Shorted Computer Power Supply
KenO
was turned on and the CPS blew.
The CPS is a ilssan model ISP 120SI from a eTower PC.
When I inspected the CPS components and PC board, found the fuse did
Not blow and only visible damage was a short section of burned wire of
one inductor coil. If you tell me how will post photos of the CPS for
your examination.
Searched the forum and found something similar. "computer power supply
shorted - no apparent cause of death"
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/41dcf3e558d25914/bc6a0fb184aa060d?hl=en&lnk=gst&q=blown+computer+power+supply#bc6a0fb184aa060d
What was recommended was
1. "Check for fusible resistors (usually only a couple of ohms,
designed to go open rapidly and with no visible effect)"
Question: If the damage is not visible is there any method of choosing
what resistors to check?
Also Is there any way to differentiate fusible resistors from standard
ones?
Searched for a schematic but so far have not found one.
Thanks
Ken
ne...@jecarter.us
With the supply connected to the motherboiard as well? If so, the
odds of having damaged other components connected to the power supply
are so high that the power supply is the least of your worries.
Spend a few dollars on a new power supply - DIY repairs are not
something a novice is likely to be successful with.
John
On Wed, 18 May 2011 13:27:54 -0700 (PDT), KenO <kenit...@yahoo.com>
wrote:
Jeff Liebermann
wrote:
>Searched for a schematic but so far have not found one.
ATX Power Supply Schematic
<http://www.google.com/search?q=atx+power+supply+schematic&hl=en&prmd=ivns&tbm=isch>
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS
KenO
Thanks for your link ATX Power Supply Schematic <http://
www.google.com/search?q=atx+power+supply+schematic&hl=en&prmd=...>
Could not find any schematic for ilssan model ISP 120SI
When I searched used
http://www.google.com/search?as_q=ilssan+atx+power+supply+schematic&hl=en&biw=1440&bih=706&tbm=isch&btnG=Google+Search&as_epq=&as_oq=&as_eq=&imgtype=&imgsz=&imgw=&imgh=&imgar=&as_filetype=&imgc=&as_sitesearch=&as_rights=&safe=images&as_st=y
but also found No ilssan schematics.
Ken
Jeff Liebermann
wrote:
>Thanks for your link ATX Power Supply Schematic <http://
I doubt if you're going to find the specific schematic for a Ilssan
whatever. Open the case, and identify the regulator chip. Then, dig
through the mess of schematics that Google finds and see if you can
find a similar schematic that uses the same chip. You won't get the
exact schematic but it will be close.
"Notes on the Troubleshooting and Repair of Small Switchmode Power
Supplies"
<http://repairfaq.ece.drexel.edu/sam/smpsfaq.htm>
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
larry moe 'n curly
KenO wrote:
> I tried to connect a hard drive while the [power supply] was turned on and [it] blew.
>
> When I inspected the [power supply] components and PC board, found the fuse did
> Not blow and only visible damage was a short section of burned wire of
> one inductor coil. If you tell me how will post photos of the [power supply] for
> your examination.
Try a photo posting place, like Flickr.com , PhotoBucket.com , or, if
you don't want to register with the site, try TinyPic.com or
ImageShack.us .
Really, really good FAQ about electronics repair: www.RepairFAQ.org
Unplug the AC power cord before opening the power supply, and don't
even test it unless its cover is fully installed (all screws
tightened).
I'm no expert, but I've never seen a fusible resistor inside a common
PC power supply, except maybe the large rectangular ceramic ones.
Fusible resistors are more common on motherboards, near the ports for
the keyboard, mouse, and USB, and on hard drives (usually next to a
zener to protect against overvoltage, and if it triggers, the fuse
associated with it pops). When regular resistors open up (higher than
rated resistance), they usually show burn marks or cracks, but fusible
resistors usually open up without showing damage.
The only coils that tend to burn in power supplies are those for the
automatic power factor correction (high voltage side) and the output
filters (low voltage side), and I think your problem is related to the
latter because those coils run hot, and those coils vary a lot in
size, depending not only on power ratings but also on the quality. If
the affected coil is in the low voltage section, maybe you can
separate its wires from one another in the burned area and coat them
with varnish. Do NOT do this if the coil handles high voltage.
Typically when a PC power supply fails and its fuse doesn't pop, the
problem is in the low voltage section, such as a shorted diode or
MOSFET or a worn electrolytic capacitor. Use only low-ESR capacitors
for replacement, preferrably of the same diameter (tight fit in
there). Any replacement diode or MOSFET has to be of the same type
(diode should be Schottky) and meet the same minimum ratings for amps,
volts, and watts. To remove anything attached to a heatsink, it's
usually necessary to unsolder everything, including the heatsink.
larry moe 'n curly
KenO wrote:
> Could not find any schematic for ilssan model ISP 120SI
Reepair.net/en or ElektroTanya.com may have something, but more likely
you'll have
to find the controller chips and rely on data sheets and applications
notes from the makers of those chips.
But generally, to fix an ATX power supply you just look for physical
damage, bad solder joints, and check
diodes and transistors with a meter.
Sylvia Else
I'm going to second, or is it third, or fourth, sentiments expressed by
others.
A power supply has safety issues with it. Do something wrong, and it
could burn down your house. How are you going to test it anyway? It
probably won't run without a load? Attach it to your motherboard? Could
be bye-bye MB.
Send it to the tip.
Sylvia.
Jeff Liebermann
<syl...@not.here.invalid> wrote:
>A power supply has safety issues with it. Do something wrong, and it
>could burn down your house. How are you going to test it anyway? It
>probably won't run without a load? Attach it to your motherboard? Could
>be bye-bye MB.
You mean like this?
<http://802.11junk.com/jeffl/crud/atx-blown.jpg>
It was fairly impressive when it went off in my face. Fortunately, I
was wearing glasses.
Sylvia Else
> On Fri, 20 May 2011 12:16:00 +1000, Sylvia Else
> <syl...@not.here.invalid> wrote:
>
>> A power supply has safety issues with it. Do something wrong, and it
>> could burn down your house. How are you going to test it anyway? It
>> probably won't run without a load? Attach it to your motherboard? Could
>> be bye-bye MB.
>
> You mean like this?
> <http://802.11junk.com/jeffl/crud/atx-blown.jpg>
> It was fairly impressive when it went off in my face. Fortunately, I
> was wearing glasses.
>
Yes, I've been glad to have been wearing safety glasses on occasion when
bits of power transistor have attempted to go into orbit (UPS repair).
Sylvia.
Jeff Liebermann
<syl...@not.here.invalid> wrote:
>On 20/05/2011 2:37 PM, Jeff Liebermann wrote:
>> On Fri, 20 May 2011 12:16:00 +1000, Sylvia Else
>> <syl...@not.here.invalid> wrote:
>>
>>> A power supply has safety issues with it. Do something wrong, and it
>>> could burn down your house. How are you going to test it anyway? It
>>> probably won't run without a load? Attach it to your motherboard? Could
>>> be bye-bye MB.
>>
>> You mean like this?
>> <http://802.11junk.com/jeffl/crud/atx-blown.jpg>
>> It was fairly impressive when it went off in my face. Fortunately, I
>> was wearing glasses.
>Yes, I've been glad to have been wearing safety glasses on occasion when
>bits of power transistor have attempted to go into orbit (UPS repair).
>Sylvia.
[Q] What's the difference between a battery and an explosive?
[A] Energy density.
Batteries
Lead Acid 150,000 Joules/Kg
Li-Ion 460,000 Joules/Kg
Lithium Thionyl Chloride 2,000,000 Joules/Kg
Explosives
TNT 4,700,000 Joules/Kg
We're getting there with batteries.
Smitty Two
Jeff Liebermann <je...@cruzio.com> wrote:
>
> [Q] What's the difference between a battery and an explosive?
> [A] Energy density.
> Batteries
> Lead Acid 150,000 Joules/Kg
> Li-Ion 460,000 Joules/Kg
> Lithium Thionyl Chloride 2,000,000 Joules/Kg
> Explosives
> TNT 4,700,000 Joules/Kg
> We're getting there with batteries.
Tesla should be working on a TNT powered automobile, then.
Jeff Liebermann
Sure. Black powder engines work:
<http://www.youtube.com/watch?v=oE29MJOnTdE>
However, I prefer reactor grade uranium fuel at 3.7*10^12 Joules/Kg to
power a UPS and vehicle.
The problem is that if you do find a way to rapidly discharge a
battery, it has enough energy to create an impressive explosion.
Power(watts) = Energy (Joules) / Time
The faster you extract the energy, the bigger the bang.
In the late 1960's, I successfully did that with a crow bar across a
55 gallon drum oil bath capacitor (fusible wire high voltage switch).
The crow bar didn't melt but the sound of the explosion shook the
building, set off alarms, deafend me for about an hour, and caused a
bulge in the can. With the latest Lithium-something battery
technologies, a major advantage is that one can extract large amounts
of current over a small interval. Most battery packs have circuits or
fuses to prevent this from happening, but if you're working with the
raw battery, the possibility of blowing something up is very real.
This might be one reason why UPS manufacturers are still using
lead-acid or AGM batteries, instead of going to Li-Ion mutations.
Of course, electric vehicle manufacturers have gone to some effort to
make their battery packs safe (SAE 2464, 2929). However, if you
bypass those safety features, you get a big bang.
<http://www.teslamotors.com/roadster/technology/battery>
KenO
Thanks for all your comments, links and photos.
Do not to confuse things so have started a new post "PC Power Supply
Recommendations?"
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/5d9c672c7593977e?hl=en#
Ken