dave wrote:
> Nope, no timetable. I have two 8RDA+ systems and both have had the
> bulging, spewing, bad caps problem. One began to not boot and I
> replaced the caps to repair it. The other to this day is working fine
> with bad caps. My theory is much of it depends on the quality of the
> power supply. In other words, even if a motherboard has bad caps it may
> still function fine if the power supply has very well regulated outputs.
>
> DaveL
But the caps are used in places not directly connected to the PSU.
The caps on the output side of Vcore, are operating at the Vcore
voltage, in the neighborhood of 1.5V or so. So if those caps
malfunction, even the most manly power supply will not help them.
In some places on the motherboard, caps are used in a group. Each
cap carries some of the ripple current, which is the function of
a bypass cap. When one cap begins to bulge and no longer functions
correctly, the load is transferred to the good ones. Which can
accelerate their demise. So you may see some "correlation" in the
failure of caps, especially if they are carrying a heavy load.
And the caps can be replaced, but a repair person will likely
ask more for the work, than the replacement cost of the motherboard.
When cheap motherboards for other sockets are available at $50, you
cannot get much repair work done for $50. Only a dedicated hobbyist,
willing to do the work for free, plus someone paying for a handful
of caps, will be able to compete at the $50 level, and the
hobbyist will go hungry if he/she does too many of them.
I don't know anything about the person running this site. I got here
by entering the URL of another site that used to do repairs. At least
there is some info here, on how to do the repairs yourself, if you
are so inclined.
http://www.badcaps.net/tips/rem/
There is much lore in the selection of capacitors, and it is
surprisingly difficult to get your hands on some good ones. For
example, I can search down the part numbers of good ones, on
a capacitor manufacturer's web site, but not be able to find
them anywhere for sale. (Digikey, Mouser, and Newark are potential
places to get them.)
One other thing - the rating printed on the plastic sleeve (the
capacitance), is seldom the most important parameter. There are
other parameters, which are listed in the catalog for such parts,
that is part of the selection process. So when someone says
"use a bigger one with more microfarads", that is seldom correct
advice, at least on a motherboard. If selecting capacitors for
yourself, without help from sites like badcaps.net, you can get
some advice by downloading the datasheet for the switching regulator
chip, as they usually explain some of the tradeoffs between
the parameters like ESL, ESR, ripple current etc.
Paul
>
>
> "Lee M." <lmacmil.RemoveThis@forget_it.com> wrote in message
> news:f9ydnQmgeu3WZ1jYnZ2dnUVZ_vShnZ2d@comcast.com...
>> Just bought my kid's 8RDA+ and I see several of the caps are bulging
>> with some brownish crud on them. He hadn't said he had any problems,
>> just wanted a faster system. Once the caps start bulging, is there
>> any timetable before I might start seeing problems? My 6 yr old 8KHA+
>> does not have bulging caps. The 8RDA+ will be in a backup computer,
>> not my main machine. I will probably only see 3-4 hrs a week of on time.
>>
>>
>>
> >> Stay informed about: 8RDA+ with failing caps