Computer motherboard repair soldering

1
I need some recommendations from y’all especially if you have some experience in soldering on motherboards. I have a computer with a bad capacitor I need to remove and replace. The computer has not been in service for a long time, but contains many of my drafting programs and other files. Since the pandemic has really killed my income from the office I work at, in reality one foot out the door, since my hours are really down to a few hours a week if that. I can’t rely on using the office programs much longer. So here’s what I want to do, I know which capacitor is blown and I intend to replace it. I need recommendations on a soldering iron to use on this task. I plan to buy some spare parts from old boards or if I can find one a new capacitor.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

3
I remember my dad soldering all the components to a radio kit in the 1960’s. It had a board and a bunch of transistors, capacitors and what nots. LoL. The radio had short wave, long wave, and fm/am bands. Worked great and it only got lost in one of our numerous moves during my youth. Wish I could have kept it. Anything can be fixed, I’ve made a habit of doing just that and I really don’t feel intimidated by this task. I need a quality soldering iron with proper small tips. The capacitor is pretty easy to get to once the board is removed. It’s the simplest solution to my immediate problem without having to redo a bunch of setup. This computer cannot access the internet so I need it to just boot up again.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

5
featureless wrote: Sat Feb 27, 2021 10:28 am I'm of no help on the soldering. But it you have another computer, could you pull the drive and stuff it in the other to get that data off?
Some files perhaps, but since it was my drafting machine it’s not going to do me much good. I don’t want to start reset up on programs to find it wants an internet connection.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

6
https://linustechtips.com/topic/603395- ... apacitors/

Some good tips at this link. Been years since I've messed with PCboard repairs. I've thrown all my caps and resistors away along with whatever tools I had. Good luck. It was always hit and miss. On one old PC tower I was lucky to find a replacement motherboard on ebay. That puppy still running Win 98SE.
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Re: Computer motherboard repair soldering

7
Wino wrote: Sat Feb 27, 2021 1:46 pm https://linustechtips.com/topic/603395- ... apacitors/

Some good tips at this link. Been years since I've messed with PCboard repairs. I've thrown all my caps and resistors away along with whatever tools I had. Good luck. It was always hit and miss. On one old PC tower I was lucky to find a replacement motherboard on ebay. That puppy still running Win 98SE.
Thanks. The link pointed out the issue about the right soldering iron. I know that it is crucial to what I do. My fallback on this operation is I will buy a motherboard to match perhaps two. One to repair the old one and the other in case I don’t succeed. The computer is extremely old so boards are cheap.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

8
sikacz wrote: Sat Feb 27, 2021 9:10 am I need some recommendations from y’all especially if you have some experience in soldering on motherboards. I have a computer with a bad capacitor I need to remove and replace. The computer has not been in service for a long time, but contains many of my drafting programs and other files. Since the pandemic has really killed my income from the office I work at, in reality one foot out the door, since my hours are really down to a few hours a week if that. I can’t rely on using the office programs much longer. So here’s what I want to do, I know which capacitor is blown and I intend to replace it. I need recommendations on a soldering iron to use on this task. I plan to buy some spare parts from old boards or if I can find one a new capacitor.
The soldering iron is less important. You'll need soldering heat sink tape--it's a brown clear plastic tape--look for Kaptan Tape and other brands. You can search Amazon for "Soldering Heat Tape" as well. This the most important thing you'll need and you'll need to cover every nearby component and circuit line with it to protect them. Otherwise you'll blow up more than the capacitor. It's great stuff. I actually was able to replace the micro-usb charging/data port on a Samsung Galaxy phone with it, successfully.

You will also need a de-soldering vacuum tool. Some are as simple as a squeeze bulb you release to suck out the old solder, others use a spring-loaded plunger you release--they work better.
EDIT: I forgot to mention de-soldering tape--it's a flat copper braid that the old solder bonds to.

You'll also want some small heat sink clips to protect the new capacitor. You can use locking forceps as well.
For soldering you'll want either a pencil iron or a soldering gun. Dial-in pencil irons are the best, but an expensive investment.

You'll want non-acid flux core electronics solder. Solid core is fine but you'll need a small can of flux. Do NOT use plumbing solder or flux, only electronics.
Finally, you'll want to "tin" the leads of the new component--protecting it with a heat sink on each lead, heat the lead till it melts and sucks the solder around it in a very thin layer.

Work as quickly as you can, safely. Dawdling over a solder increases the chances of fucking up (Ask how I know...better yet, DONT!).
I've done a lot of electronic soldering, but the phone's charging/dataport was the most complex as there are 10 or more tiny leads.
I'm not nearly as good at plumbing soldering, but just 2 days ago I had to replace a cut-off valve under our kitchen sink. Luckily I had a spare one, and it ain't a pretty sweat job, but it's sealed and doesn't leak.
Hope this helps.

Kaptan Tape or its equivalent!
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

Re: Computer motherboard repair soldering

9
sikacz wrote: Sat Feb 27, 2021 1:55 pm
Wino wrote: Sat Feb 27, 2021 1:46 pm https://linustechtips.com/topic/603395- ... apacitors/

Some good tips at this link. Been years since I've messed with PCboard repairs. I've thrown all my caps and resistors away along with whatever tools I had. Good luck. It was always hit and miss. On one old PC tower I was lucky to find a replacement motherboard on ebay. That puppy still running Win 98SE.
Thanks. The link pointed out the issue about the right soldering iron. I know that it is crucial to what I do. My fallback on this operation is I will buy a motherboard to match perhaps two. One to repair the old one and the other in case I don’t succeed. The computer is extremely old so boards are cheap.
Purchase the exact same motherboard and replace it carefully. Don't bother trying to replace the cap unless you want a fun project.

I used to work at a company that "repaired" motherboards. These were mostly MBs from specialized machines with expensive MBs. Even in the 1990s, it was cheaper and more reliable for a home user to just replace the board. It really depends on the board, but an older PC board is inexpensive.

I would personally suggest that you upgrade the board with something that can use your existing graphics card and peripherals. If you just want your old machine running again, just replace the old board with the exact same board.
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Re: Computer motherboard repair soldering

10
YankeeTarheel wrote: Sat Feb 27, 2021 2:13 pm
sikacz wrote: Sat Feb 27, 2021 9:10 am I need some recommendations from y’all especially if you have some experience in soldering on motherboards. I have a computer with a bad capacitor I need to remove and replace. The computer has not been in service for a long time, but contains many of my drafting programs and other files. Since the pandemic has really killed my income from the office I work at, in reality one foot out the door, since my hours are really down to a few hours a week if that. I can’t rely on using the office programs much longer. So here’s what I want to do, I know which capacitor is blown and I intend to replace it. I need recommendations on a soldering iron to use on this task. I plan to buy some spare parts from old boards or if I can find one a new capacitor.
The soldering iron is less important. You'll need soldering heat sink tape--it's a brown clear plastic tape--look for Kaptan Tape and other brands. You can search Amazon for "Soldering Heat Tape" as well. This the most important thing you'll need and you'll need to cover every nearby component and circuit line with it to protect them. Otherwise you'll blow up more than the capacitor. It's great stuff. I actually was able to replace the micro-usb charging/data port on a Samsung Galaxy phone with it, successfully.

You will also need a de-soldering vacuum tool. Some are as simple as a squeeze bulb you release to suck out the old solder, others use a spring-loaded plunger you release--they work better.
EDIT: I forgot to mention de-soldering tape--it's a flat copper braid that the old solder bonds to.

You'll also want some small heat sink clips to protect the new capacitor. You can use locking forceps as well.
For soldering you'll want either a pencil iron or a soldering gun. Dial-in pencil irons are the best, but an expensive investment.

You'll want non-acid flux core electronics solder. Solid core is fine but you'll need a small can of flux. Do NOT use plumbing solder or flux, only electronics.
Finally, you'll want to "tin" the leads of the new component--protecting it with a heat sink on each lead, heat the lead till it melts and sucks the solder around it in a very thin layer.

Work as quickly as you can, safely. Dawdling over a solder increases the chances of fucking up (Ask how I know...better yet, DONT!).
I've done a lot of electronic soldering, but the phone's charging/dataport was the most complex as there are 10 or more tiny leads.
I'm not nearly as good at plumbing soldering, but just 2 days ago I had to replace a cut-off valve under our kitchen sink. Luckily I had a spare one, and it ain't a pretty sweat job, but it's sealed and doesn't leak.
Hope this helps.

Kaptan Tape or its equivalent!
Thanks. I’ll look into all of the above.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

11
K9s wrote: Sat Feb 27, 2021 2:25 pm
sikacz wrote: Sat Feb 27, 2021 1:55 pm
Wino wrote: Sat Feb 27, 2021 1:46 pm https://linustechtips.com/topic/603395- ... apacitors/

Some good tips at this link. Been years since I've messed with PCboard repairs. I've thrown all my caps and resistors away along with whatever tools I had. Good luck. It was always hit and miss. On one old PC tower I was lucky to find a replacement motherboard on ebay. That puppy still running Win 98SE.
Thanks. The link pointed out the issue about the right soldering iron. I know that it is crucial to what I do. My fallback on this operation is I will buy a motherboard to match perhaps two. One to repair the old one and the other in case I don’t succeed. The computer is extremely old so boards are cheap.
Purchase the exact same motherboard and replace it carefully. Don't bother trying to replace the cap unless you want a fun project.

I used to work at a company that "repaired" motherboards. These were mostly MBs from specialized machines with expensive MBs. Even in the 1990s, it was cheaper and more reliable for a home user to just replace the board. It really depends on the board, but an older PC board is inexpensive.

I would personally suggest that you upgrade the board with something that can use your existing graphics card and peripherals. If you just want your old machine running again, just replace the old board with the exact same board.
The problem is I have no intention of upgrading to newer software from AutoCAD. These were licensed to me and upgrading to new is beyond my means. Also, these programs do everything needed to produce construction documentation and works with all my equipment. At 61 years, I’m pretty good even with the latest versions, but I also know most people in an office environment never used the capability of the older versions which is pretty extensive. The problem with just matching the old board which I will do is the boot up. The CMOS on the old board is setup to work as is. A new board may have hiccups with configuration and require updates to the board through an internet connection. This would not be a good idea in my case.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

12
If you know for certain it's the cap, replacement of a non-surface mount component is not hard. You may want practice on some other circuit board, like out of a dead radio, just to get the feel of de-soldering.
Also find videos on electronics, like older stereos and radios. YouTube is full of them.
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

Re: Computer motherboard repair soldering

13
YankeeTarheel wrote: Sat Feb 27, 2021 3:19 pm If you know for certain it's the cap, replacement of a non-surface mount component is not hard. You may want practice on some other circuit board, like out of a dead radio, just to get the feel of de-soldering.
Also find videos on electronics, like older stereos and radios. YouTube is full of them.
I'm absolutely sure. It was visibly apparent and when I pushed in the top, it made an effort to start. Good advice. Will do.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

14
sikacz wrote: Sat Feb 27, 2021 3:56 pm
YankeeTarheel wrote: Sat Feb 27, 2021 3:19 pm If you know for certain it's the cap, replacement of a non-surface mount component is not hard. You may want practice on some other circuit board, like out of a dead radio, just to get the feel of de-soldering.
Also find videos on electronics, like older stereos and radios. YouTube is full of them.
I'm absolutely sure. It was visibly apparent and when I pushed in the top, it made an effort to start. Good advice. Will do.
There is always the other question: WHY did it fail? Is something else that failed causing it to fail? If the new one fails, that is probably the REAL problem.
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

Re: Computer motherboard repair soldering

15
YankeeTarheel wrote: Sat Feb 27, 2021 5:23 pm
sikacz wrote: Sat Feb 27, 2021 3:56 pm
YankeeTarheel wrote: Sat Feb 27, 2021 3:19 pm If you know for certain it's the cap, replacement of a non-surface mount component is not hard. You may want practice on some other circuit board, like out of a dead radio, just to get the feel of de-soldering.
Also find videos on electronics, like older stereos and radios. YouTube is full of them.
I'm absolutely sure. It was visibly apparent and when I pushed in the top, it made an effort to start. Good advice. Will do.
There is always the other question: WHY did it fail? Is something else that failed causing it to fail? If the new one fails, that is probably the REAL problem.
Overheated I suspect. It’s fan went on overdrive sometimes when it was connected to the internet. It’ll never be connected to the internet again. So that’s not an issue anymore. It was strange it would do it only while connected. Malicious software attack possibly.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Computer motherboard repair soldering

16
One thing to consider is the likelihood of other capacitors being on the edge of failure; depending upon the age of your motherboard, you may have a bunch more failure-prone caps just waiting to give out.

From approx. 1999 to 2003 or so, there were a lot of "bargain" electrolytic capacitors with labels from previously unknown manufacturers used in computers and other consumer devices - their lifespan was considerably shorter than they should have been, and they started failing rapidly. Lots of computer manufacturers got hit by warranty repairs; in one case I was involved in, Dell eventually replaced (under warranty) virtually every motherboard out of a school district's purchase of 600 computers.

(Look up "Capacitor Plague" for the story... It's a tale of failed industrial espionage and intellectual property theft of erroneous information, and the fallout which resulted.)

As to a replacement motherboard needing Internet access to upgrade firmware, this may not be the case; many older ones would have you download the upgrade and unpack it to a floppy disk or burn to a CD-ROM, then boot the computer from that to do the upgrade. Indeed, depending upon the motherboard and upgrade features, it may not even be necessary; for example, an firmware upgrade to the network card when you aren't going to be using it.

Re: Computer motherboard repair soldering

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OTOH, adding more or bigger higher-flow fans may help, too. I'm a big devotee of Noctua fans which are insanely quiet but flow a lot of air. My wife's PC is an older Alienware box that has been upgraded a couple of times and I replaced the MB a couple of years ago. I've since replaced 2 of the fans with Noctuas that both quieted it down and improved cooling. I have it as the CPU fan in my current rig, --ASRock MB and AMD Razor CPU, as does my son. I even replaced the little 1" fan in a surveillance DVR with a Noctua because the original could wake the dead AND didn't flow nearly enough air.

There are other great, quiet fans out there but I've had a 100% good experience with multiple Noctua fans.

BTW, if you want to build your own rig, this is a GREAT website for identifying compatible components, including the case, in all different price ranges from "destitute" to "monstrous" from $250 to $4100, less externals (Monitor, keyboard, mouse, speakers, etc) https://www.logicalincrements.com/
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Re: Computer motherboard repair soldering

19
Former electronics tech here. Speed is the key here when doing such a replacement. The suggestion to use a vacuum tool for the old solder is a very good one and one that I used to use a lot when repairing circuit boards. Keep the soldering iron on the contacts for just long enough to melt the solder, so that you don't end up lifting up the contact(s).

With that said, it can be done, plenty of others have done it, and it doesn't take long to replace all the capacitors. It's a good idea to do so, actually, as they're all the same age. Most motherboard failures that I've seen are due to the electrolytic capacitors simply wearing out over time.
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Re: Computer motherboard repair soldering

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CowboyT wrote: Sun Feb 28, 2021 5:20 pm Former electronics tech here. Speed is the key here when doing such a replacement. The suggestion to use a vacuum tool for the old solder is a very good one and one that I used to use a lot when repairing circuit boards. Keep the soldering iron on the contacts for just long enough to melt the solder, so that you don't end up lifting up the contact(s).

With that said, it can be done, plenty of others have done it, and it doesn't take long to replace all the capacitors. It's a good idea to do so, actually, as they're all the same age. Most motherboard failures that I've seen are due to the electrolytic capacitors simply wearing out over time.
Agree 100%. Vacuum desoldering tools and desoldering braid make a good combo. And always tin the leads before attaching them to a circuit board. I've also seen resisters blow, but that's on audio equipment.
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

Re: Computer motherboard repair soldering

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Heretic wrote: Sun Feb 28, 2021 9:24 pm Oh, yes - a simple thing, but easy to overlook...

Don't install the new electrolytic caps backward.

I did this once on a power supply for a tube-type Ham radio transceiver; my cat was not amused by an exploding capacitor, vacating the area at high speed.
Electrolytics are polarized. But other foil caps aren't polarized.
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

Re: Computer motherboard repair soldering

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Heretic wrote: Mon Mar 01, 2021 12:01 am Yup - I was just referring to electrolytic capacitors.

An additional lesson there was that schematics sometime have errors, and it's best to put the new component in the same orientation as the one being replaced.
Sometimes, if you're lucky, the circuit board will have a "+" and "-" printed on it, along with other data.
""If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you." -- LBJ

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