ATT: w_tom. PC dead but MOBO light on???????

[p.mc]

(Snip/Tom replied)

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).

------------------------------------------------------------------------------------------

(My Test Results)
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

(original message)

 

[p.mc]

--
"Thanks for the info Andrew"

I must state that I am interested in the fault findind aspect of the problem
and was waiting for a response from "w_tom", as this subject has been quite
extensively discussed already further down in the posts as you may well see,
I look upon it as a project as I am already looking to buy a new machine for
my needs.
I'm just trying to learn a little as I go and if I can't do it myself, then
I'll have it repaired proffesionaly to retire it for the kids to use, thanks
for your comments though, I'm sure it benefits others too.


Regards
p.mc

 

[Curt Christianson]

Hi p. mc,

Although I'm late jumping in on this thread, I have been keeping track of
it.

This would be difficult to t-shoot over the telephone in real time, let
alone in a newsgroup.
For some excellent hardware info. (including power supplies) go to your
local library, and check out a copy of Scott Mueller's book Upgrading &
Repairing PC's. I think he's just releasing the 17th edition--so it's been
around a while. Beware, it may be *more* than you want to know (1000+
pages).

--
Curt BD-MVBT
http://dundats.mvps.org/
http://dundats.proboards27.com/index.cgi
http://www.aumha.org/
|
|
| --
| "Thanks for the info Andrew"
|
| I must state that I am interested in the fault findind aspect of the
problem
| and was waiting for a response from "w_tom", as this subject has been
quite
| extensively discussed already further down in the posts as you may well
see,
| I look upon it as a project as I am already looking to buy a new machine
for
| my needs.
| I'm just trying to learn a little as I go and if I can't do it myself,
then
| I'll have it repaired proffesionaly to retire it for the kids to use,
thanks
| for your comments though, I'm sure it benefits others too.
|
|
| Regards
| p.mc
|
|
| | > Take the power supply by itself or take case only to a reputable pc
shop,
| > they'll check youre system while you wait,usually free of charge...
| >
| > "p.mc" wrote:
| >
| >> (Snip/Tom replied)
| >> | >> > 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).
|| >>
| >> (My Test Results)
| >>
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
| >>
| >> (original message)
| >>
| >> > Hi
| >> >
| >> > I've been getting the BSOD for the last couple of months and I
thought
| >> > It
| >> > may have been my DVD/RW drive, (sorry no info because of first
| >> > sentence)
| >> > but
| >> > a couple of days ago I was converting an .avi to .vob,
(DVDsanta)...and
| >> > when
| >> > I went to check on it my PC was dead.
| >> >
| >> > The fuse in the kettle lead was ok so I opened up the tower and seen
| >> > that
| >> > the light on the MOBO was on, so I took out my HDD's and disconnected
| >> > everything except the 20 pin supply to the MOBO and tower and CPU
fans,
| >> > but
| >> > to my dismay when I pushed the power button on my PC the fans didn't
| >> > kick
| >> > in
| >> > (1...does there have to be a HDD with the OS installed for the fans
to
| >> > work?) So I'm under the impression that either the power supply is
| >> > knackered
| >> > (2...but why is the MOBO light on?) or The MOBO is knackered, but
then
| >> > again
| >> > I'm no expert and was hoping some tech buff could help in solving my
| >> > problem
| >> > (3...could the power supply have failed but have enough power for the
| >> > MOBO
| >> > light and nothing else??)
| >> >
| >> > I know the simple answer is to take it to a PC repair shop but I'd
| >> > rather
| >> > save money "as we all do" if someone may help me solve this.
| >> >
| >> > MOBO: ASUS A7A266
| >> > Power supply: FSP group inc
| >> > Model #: FSP250-60GTV (PF)
| >> > WinXP Home SP1
| >> >
| >> > A few piccys of the MOBO and Power supply
| >> >
| >>
http://i81.photobucket.com/albums/j238/npilcs/PowersupplyforASUSA7A266MOBO.jpg
| >>
| >> http://i81.photobucket.com/albums/j238/npilcs/ASUSMOBOLight.jpg
| >>
| >> http://i81.photobucket.com/albums/j238/npilcs/P1023151.jpg
| >> >
| >> > "Thanks"
| >> >
| >> > --
| >> >
| >> > Regards
| >> > p.mc
| >> >
| >>
| >>
|
|

 

[p.mc]

Hi Curt

Thanks for the info, my local library is only 100 yards from my front door.


As you say it's a mind blowing subject on the issue of buying a PSU to suit
the needs of a particularly specified machine you want it to support.
Below are just a few examples of what info I've been studying lately.
Some say a 300 - 350watt PSU is sufficient for the most demanding of
machines in today's market, although a PSU calculator will tell you exactly
what wattage PSU you require from the components and peripherals
installed...etc for your particular machine, which tends to be a lot higher
than 350watt in my case for a new machine, but doesn't explain that it's
calculated sum is what the machine would require if all it's organs (shall
we say) were running at full load at the same time, but in reality for the
majority, that wouldn't be the case.

It's quite stimulating reading, and after all's said and done you have to
make an informed decision from the pro's and con's of it all.

Excellent forums
http://www.silentpcreview.com/forums/viewforum.php?f=6

Handy sleuth
http://www.hardwaresecrets.com/article/370

PSU calculator and good info
http://extreme.outervision.com/psucalculator.jsp

Very informative site
http://tomshardware.co.uk/

 

[Curt Christianson]

p. mc,

Thanks--those are some good sites.

Check out Scott's book(s)--they are really good. I've been using them as a
reference for several years now.

For a new machine in todays world (P4's, kick*ss video, several HD's etc),
400 watt or even more is certainly not out of the question. Good luck, and
post back if need be.

--
Curt BD-MVBT

http://dundats.mvps.org/
http://www.aumha.org/

 

[p.mc]

Hi Curt

Yeah I'll definitely check that out.
BTW this is the specs for the new machine I'll probably purchase. It's
geared more for the gaming enthusiast, as I'm sure the kids will like ( "me
too", but I'm sure it's overkill for TW PGA Tour) but also it's future
proofed and there's lots of processing power and memory for video editing
and particularly audio orientated stuff, 'cause I do production cd's for a
theatre company (SFX). I'm just doing the sound tech for a musical called
"Like I've never been gone" at present for a community theatre group, it's
about Billy fury's early days and showing in the Gladstone theatre (Wirral)
with the original Fourmost performing throughout the show if anyone's
interested take a look at the link.

http://www.dinglecommunitytheatre.co.uk/


(New PC Specs)

Processor (CPU)
AMD ATHLONT 64 X2 5000+ (2.6GHz) 2 x 512K L2 Cache (Socket AM2)

Memory (RAM)
1024 MB CORSAIR XMS2 800MHz - LIFETIME WARRANTY! (2x512MB)

Motherboard
ASUS M2R32-MVP: Express 3200, DUAL DDR II, S-ATA II, 2 PCI

Operating System
WinXP Pro SP2

USB
6 x USB 2.0 PORTS

Hard Disk
80GB SERIAL ATA II HARD DRIVE WITH 8MB CACHE (7200rpm)
(already got 300gb & 250gb SATA HDD's but not sata2, I'll have to look into
that)

1st Optical Drive
18x +/- DVD WRITER (8x +/- Dual Lyr) (Lightscribe) (40x CD-RW)

2nd Optical Drive
18x +/- DVD WRITER (8x +/- Dual Lyr) (Lightscribe) (40x CD-RW)

Graphics Card
512MB RADEON X1950 CROSSFIRE EDITION + DVI + TV-OUT

2nd Graphics Card
512MB RADEON X1950XTX PCI Express + DVI + TV-OUT

Sound Card
Sound Blaster® X-FiT Fatal1ty FPS 7.1 + Black front kit

Network Facilities
2 WIRELESS 108Mbps CARDS (ONE SPARE FOR OTHER PC)

Floppy Disk Drive
1.44MB - 3.5" Floppy Disk Drive

Case
Stylish Silver/Black Sigma case + 2 front USB

Power Supply & cooling
700W Quiet Quad Rail PSU incl Case Fan & CPU Cooler
(the 600W may do the job as well??)

Firewire & Video Editing
ONBOARD 1394 FIREWIRE PORT

Monitor
WIDESCREEN 22 INCH TFT SIL/BLACK 1680 x 1050 5MS DVI

Keyboard & Mouse
Logitech® Internet Keyboard + Hotkeys

Mouse
Beige Logitech® Premium Optical Mouse

Speakers
CREATIVE INSPIRE 7.1 T7900 SPEAKER SYSTEM

Surge Protection
2 x Belkin 4 Socket 2M Surge Protector

Webcam & VoIP
Logitech® QuickCam® Messenger USB

 

[w_tom]

(My Test Results)
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
...

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

****0.01**** GREY
...

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

Purple wire at 5.7 volts - too high and potentially destructive.
Purple wire is power for the power supply controller - what tells power
supply to turn on and off. System would be unstable with 5.7 volts on
the purple wire.

Bad news. This defective supply may have also damaged the power
supply controller on motherboard if voltage exceeded 6 volts.
Hopefully, power supply contained electronics that keep that purple
wire voltage below a safety limit. Any other wire measurements after
only confirms a problem probably traceable to the purple wire. Green
wire at less than 0.8 volts says computer should have been powered on
constantly - never turns off. Controller electronics is telling
power supply via green wire to power on constantly. And yet that is
not happening. Just another reason to suspect a defective supply.
These numbers suggest power supply has failed and may (only may) have
damaged power supply controller on motherboard. Purple wire voltage
should never exceed 5.25. Safety circuits might have limited that
excessive voltage sufficiently so that it did not harm the power supply
controller if power supply contained that safety protection circuit.

Replace power supply. Then confirm voltages from the new power
supply are proper.

 

[p.mc]

Purple wire at 5.7 volts - too high and potentially destructive.
Purple wire is power for the power supply controller - what tells power
supply to turn on and off. System would be unstable with 5.7 volts on
the purple wire.

Bad news. This defective supply may have also damaged the power
supply controller on motherboard if voltage exceeded 6 volts.
Hopefully, power supply contained electronics that keep that purple
wire voltage below a safety limit. Any other wire measurements after
only confirms a problem probably traceable to the purple wire. Green
wire at less than 0.8 volts says computer should have been powered on
constantly - never turns off. Controller electronics is telling
power supply via green wire to power on constantly. And yet that is
not happening. Just another reason to suspect a defective supply.
These numbers suggest power supply has failed and may (only may) have
damaged power supply controller on motherboard. Purple wire voltage
should never exceed 5.25. Safety circuits might have limited that
excessive voltage sufficiently so that it did not harm the power supply
controller if power supply contained that safety protection circuit.

Replace power supply. Then confirm voltages from the new power
supply are proper.

Hi Tom

Here's the specs on my defective PSU... It looks and I believe to have been
a decent unit, so hopefully it may have stopped further
destruction to my MOBO, unfortunately this model is discontinued.
Ah well I got 10+years intensive slog from it. I might even give it a decent
burial if it's saved my MOBO..."It's the least I can do"
It's worked harder than a donkey on Blackpool beach.

http://www.tekheads.co.uk/s/product?product=602710

I'll install a new PSU and if the MOBO is sound, the kids can have the old
workhorse to use.

Once again thanks for sharing your knowledge, it's been very
educational...Also applies to all other posters.

Regards
p.mc

 

[w_tom]

Here's the specs on my defective PSU... It looks and I believe to have been
a decent unit, so hopefully it may have stopped further
destruction to my MOBO, unfortunately this model is discontinued.
Ah well I got 10+years intensive slog from it. I might even give it a decent
burial if it's saved my MOBO..."It's the least I can do"
It's worked harder than a donkey on Blackpool beach.

http://www.tekheads.co.uk/s/product?product=602710

Those specs appear to be a good model. Some of the numbers (and they
are too frugal with providing numbers) are slightly insufficient. For
example, overvoltage at 6.5 volts when it should be 6.3 volts. That's
quibbling since more important, overvoltage protection exists.
Something often forgotten on other supplies.

The 12 cm fan is typically small since to provide sufficient airflow,
a 12 mm fan would typically be very noisy. It also may be a typo -
maybe 120 mm. They don't provide the useful CFM or dB noise numbers.
But again, quibbling.

Not listed are amperages for each voltage. That missing spec is more
significant since it can be a reliabilty problem. Problem would be
apparent when using a meter while numerous peripherals were operated by
Windows simultaneously. For example, a power supply of same wattage
could output too few amps on one voltage. That voltage would drop
excessively even though computer still works. An example of why total
wattage is only a vague (ballpark) number.

Missing are noise numbers, highest and lowest AC mains voltages,
claims to comply with EMI/RFI standards, or even a claim to meet ATX
standards. Well, maybe it exists - just another oversight. After all,
this manufacturer does what so many fear to do - provides numerical
specs. Provided specs provide more confidence.

Criticized are some specs only to demonstrate what to look for. This
supply appears to be better than most discounted supplies. Sparkle
typically made good supplies. Specs that further imply a better
design:
Dielectric withstand:input / output 1800VAC for 1 second,
Input to frame ground 1800VAC for 1second

Necessary function that some discounted supplies may not provide.