dry and easy to burn. Too thin is also a problem as you don't want to submerge the soldering iron tip into a puddle of water. I'm too lazy to walk downstairs and measure the official Weller sponge thickness, but try to get it close. For a holder, I find glass ashtrays to be perfect. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#38
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general question: mainboard caps
On Sep 21, 9:44*am, Jeff Liebermann wrote:
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael wrote: I've got a couple of Intel boards (D865PERL) that have one bad electrolytic capacitor each. *One board stopped working; the other still works, but has a bulging cap close to the CPU area. *(Pics not yet available.) My experience is that if you have the usual 8-10 identical capacitors on the motherboard, and one is visibly defective, then the others are highly likely to fail very soon. *I replace *ALL* the caps of a specific type. *In particular, the caps around the CPU tend to die, because of the heat and the high ripple current. *Typically, I'll replace 10 to 15 caps. Is desoldering these caps straightforward? It varies. *Some boards are very easy to unsolder. *Others have smaller holes for the leaded parts and are more difficult. *A vacuum desoldering station is best. *Use plenty of heat and some liquid flux so that you don't pull the plated thru hole out with the capacitor. If you see a copper colored ring around a capacitor lead, you've probably killed the board. Any special precautions multi-layered PCB traces? If you don't have a tip that will heat both leads at the same time, or don't have 3 arms so that you can use two soldering irons, all is not lost. *I heat up one lead, and rock the capacitor in the opposite direction. *After it moves a little, I heat the other lead, and rock it in the opposite direction. *Don't use brute force or you'll rip out the plated through holes. *Eventually, it comes out. * One lead is usually grounded where the large copper area acts as an effective heat sink. *This lead will be more difficult to unsolder than the hot lead (usually +). *I use a big, wide (1/4"), hot (850C), chisel tip. *Plenty of heat, and work fast. *This will take some practice. *Find an old PCB and practice a little before attacking the Intel motherboard. Any special gotchas to keep in mind when ordering replacement caps from say Mouser? 105C Low-ESR. *Watch the case dimensions and lead spacing. *If it will fit, try to buy the next higher voltage rating. *I'm partial to Panasonic but will use Rubycon. *Digikey, Mouser, and eBay (in that order). *I sometimes use polymer caps as replacements, when the motherboard is worth fixing and the customer doesn't care about the cost. *Also, think about buying an ESR tester if you're going to make a habit of this. http://www.badcaps.net http://www.afrotechmods.com/groovy/capacitor_replacement/capacitor_re... http://en.wikipedia.org/wiki/Capacitor_plague http://www.capacitorlab.com -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558 Thanks to all for your expertise in de-soldering...there is a world of experience here, and worth much. I have never had luck with braided wire...but evidently is works for some. (I never have any luck with super-glue either!) |
#39
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general question: mainboard caps
On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa
wrote: Thanks to all for your expertise in de-soldering...there is a world of experience here, and worth much. I have never had luck with braided wire...but evidently is works for some. (I never have any luck with super-glue either!) Super-glue doesn't do very well for desoldering (or soldering) a printed circuit boards. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#40
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general question: mainboard caps
On Sep 22, 2:12*am, "larry moe 'n curly"
wrote: Michael wrote: Yes... I was having visions of getting the cap out then wondering, which way is negative... :-D Usually there's a circle printed on the board under each electrolytic capacitor, and the negative side is filled in, but Asus and Asrock boards are marked the opposite way, so the filled area indicates the positive lead instead. There are YouTube videos about soldering and desoldering, and BadCaps.net has a lot of information and also sells high-quality caps. *I think they also have a YouTube video. In my novice opinion, a mainboard made with leaded solder needs a 40W iron to solder it, a 50W iron to desolder it, and lead-free boards need even more power. *But a regular 50W iron can overheat its tip and turn it blue or oxidize it, which really hurts heat conduction. *There are adjustable power irons for as little as $10, but I've found that cheap irons don't last long or don't deliver as much heat to the tip as good irons of the same power rating. *BTW if you buy one off Ebay, check the voltage because many are made only for 220VAC. * If you're going to spend much at all on an iron, consider getting a temperature- controlled, 70W Goot PX-201, about $50, which should be able to handle about anything, and Goot is a quality brand. * Temperature-controlled is better than adjustable power. *With any iron, a chisel tip, about 2mm - 2.5mm wide, works better than a conical tip, and tips are best cleaned with curly brass hair or a damp paper towel, not a sponge. Manual desoldering vacuums work best if you can hold them on one side of the board and the iron on the other side and see both sides at once. *Vacuum bulbs don't suck nearly as well as spring plungers do, but the latter can strike and damage board at the moment the spring is released. *Addng a short length of rubber tubing can prevent the damage. Copper desoldering braid works if it's the right width (enough to soak up all the solder from the hole in one try but not more, generally 2-3mm and the iron puts out plenty of heat. *Cut off the used portion immediately after use so it won't absorb heat from the next joint. Don't pull out a lead unless all of the solder from the hole has been removed, and test by wiggling the lead side to side. *Generally if all the solder doesn't come out in one try, it's best to fill the hole with 60/40 or *63/37 solder and start all over. Chip Quik may be the easiest and safest way to desolder because it melts at under 150F, but it costs about $1 per inch. Radio Shack sells an $11 desoldering iron with a vacuum bulb, and other sources have a similar tool that has a spring-loaded plunger vacuum instead. *The Radio Shack iron doesn't seem to deliver quite enough heat to the tip for multilayer boards, but people have modified it with a better vacuum pump or by wrapping heat insulation above the tip. Went shopping... got a plunger for $11 at Fry's. Harbor Freight has a 180W solder gun for $10... remembered pointers here on high power for Pb-free solder... is the gun a good idea, or too hot? |
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