Yet another bulging-capacitors replacement

[whit3rd]

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.

 

[Meat Plow]

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



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Arfa Daily]

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.08.26.21.04.20@hahahahahahahah.nutz.I.am...

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

 

[Jeff Liebermann]

On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
<http://www.frostytech.com/articleview.cfm?articleID=2273>
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[N_Cook]

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:jh3e761hp6mg3b0sb1h6stsdsq19g2mk0m@4ax.com...

On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing
of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on minimal.
Having to decide this week whether to spend out on 6 MJ series TO3 devices
in an old Carver amp failed due to one of the driver TO3 being pushed
through a heap of white grease , so grease on pins getting inside the TO3
socket housing , so insulating partially and eventually burning up the pin .

 

[Archon]

On 8/26/2010 8:27 PM, Arfa Daily wrote:

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.08.26.21.04.20@hahahahahahahah.nutz.I.am...
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
On games PC's i've gone to water cooling, blissfully quiet (apart from

the fishtank type noise!), CPU and GPU a few degrees above room temp
even at full load. Never go back to jet engine graphics card fans.
JC

 

[Meat Plow]

On Fri, 27 Aug 2010 01:27:14 +0100, Arfa Daily wrote:

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.08.26.21.04.20@hahahahahahahah.nutz.I.am...
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%.





--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Meat Plow]

On Fri, 27 Aug 2010 08:29:01 +0100, N_Cook wrote:

Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on
minimal. Having to decide this week whether to spend out on 6 MJ series
TO3 devices in an old Carver amp failed due to one of the driver TO3
being pushed through a heap of white grease , so grease on pins getting
inside the TO3 socket housing , so insulating partially and eventually
burning up the pin .

I've seen pads used in a lot of high power amps. Soundcraftsmen, BGW,
Carver, Peavey, Crown all used them at some time or another. If the
devices are torqued down properly I don't have a problem with them. You
are talking about the rubberized pads with embedded compound right?



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Jeff Liebermann]

On Fri, 27 Aug 2010 08:29:01 +0100, "N_Cook" <diverse@tcp.co.uk>
wrote:

Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on minimal.

Do the math. Silicon impregnated rubber TO-3 pads have a thermal
resistance of about 0.4K/watt. 0.0002" Mica, with silicon grease
smeared on both sides is about 0.6K/watt. Depending on your total
power dissipation, that's hardly any difference. However, if your
heat sink is undersized, buried inside a cabinet, or located in a
place where there's no air flow, it might make a difference.

<http://www.wakefield.com/LinkClick.aspx?fileticket=1ULQQwz8xmU%3d&tabid=64>
See Page 6-8. The example shown is for a TO-3 packaged device.

Having to decide this week whether to spend out on 6 MJ series TO3 devices
in an old Carver amp failed due to one of the driver TO3 being pushed
through a heap of white grease , so grease on pins getting inside the TO3
socket housing , so insulating partially and eventually burning up the pin .

Keep it stock. However, if this is a push-pull type of amp, where the
thermal balance of the xsistors has an effect on the bias point,
crossover distortion, and possibly linearity, I would make sure that
whatever you do to one side, the same gets done to the other.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Arfa Daily]

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:jh3e761hp6mg3b0sb1h6stsdsq19g2mk0m@4ax.com...

On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing
of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann jeffl@cruzio.com

Thanks for the insights Jeff. All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

Arfa

 

[Arfa Daily]

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.08.27.13.09.02@hahahahahahahah.nutz.I.am...

On Fri, 27 Aug 2010 01:27:14 +0100, Arfa Daily wrote:

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.08.26.21.04.20@hahahahahahahah.nutz.I.am...
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

 

[Jim Yanik]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:dgZdo.79946$Pa3.38201@hurricane:

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:jh3e761hp6mg3b0sb1h6stsdsq19g2mk0m@4ax.com...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

Anyone
else got any constructive comments on the subject of thermal
interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop,
causing some things to be more critical. In the process of getting
it to work, I learned a few things.

1. The less silicon grease used, the better. The idea behind
silicon grease is to fill in the gaps, scratches, and gouges in the
power transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top
center of the CPU, will cause the substrate to bend, and eventually
break. I have some ideas, but nothing that can be retrofitted to an
existing motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink
face, use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann jeffl@cruzio.com


Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa

what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video drive
(or LCD backlight) circuitry.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[Jeff Liebermann]

On Sat, 28 Aug 2010 02:04:07 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

Thanks for the insights Jeff.

There was quite a bit of "Learn By Destroying(tm)" involved. Measuring
flatness and thermal resistance were a major exercise, but settled all
kinds of lab arguments.

Incidentally, you might be interested in how Arctic Silver works.
<http://www.arcticsilver.com/products.htm>
<http://www.arcticsilver.com/msds.htm>
Silver has a much higher thermal conductivity (410 W/m*K) as compared
to zinc oxide (21 W/m*K) and aluminum oxide (30 W/m*K) which is what's
in common thermal compound.
<http://en.wikipedia.org/wiki/List_of_thermal_conductivities>
However, if your shove an ohms-guesser into a puddle of Arctic Silver,
it's not conductive. That's because the particles of silver are so
far and few, that the bulk of the solution is polyolester or mineral
oil, which insulates the particles from each other, preventing mutual
contact. However, if you tear apart a CPU/heatsink that's been used
for a while, you'll notice that the Arctic Silver is a thick and dense
paste which is conductive. What has happened is that the polyol ester
mixture has evaporated sufficiently to provide contact between
particles. Since thermal conductivity is best through the silver
particles, the result is a superior thermal connection, with the
sliver particles filling the voids. You could do the same thing with
silver dust, but it would difficult to handle and apply. Meanwhile,
ordinary silicon grease does the same thing, but there's a difference.
The oil does not evaporate as easily, and the ceramic particles are
much larger and less compressible than the silver particles. Fewer
points of contact and lower thermal conductivity of ceramic, means a
worse thermal connection.

All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
<http://en.wikipedia.org/wiki/Alpha_21364>
which burned 155 watts. Itanium II came close with 130 watts (per
core). I had an Alpha CPU machine to play with for a while, which
would burn my hand from the hot air coming out the back.

If you have a power line wattmeter or a Kill-A-Watt meter, I think a
measurement would be helpful.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Arfa Daily]

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video drive
(or LCD backlight) circuitry.

--
Jim Yanik

Er no. There are no backlights. Or display processor. These are X-Box /
Playstation type boxes. Apart from some support circuitry in IC form - which
admittedly does gobble enough power to make it run hot enough that a degree
of heatsinking to the pcb shielding via thermal pads is required -
everything goes on in a pair of very large BGA processors, one of which is
the data processing engine, and the other of which is the graphics
processing engine. It is they which make use of the 12v, and they which
gobble the amps from it ...

The power supply does have other outputs, but these are all at very low
current availabilities, so will be for support logic and maybe some core
supplies for the two processors. Trust me when I say that the two big chips
is where all the power is going, and generating heat that needs shifting


Arfa

 

[Arfa Daily]

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:ebug76lk13plippid57h6q6vacu8ve4om9@4ax.com...

On Sat, 28 Aug 2010 02:04:07 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

Thanks for the insights Jeff.

There was quite a bit of "Learn By Destroying(tm)" involved. Measuring
flatness and thermal resistance were a major exercise, but settled all
kinds of lab arguments.

Incidentally, you might be interested in how Arctic Silver works.
http://www.arcticsilver.com/products.htm
http://www.arcticsilver.com/msds.htm
Silver has a much higher thermal conductivity (410 W/m*K) as compared
to zinc oxide (21 W/m*K) and aluminum oxide (30 W/m*K) which is what's
in common thermal compound.
http://en.wikipedia.org/wiki/List_of_thermal_conductivities
However, if your shove an ohms-guesser into a puddle of Arctic Silver,
it's not conductive. That's because the particles of silver are so
far and few, that the bulk of the solution is polyolester or mineral
oil, which insulates the particles from each other, preventing mutual
contact. However, if you tear apart a CPU/heatsink that's been used
for a while, you'll notice that the Arctic Silver is a thick and dense
paste which is conductive. What has happened is that the polyol ester
mixture has evaporated sufficiently to provide contact between
particles. Since thermal conductivity is best through the silver
particles, the result is a superior thermal connection, with the
sliver particles filling the voids. You could do the same thing with
silver dust, but it would difficult to handle and apply. Meanwhile,
ordinary silicon grease does the same thing, but there's a difference.
The oil does not evaporate as easily, and the ceramic particles are
much larger and less compressible than the silver particles. Fewer
points of contact and lower thermal conductivity of ceramic, means a
worse thermal connection.

All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced
to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core). I had an Alpha CPU machine to play with for a while, which
would burn my hand from the hot air coming out the back.

If you have a power line wattmeter or a Kill-A-Watt meter, I think a
measurement would be helpful.

--
Jeff Liebermann jeffl@cruzio.com

Again, more interesting stuff Jeff. As to the power consumption of these
chips, see my reply to Jim above. Also, it is split between two chips, it's
actually not quite as much as 300 watts, and will of course be an 'on
demand' thing, depending on how hard the chips are being asked to work by
the processing task that's happening at the time, so the 23 amps is only a
worst case potential input current. However, that said, these two chips do
produce *very* considerable heat even when idling to produce nothing more
than the splash screen.

Arfa

 

[Arfa Daily]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message news:...

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive
(or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box /
Playstation type boxes. Apart from some support circuitry in IC form -
which admittedly does gobble enough power to make it run hot enough that a
degree of heatsinking to the pcb shielding via thermal pads is required -
everything goes on in a pair of very large BGA processors, one of which is
the data processing engine, and the other of which is the graphics
processing engine. It is they which make use of the 12v, and they which
gobble the amps from it ...

The power supply does have other outputs, but these are all at very low
current availabilities, so will be for support logic and maybe some core
supplies for the two processors. Trust me when I say that the two big
chips is where all the power is going, and generating heat that needs
shifting

Arfa

 

[Jim Yanik]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:O24eo.36157$r24.2988@hurricane:

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty
three amps ...

Almost all of this is potentially going into these two processors,
so not far off 300 watts between them. No mean task shifting the
heat off them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box
/ Playstation type boxes. Apart from some support circuitry in IC form
- which admittedly does gobble enough power to make it run hot enough
that a degree of heatsinking to the pcb shielding via thermal pads is
required - everything goes on in a pair of very large BGA processors,
one of which is the data processing engine, and the other of which is
the graphics processing engine. It is they which make use of the 12v,
and they which gobble the amps from it ...

The power supply does have other outputs, but these are all at very
low current availabilities, so will be for support logic and maybe
some core supplies for the two processors. Trust me when I say that
the two big chips is where all the power is going, and generating heat
that needs shifting


Arfa

Odd that BGA processors are using 12V instead of logic level voltages.

I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Jim Yanik
jyanik
at
localnet
dot com

 

[Michael A. Terrell]

Jim Yanik wrote:

Odd that BGA processors are using 12V instead of logic level voltages.

Then they would need around 100A at 3.3 volts. The voltage drop
would be a big problem. I'm sure there is a DC to DC converter near the
chip, like used on computer motherboards.

I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

 

[Meat Plow]

On Fri, 27 Aug 2010 21:18:05 -0500, Jim Yanik wrote:

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:dgZdo.79946$Pa3.38201@hurricane:



"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:jh3e761hp6mg3b0sb1h6stsdsq19g2mk0m@4ax.com...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

Anyone
else got any constructive comments on the subject of thermal
interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273> Note the
comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann jeffl@cruzio.com


Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V? ISTR that today's uPs run
mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

Most run at 12. The core at 1.6. Both AMD and Intel boards have a 4 pin
Molex plug near the CPU for direct 12v from the PSU.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Arfa Daily]

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns9DE25B60366AAjyaniklocalnetcom@216.168.3.44...

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:O24eo.36157$r24.2988@hurricane:

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty
three amps ...

Almost all of this is potentially going into these two processors,
so not far off 300 watts between them. No mean task shifting the
heat off them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box
/ Playstation type boxes. Apart from some support circuitry in IC form
- which admittedly does gobble enough power to make it run hot enough
that a degree of heatsinking to the pcb shielding via thermal pads is
required - everything goes on in a pair of very large BGA processors,
one of which is the data processing engine, and the other of which is
the graphics processing engine. It is they which make use of the 12v,
and they which gobble the amps from it ...

The power supply does have other outputs, but these are all at very
low current availabilities, so will be for support logic and maybe
some core supplies for the two processors. Trust me when I say that
the two big chips is where all the power is going, and generating heat
that needs shifting


Arfa



Odd that BGA processors are using 12V instead of logic level voltages.

I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Jim Yanik

Yes, I was amazed when I read the PSU specs. One of the versions is actually
specced 12v at 32 amps !! The PSU plugs directly onto the board via a pair
of brass pins as thick as those on a power cord for a kettle. The heat is
removed via a pair of flat plates that are connected to a network of sealed
copper pipes, a bit like you see on some Technics amps. I've no idea what is
inside those pipes. This whole assembly is cooled by a centrifugal fan that
idles at a very low speed. The heatsinks have to get up to blisteringly hot
before the processor thinks that it might be a good idea to ramp up the
speed of the fan a bit. I guess they have done this to try and keep the
thing quiet, but personally, I think it is a really poor bit of design. I am
looking at ways to make the fan idle faster, without compromising the auto
ramp up beyond that, when the processor deems it necessary, but
unfortunately, it's not quite as easy as a simple 'analogue OR' function,
because the fan is controlled digitally. It is supplied with a constant 12v,
but a third wire has a PWM signal placed on it by the CPU, and the fan's
internal electronics respond to that to control the speed.

Yes, it was the Cray. It had a central octagonal bus backplane as I recall.
The met office here in the UK used to use one for weather data number
crunching, but I think it has been replaced now.

Arfa