On Sat, 12 Jun 2004 06:13:51 GMT, "Noozer" <postmaster@127.0.0.1> wrote:
>Just had one of my PC's fail. When the PS was switched on (back power
>switch) the machine would blip on and off and stay off.
>
>The board is an ECS v3.1 K7VTA3 board with RAID (specs here:
>http://www.ecsusa.com/products/k7vta3_3.html )
>
>Looking at the mainboard, the three capacitors at the rear of the mainboard
>by the regulators were all swollen. These are 6.3v 3300uf capacitors by
>"OST".
>
>I got the board running again by pulling all three caps and installing a
>single 10v 1500uf cap. DEFINATELY not the best solution, but it's the
>closest match I could make and I need the machine running. PSU has been
>swapped as I *THINK* that the original PSU may be straining the mainboards.
Since you need machine running, immedately source more caps, or replace
board, and underclock it as much as possible.
If you can follow the regulation circuit, note where in the circuit the
caps appear. Power supply problem would typically cause failure of those
on the high side of the circuit. That is, measured they'd be at (slightly
less than) 5V read by a meter. Overclocking would typically cause failure
of caps on low side, voltage of cpu vcore.
>
>Does anyone know if this mainboard has a history of failing caps? Is there a
>way to tell if a PSU is out of spec enough to be damaging the caps?
Ost caps are not among the most commonly mentioned brands that were
subject to fail in past years' boards, but IF they are the problem you'd
be looking at replacing most if not all of them... from the picture at
link you provided that looks like 11 caps left of cpu, a few more around
memory banks and a couple above agp slot, though i can't see well enough
if all of those are same make and model.
You could take a multimeter, probes, to the back side of the ATX connector
where the leads enter and measure running voltage, but that will not be
sufficient to measure ripple. It's possible you have a power supply
design problem and/or component failure or inadequate capacity. You might
assess it's true capacity compared to that needed by the system, and
(after unplugging it for a few minutes) open it and inspect it,
particularly the caps nearer the wiring harness exiting the casing.
If the power supply is an overrated generic, the best course of action
would be to replace it. Since you don't have the spare capacitors and
there appear to be so many of same type, it might also be best to just
replace whole motherboard. At the very least, get more caps onto the
board, a single 150j0uF cap is not going to take the place of 3 3300uF for
very long, particularly if the power supply is the problem rather than the
caps themselves.
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