"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 ?

Arfa