Adam wrote:
So my questions are: Could the problem be those two slightly bulging
capacitors? If so, would I probably be able to replace them with just
an ordinary soldering iron? Could I try to reassemble the original
power supply and return the new one for a refund, or is that something
for experts only?
Thanks, everybody, for replying so soon! Here are my replies to
everybody in one message, otherwise I'd have to repeat a lot of things.
I'll emphasize that this would be my second computer -- there's nothing
wrong with my primary one, I just happened to acquire most of the parts
for a second system, even though I don't have any need for another one,
and figured it might be fun to play with it.
It's a FlexATX motherboard, 9" wide, 7.5" deep, with a 1.1 GHz
"Coppermine 128" Celeron. Bottom-end desktop from 2001. I haven't yet
seen the other side of the motherboard, but these look like everyday
cylindrical electrolytic capacitors (not surface mount), so I guess I
might be able to remove and replace them if I can find replacements at
RadioShack. I counted a total of 16 electrolytic caps on the
motherboard (two bulgy and 14 that look okay), but I really don't think
I'm capable of replacing 16 caps without wrecking the motherboard. Two,
maybe, but not 16. When I added a reset button to my primary system, it
took me three switches to get one to survive my soldering.
Phil M Perry wrote:
3) No, it would be unethical (at best) to return the power supply for
a refund, after it's been used AND POSSIBLY DAMAGED by the short. Keep
it as a spare or trade/sell it (after confirming that it's still good).
Okay, agreed. I just wish I hadn't spent the money on an unnecessary
power supply.
[email protected] wrote:
I had a friend who's computer was shutting down prematurely ( < 30s after power
on). I initially assumed overheating, but everything was within range. Then
replaced the power supply with no success. Examining the capacitors, I found 2
were bulgy. Swapping motherboards fixed it.
Sounds almost like my system. However, I don't want to put much money
into replacing a motherboard from 2001.
In both of these cases I was dealing with primary PCs.... wasn't going to mess
around repairing the motherboard myself.
This will be a secondary system, not much to lose if I mess it up.
You could try to replace the busted
capacitors yourself, but know that the lot of them on the board are likely of
the same bad batch, and will all need replacing to prevent the same problem
again down the road.
Now that is a depressing thought, as successfully replacing 16
capacitors will be costly and probably beyond my ability.
Clyde C Cottingham wrote:
What processor[s] are/is in the mb.
What form factor is the mb.
I have a ton of mbs/boxes around here that I would be happy to give away though
rather primitive.
clyde
Thank you very much, Clyde! Motherboard specs are in the second
paragraph at the top. If I can't replace the capacitors and you happen
to have an older motherboard or box /that you have absolutely no use
for/, I'd appreciate one of the ones you have. As I mentioned, this
would be a second, superfluous system so I wouldn't want to take away
what could be a first system for some computerless person.
Frank D. wrote:
This model of motherboard is known for having capacitor problems, so
I then looked at the motherboard more closely and discovered that two
adjacent electrolytic capacitors on it were bulging a little on top.
IIRC they're all supposed to be flat on top, like all the other
electrolytics there.
That's correct, the cap will bow and pop out all the electrolytic goo
if you beat it up enough (voltage rating not much above the
applications working voltage, temperature too high, old age, polarity
reversals, etc). It's the weak point in the capacitor on purpose and
by design. The top should absolutely be flat.
In that case, I definitely have two bad capacitors on the motherboard,
at least.
So my questions are: Could the problem be those two slightly bulging
capacitors? If so, would I probably be able to replace them with
just an ordinary soldering iron? Could I try to reassemble the
original power supply and return the new one for a refund, or is that
something for experts only?
It could be the capacitors. As Dr. House might advise you, the best
way to diagnose is to treat - and it's only a few cents worth of caps
(DigiKey).. or a couple bucks at most, if you go to RadioShack.
I'd go with RadioShack, since just ordering two capacitors from DigiKey
probably would come to just as much.
If you get some sort of enjoyment out of trying - or at least from
trying and having there be a chance that your effort will bear you a
working computer. If you wanted to try, you probably could do it with
an ordinary iron. Are they through-hole design (ie mount from the top,
legs go through the PCB and exit at the bottom, and have solder pads
on the bottom)? Solder pads on top and no vias? Either way if you're
careful you should be fine even with a cheap 15-30w iron. Just be
careful, apply heat for as short a duration as possible and don't drag
solder across the board.. :)
I haven't seen the bottom of the motherboard yet, but so far it looks
like the legs go through the PCB and are soldered on the other side...
so repair might be possible.
What did you disassemble in the power supply? Just removed the PCB
from the case? Go ahead and slap it back together if that's all you did.
Yep, just unscrewed everything, didn't cut any wires or remove
components. If I can just remember how it all fit together, and find
all the screws...
Actually yeah, if you need a board I have an MSI that's still good.
Has a nice copper ThermalTake cooler, Socket A, XP 2100+
Thoroughbred-B CPU, 1GB of PC-2700. You'd need a video card, but it
has onboard 100mbit LAN (VIA Rhine) and AC '97 sound. KT400A/VT8235
chipset IIRC, everything works under Linux at least. Be something to
play with if your repair doesn't go well *shrug* Let me know. I
probably have a VIA chip based SATA card if you needed one, too.
Thanks very much for the offer! I described the existing motherboard in
the second paragraph at the top. It has an IDE HD and CD-RW drive. I
just bought a low-profile PCI (not PCI-E) video card for it (because I
managed to wreck the onboard VGA connector), and have a few older
full-height PCI video cards around here as well.
Phil M Perry wrote:
Yeah, a few years back, this was in the news. Some component
manufacturer in Taiwan stole the "recipe" for the electrolyte from a
manufacturer in Japan. Trouble was, they didn't get the full recipe,
and were missing some key ingredient, which led to caps with very
short lifetimes. Electrolytics are one place where you just can't
skimp. Buy quality, and consider replacing ALL of them at the same
time. Even quality electrolytics can fail with age.
As mentioned, I don't think my hardware skills would stretch to
successfully replacing 16 capacitors... and I'm not sure it would be
worth it, for a 2001 bottom-end motherboard.
http://www.siliconchip.com.au/cms/A_30328/article.html
Thanks! That's about the time frame, since this motherboard is from
2001, and some other web sites mention Gateway as one of the affected
brands. However, it's been in use since then, and was working
adequately until last week. And the bulgy capacitors are /not/ the four
closest to the power connector (which look okay), but two slightly
smaller ones next to the RAM.
Again, thanks very much, everybody!
Adam
_______________________________________________
Mid-Hudson Valley Linux Users Group http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug
Upcoming Meetings (6pm - 8pm) MHVLS Auditorium
Jul 1 - Linux High Performance Computing
Aug 5 - TBD
Sept 2 - Linux and HDTV
