Im my search for motherboards I am only looking for the motherboard,
no RAM, or CPU. I have a CPU and RAM modules on the old board and tend
to use these on the next board.
Regarding my previous post and the question about motherbpoard testing.
I had in mind that perhaps there was some form of diagnostic tool that
could be plugged into the board. Grenn light fully functional; red light
faulty - something like that.
There was a video of production testing at one of the motherboard
companies, and their test setup was more complicated than that.
The closest thing to a test card, is a PCI Port 80 test card.
And it doesn't give much more information, than a beep test would.
Such a card is fine if you already own one, but potentially a
waste of money if you go looking to buy one.
There are loopback test devices, for testing communications ports.
So there are a few other small test tools of that type.
At the factory, there are two kinds ot testing: structural and functional.
Structural can be done with a bed-of-nails tester. It basically
verifies wires and signals. The bed-of-nails is less concerned
with what the motherboard is supposed to do. Where I worked, a lot of
our testing was done that way (boundary scan, continuity testing).
A motherboard manufacturer also gives the motherboard a two minute functional
check. Several removable assemblies are plugged into the motherboard,
and then it is tested. If you make three million motherboards a
month, you can't spend very long on each one. Of the two minutes,
some of the time is wasted just assembling and disassembling the
test setup.
It appears not to be the case. However, I
have read many posts where people talk of refurbished motherboards, this
does suggest that faulty boards have beeen repaired, hence faults must
have been identified.
A "tested" board, came from a working system. It's expensive to verify
the boards, if you're only charging $50 for each one. And if the companies
are in North America, the wage rate sees to it, that they can't afford
to do much work on each board.
A "refurbished" board, maybe they blew the dust off it. Or wiped it
with a damp cloth. (While boards can be washed in a thing that looks
like a dish washer, I doubt many small companies would bother. There
is also a risk of forcing dirt, underneath mechanical assemblies. You
have to install rubber dams on components that cannot take a washing.
You cover the Ethernet port, cover the CPU socket, and so on. Who is
going to go to that much trouble ?)
It would take an exceptional company, to have a repair
facility of any sort. Repairing boards in North America
simply costs too much. To get a Southbridge replaced here
(with 2.5D xray verification), costs about $1000. If you get someone
in Taiwan to do it, maybe $25, because they do so many of them, and
the staff are never idle. And nobody in a used motherboard
business, is going to shuttle products back and forth to a
country that can "do it for cheap". That would be a logistics
nightmare. Think of the paperwork at the borders.
If a board comes from one of the failure-prone Dells, then
you're looking for the words "re-capped", meaning capacitors
have been removed and new ones installed. The word "refurbished"
really is not specific enough, to conclude a board has been
re-capped, and a major source of unreliability, removed.
It's not like someone rebuilding a car alternator, and changing
the brushes and bearings. They more likely to just blow the
dust off, and put it in a box.
Many companies went through stuff like the following. Including one
motherboard firm that is no longer in business. This is
just a sampling of the cases. Some companies had a small number
of failures, while others had huge failure rates. And for those
motherboards, if you're looking for a spare one of the same
model, then you want confirmation it has been re-capped. If you want
someone to re-cap it for you, it costs $50 to $100 or so. (There
was a guy doing them for $50, but he got sick of it and quit.)
http://www.theregister.co.uk/2011/07/08/dell_optiplex_lawsuit_expanded/
For a motherboard with that kind of reliability problem,
simply looking at your own motherboard, and looking for
signs of leakage on the caps, may be enough to conclude there
was a risk the replacement boards would be just as bad.
If your board appears to be in good cosmetic shape, that's
a quick check maybe the replacement will be OK too.
I had a power supply here, an Antec (made by ChannelWell), and
the capacitors in that leaked, without the power being on.
That supply went bad, sitting in the box. For the capacitors with
bad internal chemistry, the capacitors can start to leak on their
own. They don't need to be stressed, to start the ball rolling.
http://en.wikipedia.org/wiki/Capacitor_plague
Reagarding the cooling fins on the card mentioned, I assume that
there must be a chip under the fins that requires cooling.
Yes
Up to a certain power level, you can use passive cooling, and
the fins are enough. Above that level, you need a fan blowing onto
the fins. With a typical fan, the performance of the heatsink
improves by around a factor of three. Even more is possible,
if heatpipes help distribute the heat into the arrays of fins.
The very best coolers, use heatpipes. A heatpipe can transfer
more heat flux, than an equivalent solid piece of copper.
This is an example of a video card cooler, where the heat from the
GPU, goes down those vapor-filled pipes, and then the heat
flows into the fins. The heatpipe allows a long thermal path,
while having a low thermal resistance, so you actually get
some benefit from the fins. If it weren't for the heatpipes on
this one, the outer fins would be cold to the touch. The heatpipe
ensures the heat, gets to the fins, and all the fin surface is
working. That grey material on the main heatsink body, aids
thermal conductivity to the top of the GPU chip. This thing
works better, than a solid aluminum (anodized) heatsink.
http://images17.newegg.com/is/image/newegg/35-186-054-Z03?$S300W$
HTH,
Paul
