"Meat Plow" wrote in message
news
On Fri, 27 Aug 2010 01:27:14 +0100, Arfa Daily wrote:

"Meat Plow" wrote in message
news
On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the
capacitors in the power supply, not on the logic board, that were
bulging and leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements
for the
nine low-V high-I filter capacitors in the power supply, in form
factors that would fit the cramped footprint of the originals. So, I
thought I'd relate the parts list here, in case anyone else has need
of such info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC
PSU and will be looking for some replacement caps. I like to keep a
spare and I need 650 with this new AMD 120 watt quad core PhenomII 3.2
ghz CPU and Asus M4A78E-T mobo. With Asus overclocking friendly special
settings I'm able to run it at 4.0 ghz for each core. Makes video
encoding on an application supporting multicore encoding really fly.
Not unusual to get over 350 frames/sec out of NTSC 740x480 avi's. I can
make a high quality 20 chapter DVD with all the bells and whistles in
about an hour. Used to take 24 hours on a 2ghz single core AMD




Just as a matter of interest Meat, what is your preferred brand and type
of heatsink goop when working with these very high power processors?
I've recently been working with some games machines that have two very
powerful processors on the board, and have been having some thermal
issues when using 'standard' white silicon grease on them, which appears
to be what the manufacturer used originally. I have today reassembled
one using some Arctic Silver compound instead, and it seems to be doing
a fine job. I have always resisted using this stuff, because it's so
messy, and so hard to remove unless you use the complementary cleaner,
but if it really is that much more effective, then I might be prepared
to live with these shortcomings. Anyone else got any constructive
comments on the subject of thermal interfacing of coolers to high power
chips ?


You answered your own question. The AMD heatsink / quad core PhenomII 955
Black Edition package comes with Artic Silver already applied. I'm using
an Antec server case that has a hole and tube in the side cover. The end
of the tube fits directly over the CPU heat sink so it draws air directly
from the outside. In back is a pair of 120mm fans controlled by the
mainboard. If the CPU temp goes up all three fans increase according to
the temp. Or you can set them to run at full speed all the time. The 650
watt PSU also has a temp sensing 120mm fan. So the box is really quiet
most of the time. But when rendering video and the CPU usage hovers
around 50% fan speed increases slightly. Video rendering with an
application that takes advantage of multi-core processors seem to use the
most CPU percentage. I've never seen it go over 50%. Most of the time it
doesn't go over 10%.


Yes, seems to be 'busy' video rendering that causes all the problems on the
machines I am working on. Q & D calcs show that at max chat, the two
processors are potentially using close to 300 watts of input power between
them, and the heat that this generates in them, takes some shifting ...

Arfa