Power supply EXPLOSION

On 21 Jul 2004 13:21:24 -0700, do_not_spam_me wrote:

"Peter Hucker" wrote in message news:opsbhnptolaiowgp@blue...

Ok, maybe watercooling the power supply was not a good idea.

It certainly kept the power transistors with the big heatsinks
cool, but what of the poor little diodes and a transformer,
which didn't get the airflow they expected?

Been working fine for a few weeks, then suddenly..... about
15 bangs, flashes, sparks etc flew out of it, as though I had
lit an entire box of fireworks under the desk. Strangely the
PC continued to run while this happened (for about 10 seconds,
at which point the PSU gave up and it went off. Fuses all
intact! Replaced the PSU, and the PC booted ok! Just one
drive of the mirror/stripe appeared to be blank/corrupted,
but it's autorebuilding it in the background.

http://80.229.155.158/temp/psufail

PSUFAIL1.JPG seems to show an LM339, a voltage comparator and not a
chip that normally handles high amounts of power. So I believe it
failed due to excessive voltage, not heat. That's not to say that the
high voltage wasn't caused by excessive heat somewhere else, and the
burned capacitor in PSUFAIL3.JPG could indicate that the main
transformeer got too hot and saturated, which can cause the current
through its coupling capacitor to increase greatly. I'm not sure what
PSUFAIL2.JPG is, but it looks like a transformer, and in PSUFAIL4.JPG,
it's possible that heavily-burned resistor R7 is either a load
resistor (some power supplies won't start without one, and excessive
voltage can burn it out) or part of a snubber (filter to eliminate
unwanted oscillations -- too much oscillation can burn it out).

In the process of testing the water cooling, did you put a temperature
probe on each of the power components? This can be risky because of
the high voltage, but there are probes with metal exposed only at the
tip, or for the more daring a dial thermometer (like a meat
thermometer) can be used if it's covered with a few layers of
heatshrink tubing. Transformer saturation is a big concern among
power supply designers, and heat makes them saturate at lower power
levels.

I checked the heatsink temperatures with my finger. Didn't think anything else would need it.




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On Wed, 21 Jul 2004 14:32:50 GMT, "rstlne"
wrote:

WaterCooling keeps the CPU and what ever else it's connected to cool..
So you dont have 45/50c air feeing the bottom of the heatsink..


Completely untrue.
Water cooling keeps ONLY the part under the water block cool.
"Almost" every other part of the system (which has heat needing
removed) will run hotter because there is the incorrect
assumption that water cooling reduces need for aux airflow.

Even water cooling a CPU is pointless except very extreme
environments or for max o'c. You still need a fan in roughly
same area to cool motherboard power regulators.

Water cooling CPU will not reduce temp of "what ever else it's
connected to" by any significant amount. The only way it could
do so would be by reducing heat 'sunk though the CPU pins to the
socket, but any other (relatively) temp-sensitive component is
far removed from that heat path. For example, you won't find any
electrolytic capacitors inside a socket well... not that they'd
be needed there, but there are multiple reasons.



That means that the PSU shouldnt have required tons of airflow.. It looks to
me like the psu just fail'd (short in transformer)..

Nope, it is true that PSU might've required "slightly" less
airflow but only because it's incoming air was a few degrees
cooler, since CPU heat was removed in a path other than drawing
that heat(ed air) up though PSU. Lower temp air though PSU means
lower volume is needed for same temp drop.

On Wed, 21 Jul 2004 16:30:16 GMT, "rstlne"
wrote:


"Peter Hucker" wrote in message
newspsbhqrth3aiowgp@blue...
That's one hell of a failure. I thought I was maybe overloading it, but
I'm using 200W peak, and it was a 300W supply.

Anyway I've sourced a fanless one for £120....



Yea, I have seen some nice new fanless ones out there in the market..
Tho to be honest I woulda probably been more tempted to just mount a couple
of NB coolers on the heatsinks inside the PSU itself (sure it could be
done).


Nope, there are ZERO nice new fanless ones.
The highest quality, best specs and longest lasting PSU are all
actively cooled. Effective passive cooling for a modern system
will require such large passive 'sinks that it won't come near
fitting into a PS/2 size allocation per the PSU casing or system
chassis. Best attempt is when huge fins stick out the back of
system, but even then there is no chance PSU will last as long
unless quite specifically made with different spec and type
components inside, which none have been due to greater cost.

On Wed, 21 Jul 2004 16:38:08 +0100, "Peter Hucker"
wrote:


Yea, I have seen some nice new fanless ones out there in the market..
Tho to be honest I woulda probably been more tempted to just mount a couple
of NB coolers on the heatsinks inside the PSU itself (sure it could be
done).

NB?

I DID mount coolers on the heatsinks. But I think more than that needed cooling.

Yes, the best solution would've been to simply leave the power
supply alone and install a lower flow fan, with rear grill
removed, then mod the REST of the system case to provide positive
pressurization that forces more air though the power supply.

Your conclusion was correct that there's more to cooling a power
supply than just keeping the regulators cool.

On Wed, 21 Jul 2004 19:25:57 +0100, "Peter Hucker"
wrote:


What do you mean no need for extra cooling? I was trying to use no fans!

Water cooling does not eliminate the need for fans, only reduces
amount of flow needed. Noise of water cooler eclipses that fan
flow noise difference to the extent that water cooling does not
make a system quieter except if compared to a very poorly
implemented air-cooling design. In other words, with same or
less time and less expense and risk the air-cooled solution is
quieter, more dependable, cheaper, safer. Whole world doesn't
use fans on a lark.

On Wed, 21 Jul 2004 22:06:24 GMT, kony wrote:

On Wed, 21 Jul 2004 16:30:16 GMT, "rstlne"
wrote:


"Peter Hucker" wrote in message
newspsbhqrth3aiowgp@blue...
That's one hell of a failure. I thought I was maybe overloading it, but
I'm using 200W peak, and it was a 300W supply.

Anyway I've sourced a fanless one for £120....



Yea, I have seen some nice new fanless ones out there in the market..
Tho to be honest I woulda probably been more tempted to just mount a couple
of NB coolers on the heatsinks inside the PSU itself (sure it could be
done).


Nope, there are ZERO nice new fanless ones.
The highest quality, best specs and longest lasting PSU are all
actively cooled. Effective passive cooling for a modern system
will require such large passive 'sinks that it won't come near
fitting into a PS/2 size allocation per the PSU casing or system
chassis. Best attempt is when huge fins stick out the back of
system, but even then there is no chance PSU will last as long
unless quite specifically made with different spec and type
components inside, which none have been due to greater cost.

Some I saw said 3 year warranty :-)

And the thermaltake (I think) ones have a thing out the back.




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On Wed, 21 Jul 2004 22:10:30 GMT, kony wrote:

On Wed, 21 Jul 2004 16:38:08 +0100, "Peter Hucker"
wrote:


Yea, I have seen some nice new fanless ones out there in the market..
Tho to be honest I woulda probably been more tempted to just mount a couple
of NB coolers on the heatsinks inside the PSU itself (sure it could be
done).

NB?

I DID mount coolers on the heatsinks. But I think more than that needed cooling.

Yes, the best solution would've been to simply leave the power
supply alone and install a lower flow fan, with rear grill
removed, then mod the REST of the system case to provide positive
pressurization that forces more air though the power supply.

Your conclusion was correct that there's more to cooling a power
supply than just keeping the regulators cool.

The rest of the system does not have fans! And even a low speed one in the PSU would be irritating.


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On Wed, 21 Jul 2004 22:14:53 GMT, kony wrote:

On Wed, 21 Jul 2004 19:25:57 +0100, "Peter Hucker"
wrote:


What do you mean no need for extra cooling? I was trying to use no fans!

Water cooling does not eliminate the need for fans, only reduces
amount of flow needed. Noise of water cooler eclipses that fan
flow noise difference to the extent that water cooling does not
make a system quieter except if compared to a very poorly
implemented air-cooling design. In other words, with same or
less time and less expense and risk the air-cooled solution is
quieter, more dependable, cheaper, safer. Whole world doesn't
use fans on a lark.

The water cooler is completely silent. And no I don't need fans.

The mac cube was designed without fans.


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"kony" wrote

Nope, there are ZERO nice new fanless ones.

Is this nice?

http://thermaltake.com/purepower/w00...fanlesspfc.htm

And this (not a psu) ?

http://thermaltake.com/coolers/cl-p0...fanless103.htm


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On Wed, 21 Jul 2004 23:28:32 +0100, "Peter Hucker"
wrote:


Your conclusion was correct that there's more to cooling a power
supply than just keeping the regulators cool.

The rest of the system does not have fans! And even a low speed one in the PSU would be irritating.

What is irritating about a fan you can't hear?

Comparing water cooling to worst-possible scenarios for fan
cooling is pointless, we could as easily compare to worst-case
scenarios with water pumps.

I did not claim you should use a high RPM fan. Personally, I
have no systems here nor that i've sold in past few years that
have even a single fan over 3000RPM and usually quite below that.
Once exception being video card fans, IF the warranty on the card
needs preserved, if that is more important to owner than noise
reduction of card then stock cooling solution must be retained.
First thing i do on cards I buy for my own use is replace stock
fan'sink after confirming card works properly, not defective/DOA.

Bottom line is that unless system is very _highly_ overclocked,
water cooling is the noiser way to cool a system. Pump creates
as much noise as very low RPM fan (like a panaflo or papst), then
either giant passive radiator is used or fan is still needed on
radiator, plus motherboard power regulation still needs airflow.
As incredible as it may seem, with a good 'normal' heatsink you
have same need for low RPM fan near that heatsink whether there
is a water block on CPU or not. You can operate without fan but
temps go up, in a region with a very clear temp vs lifespan
degradation (capacitors).