Computer power failure

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newtechie

Hello all -

I'm posting this in 2 groups because I'm not sure where it should go. I
apologize in advance.

I'm having a power failure problem with my computer. It can be on for up to
30 min and then it'll power off by itself. I'll let it sit for about 5
minutes and when I go to turn it back on, nothing happens. I have to unplug
the power cord from the power supply and power it back on that way. I've
run a couple of system utilities program and they didn't detect any
problems. I've also checked the device manager and there are no yellow
question or exclamation marks and no red Xs. This has been happening for a
while now.

My computer specs are: Compaq Presario 6320 w/WinXP Home, AMD Athlon XP
2000+ processor (1.67ghz), 768mb ram, 60gb hard drive, cdrw and DVD rom
drives.

Does anyone know what could be causing this to happen and how do I fix it?
Could it be a faulty power supply? Please help. All replies and
suggestions will be appreciated.
 
Hi

You really need a bigger power supply than that. Something in region of
400+ would be better.
 
Your PSU is far too low for the system.... I'd suggest at least 350w,
however your problem seems to be caused by overheating rather than a faulty
PSU.... although it could be the fan in the PSU.

When it next comes on, check ALL fans in the PC, especially the one on the
CPU and the one in the PSU.
 
Hi Cari,

Thanks so much for your reply. I'm unsure why the fan is not coming on if
overheating is the cause.
The fan on the CPU sounds and looks normal. I might just have to buy
another power supply.

Newtechie
 
Cari said:
Your PSU is far too low for the system.... I'd suggest at least 350w,
however your problem seems to be caused by overheating rather than a faulty
PSU.... although it could be the fan in the PSU.

When it next comes on, check ALL fans in the PC, especially the one on the
CPU and the one in the PSU.
Click to expand...

Roger that...and don't skimp, get a GOOD one like a good Antech. PSUs DO
make a BIG difference. And put in as many case fans as your case can
accomodate.

--
Servo
"Long live the New Flesh!"
tservo100 at
ameritech dot net
Slow, fiery death to all spammers!!!
 
Fans fail in time. Sometimes it's the bearings, sometimes the motors.
Sometimes who knows!

I run a 550w PSU (3 hard drives and a DVD burner).......I think the
'smallest' PSU in all my desktop PCs is a 425w in my husband's PC. Mine
also has 3 case fans but I'm running a Prescott. Hubby's PC has 2 case
fans - he's an AthlonXP 2200+. My Server has the same specs as hubby's but
a 500w PSU.
 
Many brand name systems work just fine with a 250 watt
supply. 400 watts is well beyond what most everyone needs.
But then too many buy 'dumped' import supplies - making a
decision based only on price. The supply that is labeled 400
watts may only be 300 watts or less. So many computer
assemblers simply buy larger supplies rather than learn why
failures happen.

Discovering a power supply problem is quick and easy. Takes
but minutes and does not remove or change anything. No reason
to replace a supply unless it first is obviously a problem.
Procedure will probably take longer to read than it takes to
determine if power supply is really undersized:
"Computer doesnt start at all" in alt.comp.hardware on 10
Jan 2004 at
http://tinyurl.com/2t69q or
"I think my power supply is dead" in alt.comp.hardware on 5
Feb 2004 at http://www.tinyurl.com/2musa

In the meantime, what did system (event) logs report?

You symptoms can be created by a power supply controller
that is located on motherboard. Replacing the power supply
would not solve this problem. However heat is an excellent
diagnostic tool. Selectively heat motherboard sections and
other computer components with a hairdryer on high. That is a
normal operating temperature for all computer parts. A
properly working computer must work just fine in a room at
over 100 degree F. But intermittent components tend to fail
when heated. Heat is another diagnostic tool to locate a
defective part without wildly replacing anything.

Again, 400+ watt power supplies are well above what a
typical computer system requires. If power supply is too
small, that above procedure will identify the problem
immediately. And the event log says ...?
 
Hi Tom,

Thanks for your reply. I went and read over the postings from the links
suggested. I'm sorry but I did not understand any of it. I'm not too
familiar with power supplies and hardware of that nature.

There are no errors in event viewer. I've gone as far as dusting the fans
to no avail. I unhooked the power supply from the motherboard and replugged
it in. Still nothing. The computer has cut off twice in a 45 min. time
frame. The first 20 min and the second 10 min.

I'm beginning to rule out an overheating problem because the room the
computer is in is very cold and I took the side casing off to see if that
would help the inside breath a little. I noticed that the green power light
on the front of the computer remained on, but the power supply light on the
back wasn't. I let the computer sit for 15 min. in case overheating was a
factor and then tried to turn it back on but it did not power up. I again
had to unplug the cord from the back of the power supply, reconnect and then
power on the computer.

I don't know if the O/S could be causing this. Could it? Should I now
assume I have a faulty power supply? Any other suggestions?

Thanks,
Newtechie
 
Hi,

Sounds like a hardware problem. If you have to keep unplugging the power
supply directly from the wall socket, it could either be its going bad or
some part of the motherboard`s power integration system is bad. Best thing
to do is, either try using a different power supply from another computer
(if you have another to use), take the current one out and have it tested.

OS wouldn`t have anything to do with it not wanting to power on. Even when
there is no OS on the computer, you should just get the basic startup screen
showing the memory check, video version, choice of entering the bios setup,
etc.

You could also just take both the power supply and mother board to a
computer store that can do hardware testing. Also, if you are running a P4,
I hear it is recommended to have a power supply with at least 425 watts.

Jeff
 
System utilities usually will not catch a hardware problem. Some, such as
Motherboard Monitor 5 (now discontinued) do. But, if you have a successful
boot, the problem is presently not presenting itself so the program will not
detect anything as being wrong.

You have an intermittent hardware problem - maybe power supply, cooling
fans, CPU etc. If you don't have replacement parts that you can swap in,
take the computer to a "reputable" repair person.

--

Regards:

Richard Urban

aka Crusty (-: Old B@stard :-)
 
If that procedure to verify power supply integrity is too
complex, then you are reading too much into it. You take a
meter. You put meter leads on black wire and yellow wire
(where power supply connects to motherboard). Number
displayed on meter is recorded on paper. Repeat this for
orange wire, red wire, etc. When done, compare those recorded
numbers with numbers in chart. If numbers are within (upper
3/4) limits, then power supply is just fine - move on. If
numbers are below limits (or within bottom 1/4 of those
limits), then power supply is probably slowly failing. Its
that simple - only two minutes.

Again, it takes many times more minutes even to swap a
supply. Do not start wildly replacing things since that also
can complicate your solution. Procedure to verify power supply
integrity is that quick, that comprehensive, and that simple.
Nothing in those procedures is complex (except if you are
trying to learn too soon why you are doing things). Don't get
caught up trying to understand why you are doing that.
Learning the whys comes later with your next questions. Do
the procedure and don't even look back.

Also ignore nonsense about removing dust. Computers are
designed with significant dust accumulation already expected.
Furthermore, those who install too many fans to fix defective
hardware have excessive dust accumulation. If heat was a
problem, then when hair dryer (on high) was directed to a
defective component, component would fail immediately. Why?
Everything in that computer must work just fine even when room
temperature is above 100 degree F. OS also will not cause
this. If OS did, then fact would probably be posted in event
logs.

You have a perfect situation to learn which component caused
power failure. A power supply system is three components: the
PSU, a controller on motherboard, and power switch. Again,
get the meter. You cannot see electrons. Record voltage
readings of purple, green, and gray (etc) wires when power is
off AND when power switch is pressed AND when computer is on.
If you don't understand what those readings mean, then post
them here. You problem is that you are starving everyone
(including yourself) of important facts. I can take you far
beyond what other posters can accomplish BUT you must not
starve me of facts. Get the 3.5 digit multimeter.

Blindly follow the procedure in those previous posts. If
you don't understand, then post numbers here. Collecting
those numbers should take but a few minutes. You will learn
how to fish rather than just be feed fish. IOW you will
accomplish far more than just fix a computer.

In the meantime, start the process of getting additional
free tools. For example, every responsible computer
manufacturer provides comprehensive diagnostics on their web
site - for free. If manufacturer is not so responsible, then
start collecting freeware diagnostics such as memory (Memtst86
or Docmem), components (ie go to hard drive manufacturer for
his diagnostics), etc. Once we establish power supply
integrity, then we can move on to other 'usual' suspects. We
must first verify power supply integrity with the 3.5 digit
multimeter long before we can move on to other 'usual'
suspects.

Some obvious questions - your computer is plugged into a
properly safety grounded three prong outlet. All connected
peripherals share a common safety ground. You don't have
static electricity problems - the building has a humidifier.
No reason to assume anything. Computer repair is really quite
straight forward. You replace a part because part is
obviously defective. In but two minutes with a 3.5 digit
multimeter, you have all the facts necessary to say whether
power supply is good or bad.

If you do start looking at power supplies, then you are
asking for more and future problems if the supply is a
discounted (less than $60 retail) type. How do they lower
price? Forget to include essential functions that were even
defacto standard 30 years ago. Its called dumping. And so
many North Americans have so little computer knowledge as to
buy these 'defective by design' supplies.
 
Removing power cord is necessary to clear power supply
lockout. Where is that lockout function located? On
motherboard. Does he keep buying new parts and swapping - or
locate problem in minutes with a meter?

Where is a standard computer system that requires anything
near to 425 watts. This is the nonsense I am exposing. 425
watts is the urban myth posted, in part, because too many
computer experts don't even learn basic functions in a power
supply. They even buy 300 watt supplies that have a 425 watt
label. That intentional mislabeling on 'dumped' power
supplies is proof enough that all computers require more than
400 watts.

Most every computer is just fine with a 250 watt supply. In
another post, the 400 watt supply also listed amperage for
each individual voltage. Bottom line was the 400 watt supply
really was only 300 watts. These 'dumped' supplies are quite
common where repairmen don't first collect facts - instead
just wildly speculate and shotgun a solution. The typical
computer system needs no where near 425 watts.
 
I'll voice with most of the other folks here -- get a new (and better)
power supply. About a year ago a family member with a PC from one of
the cheaper manufacturers had the exact same problem as you are
describing. We replaced the power supply with a beefier, named-brand
PSU, and the problem went away (and stayed away).

If you PC was a low-cost purchase, it is highly likely that it shipped
with a lame power supply. Not only is 200W small, it's also likely
that the PSU is cheap and flakey.
 
Tom,

I'll be more than happy to try your suggestion(s) but I don't what a 3.5
digit multimeter is or where to buy one. How much are they?

Newtechie
 
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