Home |
Search |
Today's Posts |
|
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. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
bulging top capacitors
In trying to figure out why this atx pc won't start, I carefully look ed
at the motherboard. Some of the blue 'can' capacitors are straight across the top, with the X shape. But others are bulged up. Some have a smudge of some yellow material on the bulged tops, and one has a smudge of black. Is this normal, or a sign of failure? Thanks. |
#2
|
|||
|
|||
Time for a new motherboard. There is a known problem with poor quality
capacitors from about 2 years ago on many brands of motherboards. Pull the CPU now before it gets fried and buy a new mother board. |
#3
|
|||
|
|||
"Al" wrote in message . .. In trying to figure out why this atx pc won't start, I carefully look ed at the motherboard. Some of the blue 'can' capacitors are straight across the top, with the X shape. But others are bulged up. Some have a smudge of some yellow material on the bulged tops, and one has a smudge of black. Is this normal, or a sign of failure? Thanks. You've got a board made during the bad electrolyte fiasco, replace all the electrolytics on the board, the bulging ones are completely shot, the rest of them WILL fail shortly. Be sure to clean up the electrolyte that leaked out, it's corrosive. |
#4
|
|||
|
|||
wrote in message ups.com... Time for a new motherboard. There is a known problem with poor quality capacitors from about 2 years ago on many brands of motherboards. Pull the CPU now before it gets fried and buy a new mother board. Why not repair it? I've fixed a whole pile of motherboards with this problem, never cost me more than about 15 bucks. THey can be tricky to desolder though, I had to use a 140W Weller on the ones with a large ground or vcc plane. |
#5
|
|||
|
|||
Al wrote:
In trying to figure out why this atx pc won't start, I carefully look ed at the motherboard. Some of the blue 'can' capacitors are straight across the top, with the X shape. But others are bulged up. Some have a smudge of some yellow material on the bulged tops, and one has a smudge of black. Is this normal, or a sign of failure? Thanks. See: http://www.spectrum.ieee.org/WEBONLY...eb03/ncap.html I've repaired some such boards, and had one repaired by the manufacturer at reasonable cost; whether doing so is worthwhile in your particular case depends on factors (like cost and the hassle of switching machines) that only you can decide. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#6
|
|||
|
|||
|
#7
|
|||
|
|||
"James Sweet" wrote in message news:gelId.13643$IP6.13358@trnddc05... wrote in message ups.com... Time for a new motherboard. There is a known problem with poor quality capacitors from about 2 years ago on many brands of motherboards. Pull the CPU now before it gets fried and buy a new mother board. Why not repair it? I've fixed a whole pile of motherboards with this problem, never cost me more than about 15 bucks. THey can be tricky to desolder though, I had to use a 140W Weller on the ones with a large ground or vcc plane. Probably because you can buy a new motherboard cheaper than a set of new capacitors for the older one. And then there's the added issue of the faulty capacitors over-stressing the regulators making them go thermally intermittent too, resulting in hours of wasted time spent changing the capacitors only to find the mobo is no better or even worse than it was before you started. More info about bad mobo caps here http://badcaps.net/ |
#8
|
|||
|
|||
Why not fix it? The replacement cost of a motherboard that will take a
cpu and memory from a couple of years ago is what, $45 for a good one and it will be upgradeable to the newer and faster cpu come upgrade time. Then there is the opportunity cost of the time involved. If it takes one hour to replace all the capacitors on the board, and the board does wind up being good, how much was that one hour worth? |
#9
|
|||
|
|||
Harvey wrote:
"James Sweet" wrote in message news:gelId.13643$IP6.13358@trnddc05... wrote in message roups.com... Time for a new motherboard. There is a known problem with poor quality capacitors from about 2 years ago on many brands of motherboards. Pull the CPU now before it gets fried and buy a new mother board. Why not repair it? I've fixed a whole pile of motherboards with this problem, never cost me more than about 15 bucks. THey can be tricky to desolder though, I had to use a 140W Weller on the ones with a large ground or vcc plane. Probably because you can buy a new motherboard cheaper than a set of new capacitors for the older one. And then there's the added issue of the faulty capacitors over-stressing the regulators making them go thermally intermittent too, resulting in hours of wasted time spent changing the capacitors only to find the mobo is no better or even worse than it was before you started. More info about bad mobo caps here http://badcaps.net/ The flip side is that the price of the motherboard can be irrelevant compared to the cost of new memory (since current motherboards often use a different sort) and the time to reinstall software and get everything working as before. And capacitors are pretty cheap; you ought to be able to replace them all for under 30 bucks +/-. It's not an easy call, but I've done a couple of replacements, and they've worked well for me. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#12
|
|||
|
|||
Art wrote:
IMHO, after the period of time it has taken for these caps to fail, and probably contribute to other damage, would it not be apparent that one should consider upgrading to a faster CPU, more memory, and new motherboard that has the USB2 feature,etc built in. I have done many computers this way for less than $200 USD and have a fine, faster, more reliable piece of equipment afterwards. Sure -- been there, done that. But I've also been in the situation where I've done what seemed like a simple upgrade and found that key pieces of software could no longer be made to run due to differences in the BIOS, etc. Each case must be evaluated on its own merits. "Just my 2 cents worth", of course,being a technician I have resoldered IDE connectors, SMD regulators and components, replaced caps, etc just to get a unit operational. Then, after a period of time find out that other devices indeed were stressed, inclusive of the power supplies. "CJT" wrote in message ... wrote: Why not fix it? The replacement cost of a motherboard that will take a cpu and memory from a couple of years ago is what, $45 for a good one and it will be upgradeable to the newer and faster cpu come upgrade time. Then there is the opportunity cost of the time involved. If it takes one hour to replace all the capacitors on the board, and the board does wind up being good, how much was that one hour worth? In my experience, finding and installing a suitable replacement motherboard will take about as long or longer. That it's "upgradeable to the newer and faster cpu" probably means it uses a different chipset, which means the OS may need reinstallation, too. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#13
|
|||
|
|||
"Harvey" wrote in message ... "James Sweet" wrote in message news:gelId.13643$IP6.13358@trnddc05... wrote in message ups.com... Time for a new motherboard. There is a known problem with poor quality capacitors from about 2 years ago on many brands of motherboards. Pull the CPU now before it gets fried and buy a new mother board. Why not repair it? I've fixed a whole pile of motherboards with this problem, never cost me more than about 15 bucks. THey can be tricky to desolder though, I had to use a 140W Weller on the ones with a large ground or vcc plane. Probably because you can buy a new motherboard cheaper than a set of new capacitors for the older one. Where can you buy a new motherboard for less than $15? And then there's the added issue of the faulty capacitors over-stressing the regulators making them go thermally intermittent too, resulting in hours of wasted time spent changing the capacitors only to find the mobo is no better or even worse than it was before you started. I've *never* run into a board that was intermittant after replacing the caps, I suppose it could happen but it's rare. I say either repair the board and keep it out of the landfill, or get a new board, CPU, RAM, etc to upgrade to a newer generation. |
#14
|
|||
|
|||
"Art" wrote in message ... IMHO, after the period of time it has taken for these caps to fail, and probably contribute to other damage, would it not be apparent that one should consider upgrading to a faster CPU, more memory, and new motherboard that has the USB2 feature,etc built in. I have done many computers this way for less than $200 USD and have a fine, faster, more reliable piece of equipment afterwards. It's certainly an option if you need a faster machine, but in a lot of cases $15 to get the computer back online vs $200 plus a bunch of time reinstalling the OS and all the applications (or if you get really lucky, a few tricks to reinstall the drivers), replacing the caps starts to look appealing. |
#15
|
|||
|
|||
The other thing to consider is if it's running XP it uwill not/u migrate to
a new mobo. You must reinstall. Any apps that have significant registry entries also will need to be reinstalled. If you're running 98 and change the mobo you need to start in safe mode and remove all references to the old mobo resources. If you don't you might get nagged by a BSOD once in a while. XP won't even get into safe mode with such a drastic hardware change. While the hardware change bothers 98, if you can manage not to reinstall it your apps will run right. The exception might be certain games if you wind up with a different vidcard. Actually anyone who's still running 98 is doing so for a very good reason. JURB |
#16
|
|||
|
|||
On 23-Jan-2005, CJT wrote: "Just my 2 cents worth", of course,being a technician I have resoldered IDE connectors, SMD regulators and components, replaced caps, etc just to get a unit operational. Then, after a period of time find out that other devices indeed were stressed, inclusive of the power supplies. "CJT" wrote in message ... wrote: Why not fix it? The replacement cost of a motherboard that will take a cpu and memory from a couple of years ago is what, $45 for a good one and it will be upgradeable to the newer and faster cpu come upgrade time. It's no easy task to replace all the caps on a multi-layer board with plated through holes. You are likely to end up with a dead board. Try fault tracing on that one. |
#17
|
|||
|
|||
|
#18
|
|||
|
|||
Harvey wrote:
Probably because you can buy a new motherboard cheaper than a set of new capacitors for the older one. That's nonsense. A handfull capacitors will cost between 10 and 25 dollars, a motherboard will cost between 30 and 150 dollars. And then there's the added issue of the faulty capacitors over-stressing the regulators making them go thermally intermittent too, resulting in hours of wasted time spent changing the capacitors only to find the mobo is no better or even worse than it was before you started. It happens, but reparing a motherboard does not take 'hours'. You put in the electrolytics, if it does not work, take them out and throw the board in the parts bin. Have you ever noticed the name of this newsgroup? --- Met vriendelijke groet, Maarten Bakker. |
#19
|
|||
|
|||
|
#20
|
|||
|
|||
Franc Zabkar wrote:
On 22 Jan 2005 18:07:10 -0800, put finger to keyboard and composed: Why not fix it? The replacement cost of a motherboard that will take a cpu and memory from a couple of years ago is what, $45 for a good one and it will be upgradeable to the newer and faster cpu come upgrade time. Then there is the opportunity cost of the time involved. If it takes one hour to replace all the capacitors on the board, and the board does wind up being good, how much was that one hour worth? Nobody has factored in the cost of installing the software for the new motherboard, not to mention possible additional compatibility issues. I did, actually. For example, those motherboards with onboard sound, video, modem, and LAN may need some work before all the drivers are functional. IME, mucking about with S/W is much more problematic and time consuming than changing a few caps. - Franc Zabkar -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#21
|
|||
|
|||
wrote:
wrote: It's no easy task to replace all the caps on a multi-layer board with plated through holes. You are likely to end up with a dead board. Try fault tracing on that one. Replacing is easy. Fault finding not. Replace them using a soldering iron of _sufficient_ power, though. If after replacing it still doesn't work? Bad luck, consider a new board. --- Met vriendelijke groet, Maarten Bakker. I think it can be difficult. Nonetheless, it's doable, and you can also hire somebody with the proper tools to do it and still come away with a lower bill than for a new MB. When my Epox motherboard exhibited the problem, I sent it back to them and they replaced the capacitors (at least the ones that were obviously bad, but that's another story) for about 20 bucks. Even with shipping that's less than a new MB would cost. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#22
|
|||
|
|||
Al wrote: In trying to figure out why this atx pc won't start, I carefully looked at the motherboard. Some of the blue 'can' capacitors are straight across the top, with the X shape. But others are bulged up. It's a sign of impending doom, and if left unfixed may eventually cause failure of the components connected to them, like the toroid coils and MOSFETs. I had one MOSFET heat up enough to turn from black to light tan, and after replacing the caps and installing a new MOSFET, it ran at over 100C, even with a big copper heatsink, because the chip driving it had been wrecked, too. Probably the safest way to replace caps without using special equipment is by cutting them off on top -- right through their cans, so that the pins can be unsoldered individually. But I learned that multilayer boards need a lot more soldering iron power than normal, and even 40W may not melt the solder right away while 50W will. I used 2mm copper desoldering braid to clean out the holes because I didn't have very good luck with solder suckers. I'd replace even the caps that still look normal because recently one of my Antec PSUs had one cap bulge while the others were not only still flat but also tested good with an ESR meter. Yet one of those "good" caps bulged a week later and showed high ESR. |
#23
|
|||
|
|||
On Sun, 23 Jan 2005 23:46:16 GMT, CJT put
finger to keyboard and composed: Franc Zabkar wrote: On 22 Jan 2005 18:07:10 -0800, put finger to keyboard and composed: Why not fix it? The replacement cost of a motherboard that will take a cpu and memory from a couple of years ago is what, $45 for a good one and it will be upgradeable to the newer and faster cpu come upgrade time. Then there is the opportunity cost of the time involved. If it takes one hour to replace all the capacitors on the board, and the board does wind up being good, how much was that one hour worth? Nobody has factored in the cost of installing the software for the new motherboard, not to mention possible additional compatibility issues. I did, actually. Yes, you did. Sorry. For example, those motherboards with onboard sound, video, modem, and LAN may need some work before all the drivers are functional. IME, mucking about with S/W is much more problematic and time consuming than changing a few caps. - Franc Zabkar - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
#24
|
|||
|
|||
|
#25
|
|||
|
|||
It's no easy task to replace all the caps on a multi-layer board with plated through holes. You are likely to end up with a dead board. Try fault tracing on that one. I haven't found it to be particularly hard, just use a 140W Weller soldering gun, you need a LOT of heat but if you have the right tools it's pretty easy. |
#26
|
|||
|
|||
"Al" wrote in message . .. In article .com, says... But I learned that multilayer boards need a lot more soldering iron power than normal, and even 40W may not melt the solder right away while 50W will. I have an old Wen 199 gun. It doesn't state any wattage rating. Will that do, or is it too hot? Try it, it's really hard to overheat the ground and power plains on those boards. |
#27
|
|||
|
|||
Al wrote: In article .com, says... But I learned that multilayer boards need a lot more soldering iron power than normal, and even 40W may not melt the solder right away while 50W will. I have an old Wen 199 gun. It doesn't state any wattage rating. Will that do, or is it too hot? I've never used a soldering gun, but I've read that a gun normally has to be rated for 2-3 times as much power as an iron for the same amount of heat. |
#28
|
|||
|
|||
JURB6006 wrote:
The other thing to consider is if it's running XP it uwill not/u migrate to a new mobo. Whilst it's not something I'd recommend, it most definitely *will*, and I've done it countless times. Same method as 98, just remove the DM tree, change the mobo and reboot. I've had no issues doing this across different chipsets and different CPUs, even across different HDDs. Of course if the machine will not currently boot into XP, then it will need a repair installation after changing the mobo. Lee -- Email address is valid, but is unlikely to be read. |
#29
|
|||
|
|||
CJT wrote:
I did, actually. Maybe you miscalculated something. Btw, a chopper in a TV is _not_ a motorcycle, allthough it does have something to do with dutycycles most of the time. --- Met vriendelijke groet, Maarten Bakker. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
How do shorted electrolyic capacitors measure up? | Electronics Repair | |||
A/C fan motor capacitors | Home Repair | |||
FS: Lots of 500: 50V 22uF Electrolytic Capacitors :: $ 27 SHIPPED | Electronics | |||
FS: Lots of 500: 50V 22uF Electrolytic Capacitors :: $ 27 SHIPPED | Electronics Repair | |||
Identifying non-electrolytic capacitors? | Electronics Repair |