Re: Hardware Question about RAM and Capacitors
On 12/12/2013 1:11 PM, Goren Buckwalk wrote:
...
> I have a system with two AMD Athlon 2400 MP processors and the
> motherboard has 4 slots for RAM.
That makes this board ~10 years old.
...
> About a month ago, I found the box crashed again and beeping on
> reboot, so going through the same elimination process found only the
> stick in the first slot would work. It seemed odd two sticks could go
> bad at the same time, so I tried them in that first slot and both
> worked. I tried adding some back and no matter the combination except
> for one single stick, always got a beep-fest. So I think all the RAM
> is good, but the last three slots are bad (or maybe just the 2nd is
> bad, and then the 3rd and 4th can't work without the 2nd??).
DIMM sockets don't fail. What fails is the power circuit supplying
voltage/current to the sockets.
> Looking closer I see three capacitors on the board (nearer to the
> CPUS than the ram slots) have a rusty looking coating on the top. One
> is worse looking than the other two (eh?), the two have some part of
> their tops that still look shiny silver. I've heard of capacitors
> going bad on motherboards, but never saw any. Is this rust a sign of
> failure and could their failure be the cause of the RAM slot
> problems?
Possibly. If you look at the PCB below the caps you'll see a colored
residue there as well (gravity). The caps get old, get hot, and the
aluminum casing separates. When this happens the oil spills out and the
cap is done/dead. This assumes a horizontal case. If the case is
vertical then gravity will pull the oil along the bottom edge of the cap
cylinder wall and pool there before drying. It may drip before drying
as well, so look at components nearby "underneath" the split caps.
Most mobo manufacturers switched about 5-6 years ago to using all solid
caps, no more oil/film parts. These have a much longer lifespan.
> Other than the lockups/memory beeping I've never really seen any
> issues with this system (did replace bad drive once or twice). It has
> boinc/seti/asteroids, webserver(s) and other stuff running (except
> when running BOINC its not heavily stressed but generally is doing
> _some_ work pretty much all the time).
>
> Are three rusty capacitors and 3 bad slots just a coincidence?
> Thanks.
Probably not coincidence. But keep in mind other components may have
failed as well. You could try recapping the board using your soldering
skills and one of these kits, or purchase individual caps for your
board: http://www.badcaps.net/pages.php?vid=21
But given the cost of $25-30 and your time, the fact that recapping may
not be a complete fix, and the gear is 10 years old, you may be better
off buying new guts. This seems to currently be the least expensive
Newegg AMD based combo:
$ 37 http://www.newegg.com/Product/Product.aspx?Item=N82E16813138376
$ 43 http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888
$ 26 http://www.newegg.com/Product/Product.aspx?Item=N82E16820231150
$106 Mobo, CPU, two DIMMs
Even with a single core at 2800 MHz clock the Sempron will run circles
around your twin MPs at 2x 2000 MHz clock, due to the 1 MB L2 cache (vs
256KB), the integrated memory controller, and dual channel DDR3-1333.
The Athlon MP 2400+ Socket A bus throughput is 2.1 GB/s or roughly 1.05
GB/s per CPU. This Sempron combo? 21 GB/s, 10x faster.
--
Stan
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