PC dead but MOBO light on ???????

[p.mc]

--

Regards
p.mc

<snip>
In answer to your quesion, it depends. Most 20/24 pin connectors I've
seen are separatable. That is, they either consist of two connections
that
be attached to a 24 pin connection and singly attached to a 20 pin
connection
or they can be broken apart to do the same. While I've not seen an
advertised 20/24 pin that is fixed, I'd not be surprised if it exists
despite
being rather useless. If they are not detachable, I'd be very surprised
if
your MoBo configuration would be able to use this PS.

However, I wouldn't purchase this power supply. As stated quite
eloquently
by another poster, for proper performance a power supply needs more than a
certain number of watts and/or connectors. The PS should supply
consistent
power and, as another poster said, include features that probably are not
included if not advertised.

Wow! this is getting hard. I did say I chose it on price and wattage because
I haven't a clue, and I'm glad you have put me off it, but it would have
been even better if you could have given me an alternative.
Never mind thanks.

 

[p.mc]

i don't think thats a good idea because:

1) if you dont have any training with electronics
and the equipment. So you can seriously hurt yourself
by electricity.

2) your mobo was designed prior to 2001
and outdated. Neither your mobo and p.s.
can handle new devices like dvd's, etc....

**Not true**

you might succeed with simply buying
a new p.s. if that is the problem. but
it will likely overload your old mobo
and you will find yourself in the same pickle.

**I wish someone could say, here you go this is what is needed, because I
would blindly buy a PS as long as it has the right connectors, but
unfortunately I'm getting told it's not right but no explanation why it
would overload my MOBO. So until then I suppose I'll always be naive.**

of course, you can do as you wish. But don't
beleive yourself to be compentant with
diagnosing equipment, especially out dated
and ready for the dumpster electronics.

** Don't sell yourself short it's not rocket science, and if I'm prepared
for someone to tell me to shove a couple of probes into a non lethal
connector so I can ascertain whether something is working or not then I see
no problem with that.**

I have reason to beleive that if you were
then you would obtain the schematics for
the mobo and for the p.s., have experience
with multimeters and o-scopes, solder, soldering
irons, etc....

do yourself a favor and save time, money and possibly your own life by
getting a cheaply priced pc, that is
more powerful than your old 500 mhz pc.

good luck....

**1.4mhz**

 

[p.mc]

the following is a new pc on the low
end. And if you compare the specifications
to what you have now, you will see that it
is much more powerful.

Your current cpu is rated at 500 mhz, that
is if it is not actually a 250mhz that has a clock doubler.

However, the new one that is on the low end
of the market is over 3 ghz. (yours is .5 ghz)

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1221657&sku=BTO 970811

**I paid £1200 for this machine 10 years ago when I first got it, it was
classed as a top end gamer PC at the time and the CPU is 1.4ghz. I wrote
1.4mhz in an earlier post my mistake, but to be honest ben I wouldn't buy
one that cheap, my graphics and sound card cost more than that..) **

 

[p.mc]

Hi Shenan

With respect....If this has gone on too long for you then I suggest you
ignore the thread and not post, I see your point, but to be honest I'd like
to know how to use a multimeter and fault find for future reference. What
people are losing sight of here is, I didn't know whether the MOBO or the PS
had failed, it turns out that it could be one or the other, but for the sake
of a Fiver and a lesson from someone on how to test the PS, it's not a bad
price to pay unless I get killed poking around the MOBO, which we've already
established that, that is an improbability. So logic tells you to start from
the cheapest option if you don't mind learning something in the process.

 

[McSpreader]

I wish someone could say, here you go this is what is needed

As Leythos spotted, your motherboard is probably faulty: note the
bulging electrolytic capacitors evident in your second photo. If it
hasn't already failed, it will soon. See here for details of the
symptoms and causes:

<http://en.wikipedia.org/wiki/Capacitor_plague>

In my experience, repair of a motherboard in this state is rarely
successful.

The PSU could also be faulty and needs to be tested but (obviously)
not against a very suspect motherboard.

Based on your earlier posts, a DIY repair of the PC may be beyond
your current skills. In the UK, a professional repairer's fee would
be around half the price of an entry-level replacement base unit.

How do the economics of those alternatives compare where you're
located?

 

[Shenan Stanley]

Hi Shenan

With respect....If this has gone on too long for you then I suggest
you ignore the thread and not post, I see your point, but to be
honest I'd like to know how to use a multimeter and fault find for
future reference. What people are losing sight of here is, I didn't
know whether the MOBO or the PS had failed, it turns out that it
could be one or the other, but for the sake of a Fiver and a lesson
from someone on how to test the PS, it's not a bad price to pay
unless I get killed poking around the MOBO, which we've already
established that, that is an improbability. So logic tells you to
start from the cheapest option if you don't mind learning something
in the process.

As I stated in a previous post:

Each their own... If the OP enjoys testing and fiddling with such things -
fantastic - go on. However - there are other options - faster and possibly
less expensive in the long run. Presenting those options is a valid point -
just as presenting the testing options is a valid point.

I was just presenting options. My argument is not with you wishing to do
the testing.

I feel the motherboard is your problem.
I have seen the bulging capacitors myself.
In fact - Dell had to replace 45 motherboards for me last year due to this
exact issue.

If you enjoy fiddling - fiddle away. ;-)

 

[Leythos]

but to be honest I'd like
to know how to use a multimeter and fault find for future reference. What
people are losing sight of here is, I didn't know whether the MOBO or the PS
had failed, it turns out that it could be one or the other, but for the sake
of a Fiver and a lesson from someone on how to test the PS

The Problem is that testing with a multimeter is not going to show
anything if it's a CAP problem. The tests will show the proper voltages
on all the connectors, so the PSU will show that it's good. There is no
multimeter test to show that bulging caps are bad, unless they short out
completely, and then the multimeter will show a drop/loss of power and
it will seem like the PSU is bad, so, it's a catch 22 situation.

 

[teldave]

Hi,

I often have to repair PC's as part of my business and so take the time
I spend fixing as part of the cost of the repair.
I always have spare power supplies and find this is the best way to
test. A PSU can be faulty but test OK with the meter, load having a big
part to play. (they are cheap to keep as a spare IMHO)
Some way back you say you keep your MB "hovered" and clean. You should
know that a hover is charged with static and could blow your MB easily,
I'm amazed the MB lasted so long. Sticking meter probes in to any hole
is living life in the danger zone.
There are canned cleaners to blow the dust away and I use a horse hair
bush for the rest.. An anti-static mat also helps.
Cleaning for me means power cord in but power off, equalise yourself
electrically, tools and yourself by touching the metal case. This
discharges static through earth.or better still use an anti-static
strap. One of the early courses I did the tutor failed anyone working
on a computer or parts without a static strap on. I get a lot of work
to repair machines because people have dived in and blown things up or
worst still caused a damged chip that let the computer run but produces
some really strange fault.
For me in the workshop it"s better after proving the MB faulty is to
just buy a MB, processor and memory kit and put it all together. (Kit
meaning parts bought together to be compatable with each other)
You may have to do a repair install of the OS and activate windows
again to finish the job.

Good luck

 

[w_tom]

To be honest you may be right, but this is not just about saving a few bob
now, I am genuinely interested in the fault finding aspect.

An English teacher once promoted a myth that 'Paul was Dead' - citing
Abbey Road cover as proof. She did not learn the relationship between
knowledge and 'why'. She just somehow knew because Paul had no shoes.
Such people are easily deceived.

If one is a cost controller, then one is only concerned with making
it work ASAP. Therefore those who never learned 'why' also could not
hear every engineer saying, "Don't launch". Engineers were not even
allowed to vote when they launched Challenger anyway. To not ask why
should have been called criminally negligent manslaughter. But many of
us never learn why failures are so easily avoided. We instead know
rather than first ask 'why'.

We learn 'why' - and this is most important - to become powerful
problem solvers. Those who don't learn how to ask 'why' are good
assembly line workers or cannon fodder for the front line. Those who
solve problems by learning 'why' innovate - advance mankind. It starts
by learning the little things - even a 3.5 digit multimeter and how to
identify a defective power supply in but a minute.

The only reason for so many posts? So many never even learned how to
use a 3.5 digit meter - instead use 'shotgunning' rather than first ask
'why'. Learning how to ask 'why' is not trivial. But again, that is
why the military wants everyone graduated as an engineer. Philosophy
of that education teaches the power of and ow to ask 'why'. So many
others only shotgun. "I feel Saddam must have WMDs, therefore he has
WMDs." A classic example of what happens when not learning how to ask
'why'. Learning by asking 'why' creates a powerful problem solver.
Anyone can shotgun. But a good problem solver is difficult to find.

 

[w_tom]

Wow! this is getting hard. I did say I chose it on price and wattage because
I haven't a clue, and I'm glad you have put me off it, but it would have
been even better if you could have given me an alternative.

Just providing a numerical specification sheet is a major difference
between a supply dumped in the market for higher profits verses one
designed to do what is required. Below is an abridged list that all
power supplies must accomplish and that should be defined in that
numerical specification sheet:

Specification compliance: ATX 2.03 & ATX12V v1.1
Acoustics noise 25.8dBA typical at 70w, 30cm
Short circuit protection on all outputs
Over voltage protection
Over power protection
100% hi-pot test
PFC harmonics compliance: EN61000-3-2 + A1 + A2
EMI/RFI compliance: CE, CISPR22 & FCC part 15 class B
Safety compliance: VDE, TUV, D, N, S, Fi, UL, C-UL & CB
Hold up time, full load: 16ms. typical
Efficiency; 100-120VAC and full range: >65%
Dielectric withstand, input to frame/ground: 1800VAC, 1sec.
Dielectric withstand, input to output: 1800VAC, 1sec.
MTBF, full load @ 25°C amb.: >100k hrs

Power supplies sold to computer assembler without electrical
knowledge are often missing such functions - often at fully retail
prices well below $60. $60 does not say the supply is good.
Appreciate the logic. Well below $60 means it is selling for a loss or
is missing essential functions - especially if numerical specifications
are not provided.

 

[databaseben]

yeh, you would have
more success finding a powersupply
like the one you had, eg 250W.

because of the ever evolving technology,
hardware connections are redesigned to
avoid the mixing and matching affect.

the p.s. you acquired can likely be modified
to accomadate your old motherboard (mobo).
but i have a distinct feeling that your old mobo
won't last very much longer. Further, it
cannot accomadate todays technology, eg
software and peripherials.

an analogie that may help see this
with a different aspect would be like
a heart transplant. You might can figure
out why it would not be a good idea
transferring a heart of a 20 year vigourous
male into an 80 year old one.

I think you are a bit of a computer savvy
and instead of buying a multimeter and
tinkering with the old mobo your better
off simply ascertaining newer components.

You can save some money by purchasing
the mobo w/cpu as a bundle, ram and the p.s.,
and a cpu fan.

you already have the cabinet and fans and
a dvd device and hopefully you have
a retail version of windowsxp too...

I am sure that you would be better off
building your pc, rather than buying a
multimeter for a one time use, only to
discover that

1) the old components
are a waste of time and money to maintain,

2) software and devices are no longer
available for older mobo's and

3) buying a multimeter for use this one
time wasn't a good idea (as i think i read in a prior posting somewhere in
this abyss)....

since this is an abyss of a thread
create a new post/thread if you
encounter any problems. my guess
is that you have received enough
information from "everywhere" that
you have a reasonable idea which way
to go......

 

[databaseben]

ps: no need to provide
a response to me herein.

i'm unflagging this thread/abyss
but i do hope to hear from you
again, especially with how much
more fun you are having with your
pc - newer one hopefully.

 

[p.mc]

Hi Dave

I suppose I have been lucky getting ten years from the machine, I do believe
the regular cleaning must have attributed to its longevity, I did used to
use release any static by grounding myself and a cheap paintbrush and soft
toothbrush as tools, suppose like oiling the wheels of my engine
Still I haven't had time to get a multimeter, but I will soon, I've got my
brother visiting today for a long weekend so it might have to wait till the
next weekend.

Thanks for the advice, It's all being put to good use. Knowledge is a
wonderful thing, especially if someone gives it to you for free..."Many
thanks."

 

[p.mc]

Hi all

I'd like to thank you for your advice and comments, we've had some ups and
downs but for most of it I'm a lot more wiser and knowledgeable for it
thanks to your time and free advice. I've said it before and I'll say it
again, "Aren't newsgroups a wonderful thing" I started out as many do
knowing nothing about how a PC runs, form the simplest questions as "how do
I change my display size on my screen" to "add hardware and reformat...etc
etc" and all without the intervention of a night... college or university, I
now know and have learnt all that from the humble NG's.

And it's all down to ordinary people, whether it be the bank manager asking
the housewife how long to boil an egg, to the housewife asking how does one
go about getting a mortgage, both valid information, one being no more valid
than the other, other than the latter having more input to be qualified to
reply )

If a 5 year old can recite all the states in America you may think he/she
may be a genius in the making, and on the other hand if another child can
systematically recite 26 letters in order (abc) or 50 numbers then it's not
so impressive, ("it's the same thing.") I believe the majority learn the
latter as standard, but because only the few would be learnt the first, we
assume a cleverer mind, but his/her older brother may need to know that
information for a school test one day and gladly share it, so it was useful
after all.

So I'm still going to buy a 3.5 digit multimeter and perform the tests
provided because that's another small skill I'll have learnt even though the
PS may still give a good reading or it may but in a minute show a total
failure, but most of all it's a useful tool even for the simplest of jobs,
and after all's said and done you'll all probably want to strangle me!!...
Because even though I've had the machine for approx ten years without any of
the major pre installed hardware fail,(with the exception of a few DVD/RW
and upgrading to more and bigger HDD's)

I do have a laptop too, and at this point in time I'm on another machine to
which I've added my 300gb storage HDD. In all honesty my problem machine
will be retired to the kids to play games and study on, but that doesn't
stop me from wanting to learn how to fault find because that's another
string to my bow as I said I started out knowing nothing about how a PC
works or gardening/building/plumbing/local government/pet bird care/ how to
boil an egg, and I've learnt all this thanks to the wonderful people who
share knowledge through NG's.

And here's the killer...I do have £2000 for the next generation
machine...Hopefully in another ten years you'll still be helping me keep it
in tip top condition and I may be useful to someone else for the knowledge
I've been taught.

Apologies to posters who may have thought it was too much time wasted on
the subject.

Watch this space ;-))

 

[Leythos]

What you say is true in a strictly hard-cash sense, and I constantly have to
remind myself that more than a couple of hours spent on a basic system-unit
is probably time wasted.

However, there are hidden costs in replacing the unit, greatest of which is
that the software -including the OS- cannot be transferred, but will have to
be reinstalled, and then painstakingly reconfigured to work properly, right
from the ground up. Where there's specialist software on the computer, this
might take days of work, rather than hours. When these additional costs of a
new computer are taken into account, the repair-option suddenly looks very
attractive.

This is not entirely true - the word "Painstakingly" should not be used,
as most XP installs are painless, as are most application installs.
Also, if replacing the motherboard, in many cases, a repair option can
bring the old hard drive into a usable state on a new motherboard.

This issue does seem to be a fundamental one with Windows; from my
admittedly limited experience, Linux doesn't suffer from this the same
upgrade-problems, you can generally transfer a Linux distro in-toto from one
computer to another.

Generally is the key word.

 

[p.mc]

In but a minute with a 3.5 digit multimeter, trim the list of
suspects down to only power supply or motherboard, or ..... That mains
testing light cannot report anything useful because numbers are
required.

Light says power cord connects to AC mains. Light does not say any
voltage is sufficient. Only meter numbers can say that. Start by
measuring voltage on purple wire by pressing meter probes into 20 pin
nylon connector for purple wire and to any black wire (or touch
chassis). With computer powered off (and light still illuminated), that
number must exceed 4.87 (and it probably will).

http://i81.photobucket.com/albums/j238/npilcs/silverlinedigitalmultimeter.jpg
(Tested with these settings and positions on multimeter)

http://i81.photobucket.com/albums/j238/npilcs/PCfulload.jpg
(all connections and peripherals connected and light still illuminated)

****5.7**** PURPLE

Next take the number

for green wire both before and when power switch is pressed. That
number should be above 2.0 volts and drop to less than 0.8 volts when
switch is pressed. What happens here is very informative.

****0.02...both switched and unswitched **** GREEN

Next, the gray wire. It must rise to well above 2.4 volts within
second of the power switch pressed. I suspect either voltage will not
move or will rise and then fall.

****0.01**** GREY

Now measure any red, orange and yellow wires when switch is pressed.
Assuming the green wire voltage did drop, then each voltage here
should rise up (and then will probably fall). Any voltage that does
not rise up, then look for a short circuit for that voltage on
motherboard. If all voltages do rise up, then within a second, each
voltage must achieve more than 3.23, 4.87, or 11.7.

****0.47*** RED (un/switched - swithched)
****0.30**** ORANGE (un/switched - swithched)
****1.19**** YELLOW (un/switched - swithched)

Information from those quick measurements either make it obvious
which is the suspect or post those numbers here for better analysis.

Regards
p.mc

 

[Andy]

http://i81.photobucket.com/albums/j238/npilcs/silverlinedigitalmultimeter.jpg
(Tested with these settings and positions on multimeter)

http://i81.photobucket.com/albums/j238/npilcs/PCfulload.jpg
(all connections and peripherals connected and light still illuminated)

****5.7**** PURPLE

The Standby voltage is too high. It should be 5 volts +/- 5%. I'm not
sure if it's high enough to have destroyed or cause to malfunction the
power control circuit on the motherboard. I would replace the power
supply.

Next take the number

****0.02...both switched and unswitched **** GREEN

This signal (PS_ON#) is driven by the motherboard. When it goes low,
which your measurement says it is, the power supply should turn on.
Since the power supply does not go on, either the power supply is
defective or there's a short on one of the power supply outputs.

PS_ON# seems to be stuck low. Other than a defect in the motherboard
power control circuit, the reason for that could be the BIOS is set so
the computer automatically powers up when AC power resumes after a
power loss situation.

Try removing the ATX power connector from the motherboard, and then
measure the green wire again. I would expect it to be high (> 2
volts). If so, disconnect all the power supply power connectors, and
plug the ATX power connector into the motheboard, and measure PS_ON#
again.

 

[p.mc]

Hi Andy
Results below

This signal (PS_ON#) is driven by the motherboard. When it goes low,
which your measurement says it is, the power supply should turn on.
Since the power supply does not go on, either the power supply is
defective or there's a short on one of the power supply outputs.

PS_ON# seems to be stuck low. Other than a defect in the motherboard
power control circuit, the reason for that could be the BIOS is set so
the computer automatically powers up when AC power resumes after a
power loss situation.

Try removing the ATX power connector from the motherboard, and then
measure the green wire again. I would expect it to be high (> 2
volts).

****4.67****

If so, disconnect all the power supply power connectors, and

plug the ATX power connector into the motheboard, and measure PS_ON#
again.

****0.02****(switched & un/sw)

Do you think the power supply has definitely had it then?

Thanks Andy

 

[Uncle Grumpy]

Do you think the power supply has definitely had it then?

Fer crissakes, pop for a new one and put it in. What'll it cost... $30?

 

[Andy]

Hi Andy
Results below


****4.67****

If so, disconnect all the power supply power connectors, and

****0.02****(switched & un/sw)

Do you think the power supply has definitely had it then?

Looks like it. Seems like the motherboard power control circuit might
have problems too.
One last thing you can try is remove the ATX power connector from the
motherboard, and short PS_ON# to ground (one of the black wires) and
see if the power supply turns on.