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PC no longer booting



 
 
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  #16  
Old May 9th 11, 03:33 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

SC Tom

Couple of messages on this issue from yourself and a chap called Paul that
I couldn't review because ...."News servers regularly expire articles as
they get older to make space available for newer articles" Looking at date
and time of both posts how they could be classified as old when they were
only posted 2 - 3 hours ago I don't know!. Anyway...................

Double checked for speaker. Definitely nothing that I can see or find.

I've removed processor chip and heatsink cleaned out dust from fan, heat
sink and mobo. cleaned off old thermal paste and renewed. Re-installed but
result on start is still the same.

Reviewed my notes on actions to date to see if I've missed anything in
diagnosis and to see if there is anything else I can look at.
****Interesting****

I said at start that original reported fault was problem with USB KB and
mouse not working. I used PS/2 KB and mouse when I started to look at PC.
On starting up there had obviously been a problem as I had repair or normal
start option waiting me.. I chose normal start, which it (eventually) did
and I was able to update and perform multiple restarts before turning off
for the night. This is the *****interesting**** bit. What I failed to
state when I restarted in the morning ..............I had removed PS/2 KB
and mouse and installed USB KB and mouse...............On start up, I
immediately got unrecoverable hardware error (0x0124). On restart, no
video, nothing!

I think whatever the (USB) problem was, the impact of using USB KB/mouse
was to take out the mobo. I really can't come up with any other answer. I
don't think there is anything else I can do; unless you know better, other
than inform my friend his PC is dead.



"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
SC Tom,

No POST just blank from the moment it's turned on. No beep code sounds
at all but that may be because I can't see/find speaker anywhere in
(Packard Bell) case.

See all by reply to Bill re additional checks etc. I'm beginning to
think that mobo has gone AWOL. Would you agree ???



From the rest of your replies here, I'd be leaning that way, too. If
everything has been unplugged/removed, and there still are no beeps, it's
probably the mobo, power supply, or a bad connection between the two.

Odds are, there isn't an off-board speaker. Most have the speaker built
onto the mobo- look for a round black plastic piece about the diameter of
a dime. That would be your speaker.
--
SC Tom




"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
Hi,

Received friends PC last night with a view to fixing for him. (Only)
reported fault was no (USB) KB or mouse (?), Mobo is Gigabyte
GA-K8NUSL-RG, AMD 64 Dual Core 4600+ processor, 2 x 1 GByte RAM. and
dual GCSLISW-RH graphics cards running in SLI mode. O/S is Windows 7
Ultimate

Connected PS/2 KB and mouse and on boot presented with DOS window
indicating error had occurred and whether I required to repair (via
CD) or start windows normally. Opted to start normally (why not) just
to see what happened. It got to Windows starting icon and hung for
some time and just as I was about to press reset it continued to
desktop after completing (earlier) update installs

Decided to remain with PS/2 configuration and check for further updates
to PC. Eventually completed all updates after a few hours work with
multiple restarts and restarted one last time to check all OK and then
switched off until this morning.

Started up this morning and promptly got unrecoverable hardware error
code 0x0124. Pressed restart and on reboot no video - nothing showing
on screen at all! That is still position

One suspect is Graphics because previously experienced starting delays
on another win 7 PC when booting, Turned out that despite win 7
compatibility testing, card wasn't in fact compatible. Similar time
lag on this PC. Also, there was an update for the card which, I'm now
regretting, I downloaded and installed. Didn't have problems using
last night with multiple restarts since installation of update. I
don't have a spare PCI express graphics card to try so stuck. Am I
barking up the wrong tree? Is there something or anything else I should
be looking at/trying. Help much appreciated.



Upon restart, did you get your POST screen, or is it just blank from the
moment it's turned on?

If you get the POST screen, then press F8 repeatedly and see if you can
start up in Safe Mode or Safe Mode with Command Prompt.
If you can get into Safe Mode, roll back the driver for the video card
through Device Manager.
If no Safe Mode, but you can get into Safe Mode with Command Prompt, you
can attempt to restore your system to an earlier time by typing in

%systemroot%\system32\restore\rstrui.exe (for Windows XP)
%systemroot%\system32\rstrui.exe (for Windows 7)

and pressing Enter (I know you said the OS is Win7, but this is an XP
group :-) ). The normal System Restore GUI will come up, and you can
then pick a time before the driver update was installed.

If you can't get into either mode, turn the PC off, pull the power cord,
open it up, and remove the video card. Plug it back in and turn it on.
You'll get a series of beeps, meaning that there is no video card
installed. Turn it back off, unplug it, and put the card back in. Turn
it on and see if you have video again. If so, roll back the video driver
as soon as you are able to navigate through Windows. (Of course, this
suggestion is moot if it's an onboard video chip.)
--
SC Tom


Ads
  #17  
Old May 9th 11, 03:44 PM posted to microsoft.public.windowsxp.hardware
BillW50
external usenet poster
 
Posts: 5,556
Default PC no longer booting

In ,
barrowhill wrote:
SC Tom

Couple of messages on this issue from yourself and a chap called
Paul that I couldn't review because ...."News servers regularly
expire articles as they get older to make space available for newer
articles" Looking at date and time of both posts how they could be
classified as old when they were only posted 2 - 3 hours ago I don't
know!. Anyway...................


Well Paul's comments were quite excellent. So I'll repost it here below.


From: "Paul"
Subject: PC no longer booting
Date: Monday, May 09, 2011 6:55 AM

The computer cases I have here, they like to hide the speaker in the
front plastic fascia. If you take the thing all apart, eventually you
might be rewarded with a 2" speaker or the like.

If you trace where the SPKR connector and two wire cable go, you'll
eventually find it. It can't escape :-) Start at the motherboard PANEL
header, and work your way back, following the two wire twisted pair.

When I get a new computer case, I take special pleasure in disassembling
the thing, and removing the bits I don't want. For example, the first
thing to go, are the front USB or Firewire ports, the audio connectors
and wires. By removing those and saving them for later, I have less
cruft hanging down inside the computer. Since my computers are always at
desk level, and oriented so I have access to the rear connectors, there
is no need for front connectors. I started this practice, after finding
wiring errors on some of my older cases, and rather than wasting time
catching those errors before they burn or damage something, I just got
in the habit of tearing them out.

But I always keep the speaker, due to the ability to do "beep tests" if
something breaks.

Some computers (Dell) have a four LED display on the case, using two
color LEDs. And those can give diagnostic codes, indicating a problem.

Some retail motherboards (typically Nvidia motherboards resold by other
companies), have a two digit POST code right on the motherboard surface.
The actual codes aren't of much use, but the ability to see whether the
POST display will work at all, helps identify whether the processor is
able to read the BIOS or not. If the POST display stays stuck at 0xFF or
0x00, then chances are the processor isn't running for some reason
(stuck in reset, no power etc). Any other of the remaining 254 decimal
codes, indicates something is going on, but usually there is no reliable
documentation of the code values, and even if there is documentation,
the codes don't focus on a single fault at all. So they're not really
that useful. In all the cases, where a person has posted the value they
got off their display, when I looked up the code, no good came of it
(the user was none the wiser).

Now, a feature I liked, but which is no longer used, was the Winbond
audio post device. It was a chip that would play back voice messages, to
tell you what was going on. These would be triggered by writing a
control byte in the chip, via BIOS code. But unlike the POST display,
the events were designed to be a bit more useful. The audio was coupled
into the regular Line Out connector, so the "bitchen betty" voice came
out of your amplified external computer speakers. Asus put that on their
motherboards for several years, and then gave up on it. It probably cost
them a dollar or two per motherboard (audio playback chip plus serial
EEPROM). There was even a utility, so you could record your own voice
for the samples if you wanted (it took 30 to 60 minutes to re-program
the serial EEPROM).

By comparison, the computer case (internal) speaker is a bit boring, but
at least it is common enough, that some useful testing can be done.

Paul



  #18  
Old May 9th 11, 04:09 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

SC Tom,

Definitely no speaker to found !

Removed PC chip and heat sink. Cleaned out all dust and wiped off paste.
Fresh coating of thermal paste applied. Put back but on start up same
issue.

Reviewed notes of actions taken and ***** interesting***** observation

As stated at outset, reported problem was non functioning USB KB and mouse.
I started with PS/2 mouse. On start-up there had been a problem as I was
presented with the option to repair or start normally. I chose to start
normally which it (eventually) did. I switched off after performing updates
with multiple restarts. No issues during this process and successfully
switched off for the night.

No here is *****interesting***** bit. Before I started up in the morning, I
removed PS/2 KB and mouse and inserted USB KB and mouse. On boot immediate
unrecoverable hardware error reported and then on restart - no video,
nothing

Suspect that the impact of using the USB KB and mouse has now resulted in
taking out the motherboard. I can't think of any other explanation as
believe tried all options. Would you agree ??. Only option I can see now
is to advise my friend that new mobo (or PC) is required.

"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
SC Tom,

No POST just blank from the moment it's turned on. No beep code sounds
at all but that may be because I can't see/find speaker anywhere in
(Packard Bell) case.

See all by reply to Bill re additional checks etc. I'm beginning to
think that mobo has gone AWOL. Would you agree ???



From the rest of your replies here, I'd be leaning that way, too. If
everything has been unplugged/removed, and there still are no beeps, it's
probably the mobo, power supply, or a bad connection between the two.

Odds are, there isn't an off-board speaker. Most have the speaker built
onto the mobo- look for a round black plastic piece about the diameter of
a dime. That would be your speaker.
--
SC Tom




"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
Hi,

Received friends PC last night with a view to fixing for him. (Only)
reported fault was no (USB) KB or mouse (?), Mobo is Gigabyte
GA-K8NUSL-RG, AMD 64 Dual Core 4600+ processor, 2 x 1 GByte RAM. and
dual GCSLISW-RH graphics cards running in SLI mode. O/S is Windows 7
Ultimate

Connected PS/2 KB and mouse and on boot presented with DOS window
indicating error had occurred and whether I required to repair (via
CD) or start windows normally. Opted to start normally (why not) just
to see what happened. It got to Windows starting icon and hung for
some time and just as I was about to press reset it continued to
desktop after completing (earlier) update installs

Decided to remain with PS/2 configuration and check for further updates
to PC. Eventually completed all updates after a few hours work with
multiple restarts and restarted one last time to check all OK and then
switched off until this morning.

Started up this morning and promptly got unrecoverable hardware error
code 0x0124. Pressed restart and on reboot no video - nothing showing
on screen at all! That is still position

One suspect is Graphics because previously experienced starting delays
on another win 7 PC when booting, Turned out that despite win 7
compatibility testing, card wasn't in fact compatible. Similar time
lag on this PC. Also, there was an update for the card which, I'm now
regretting, I downloaded and installed. Didn't have problems using
last night with multiple restarts since installation of update. I
don't have a spare PCI express graphics card to try so stuck. Am I
barking up the wrong tree? Is there something or anything else I should
be looking at/trying. Help much appreciated.



Upon restart, did you get your POST screen, or is it just blank from the
moment it's turned on?

If you get the POST screen, then press F8 repeatedly and see if you can
start up in Safe Mode or Safe Mode with Command Prompt.
If you can get into Safe Mode, roll back the driver for the video card
through Device Manager.
If no Safe Mode, but you can get into Safe Mode with Command Prompt, you
can attempt to restore your system to an earlier time by typing in

%systemroot%\system32\restore\rstrui.exe (for Windows XP)
%systemroot%\system32\rstrui.exe (for Windows 7)

and pressing Enter (I know you said the OS is Win7, but this is an XP
group :-) ). The normal System Restore GUI will come up, and you can
then pick a time before the driver update was installed.

If you can't get into either mode, turn the PC off, pull the power cord,
open it up, and remove the video card. Plug it back in and turn it on.
You'll get a series of beeps, meaning that there is no video card
installed. Turn it back off, unplug it, and put the card back in. Turn
it on and see if you have video again. If so, roll back the video driver
as soon as you are able to navigate through Windows. (Of course, this
suggestion is moot if it's an onboard video chip.)
--
SC Tom


  #19  
Old May 9th 11, 04:12 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

SC Tom,

Definitely no speaker to found !

Removed PC chip and heat sink. Cleaned out all dust and wiped off paste.
Fresh coating of thermal paste applied. Put back but on start up same
issue.

Reviewed notes of actions taken and ***** interesting***** observation

As stated at outset, reported problem was non functioning USB KB and mouse.
I started with PS/2 mouse. On start-up there had been a problem as I was
presented with the option to repair or start normally. I chose to start
normally which it (eventually) did. I switched off after performing updates
with multiple restarts. No issues during this process and successfully
switched off for the night.

No here is *****interesting***** bit. Before I started up in the morning, I
removed PS/2 KB and mouse and inserted USB KB and mouse. On boot immediate
unrecoverable hardware error reported and then on restart - no video,
nothing

Suspect that the impact of using the USB KB and mouse has now resulted in
taking out the motherboard. I can't think of any other explanation as
believe tried all options. Would you agree ??. Only option I can see now
is to advise my friend that new mobo (or PC) is required.


"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
SC Tom,

No POST just blank from the moment it's turned on. No beep code sounds
at all but that may be because I can't see/find speaker anywhere in
(Packard Bell) case.

See all by reply to Bill re additional checks etc. I'm beginning to
think that mobo has gone AWOL. Would you agree ???



From the rest of your replies here, I'd be leaning that way, too. If
everything has been unplugged/removed, and there still are no beeps, it's
probably the mobo, power supply, or a bad connection between the two.

Odds are, there isn't an off-board speaker. Most have the speaker built
onto the mobo- look for a round black plastic piece about the diameter of
a dime. That would be your speaker.
--
SC Tom




"SC Tom" wrote in message ...

"barrowhill" wrote in message
...
Hi,

Received friends PC last night with a view to fixing for him. (Only)
reported fault was no (USB) KB or mouse (?), Mobo is Gigabyte
GA-K8NUSL-RG, AMD 64 Dual Core 4600+ processor, 2 x 1 GByte RAM. and
dual GCSLISW-RH graphics cards running in SLI mode. O/S is Windows 7
Ultimate

Connected PS/2 KB and mouse and on boot presented with DOS window
indicating error had occurred and whether I required to repair (via
CD) or start windows normally. Opted to start normally (why not) just
to see what happened. It got to Windows starting icon and hung for
some time and just as I was about to press reset it continued to
desktop after completing (earlier) update installs

Decided to remain with PS/2 configuration and check for further updates
to PC. Eventually completed all updates after a few hours work with
multiple restarts and restarted one last time to check all OK and then
switched off until this morning.

Started up this morning and promptly got unrecoverable hardware error
code 0x0124. Pressed restart and on reboot no video - nothing showing
on screen at all! That is still position

One suspect is Graphics because previously experienced starting delays
on another win 7 PC when booting, Turned out that despite win 7
compatibility testing, card wasn't in fact compatible. Similar time
lag on this PC. Also, there was an update for the card which, I'm now
regretting, I downloaded and installed. Didn't have problems using
last night with multiple restarts since installation of update. I
don't have a spare PCI express graphics card to try so stuck. Am I
barking up the wrong tree? Is there something or anything else I should
be looking at/trying. Help much appreciated.



Upon restart, did you get your POST screen, or is it just blank from the
moment it's turned on?

If you get the POST screen, then press F8 repeatedly and see if you can
start up in Safe Mode or Safe Mode with Command Prompt.
If you can get into Safe Mode, roll back the driver for the video card
through Device Manager.
If no Safe Mode, but you can get into Safe Mode with Command Prompt, you
can attempt to restore your system to an earlier time by typing in

%systemroot%\system32\restore\rstrui.exe (for Windows XP)
%systemroot%\system32\rstrui.exe (for Windows 7)

and pressing Enter (I know you said the OS is Win7, but this is an XP
group :-) ). The normal System Restore GUI will come up, and you can
then pick a time before the driver update was installed.

If you can't get into either mode, turn the PC off, pull the power cord,
open it up, and remove the video card. Plug it back in and turn it on.
You'll get a series of beeps, meaning that there is no video card
installed. Turn it back off, unplug it, and put the card back in. Turn
it on and see if you have video again. If so, roll back the video driver
as soon as you are able to navigate through Windows. (Of course, this
suggestion is moot if it's an onboard video chip.)
--
SC Tom


  #20  
Old May 9th 11, 07:28 PM posted to microsoft.public.windowsxp.hardware
SC Tom[_3_]
external usenet poster
 
Posts: 4,089
Default PC no longer booting


"Paul" wrote in message
...
SC Tom wrote:


*** You're correct on that; my old OEM board had the piezo device on it,
but my new (to me) M2NPV-VM doesn't. It has the solder points and
silkscreen for one, though.
I have sound through a USB sound card and no internal speaker at all
(with or without a pigtail- I looked), but when I boot up, I get the POST
beeps from somewhere inside the PC (no power to the sound system at that
time). I'll have to pull the side of the case the next time I reboot to
see where it's coming from, but there's no obvious spot. It's a small to
mid tower (Compaq SR1124nx) that I've had for years, and it's the only
factory thing left. Everything in it has been replaced at one time or
another, and I am yet to find a speaker :-) That's why I assumed the
beeps were coming from the MB.


The computer cases I have here, they like to hide the speaker in the
front plastic fascia. If you take the thing all apart, eventually you
might be rewarded with a 2" speaker or the like.

If you trace where the SPKR connector and two wire cable go,
you'll eventually find it. It can't escape :-) Start at the
motherboard PANEL header, and work your way back, following
the two wire twisted pair.

Paul


Well, gawrsh, now I REALly feel foolish (hangs head, donkey ears grow). I
have no speaker (or wires either- the MB pins are empty), and nothing on the
board, either. The beeps I hear on boot up are from my UPS- I use it like a
power strip to turn everything on and off. It's to the rear of my PC, and
the beeps it emits sound like they're coming from the PC case. sigh
--
SC Tom

  #21  
Old May 9th 11, 08:45 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

SC Tom,

We've all made those mistakes...............Now get your head round this....

Last thought was perhaps PSU is after all faulty. Thinks......Somehow fires
up fans and fan lights come on but other wise does nothing. Fortunately
have spare so replaced. Note: new PSU tested and voltage measured off board
by shorting pins14 (Power Supply On) to Ground (COM). All Good.

Install main board molex connectors. Do not connect power to DVD's. Press
ON button ----- nothing ??? Old PSU starts fans/lights when ON button
pressed (?) . What's happening (?) Remove 20 pin molex, short pin 14 to
ground fans start and fan lights come on. Now my understanding is pin 14
(power supply on) is only active (low) when PSU receives motherboard OK
signal

Why should one PSU 'fire' up when ON is pressed and the other not??. Do I
have a faulty motherboard ?? I suspect I have but.......... some rational
behind what's happening with PSU's is welcome


"SC Tom" wrote in message ...

"Paul" wrote in message
...
SC Tom wrote:


*** You're correct on that; my old OEM board had the piezo device on it,
but my new (to me) M2NPV-VM doesn't. It has the solder points and
silkscreen for one, though.
I have sound through a USB sound card and no internal speaker at all
(with or without a pigtail- I looked), but when I boot up, I get the
POST beeps from somewhere inside the PC (no power to the sound system at
that time). I'll have to pull the side of the case the next time I
reboot to see where it's coming from, but there's no obvious spot. It's
a small to mid tower (Compaq SR1124nx) that I've had for years, and it's
the only factory thing left. Everything in it has been replaced at one
time or another, and I am yet to find a speaker :-) That's why I assumed
the beeps were coming from the MB.


The computer cases I have here, they like to hide the speaker in the
front plastic fascia. If you take the thing all apart, eventually you
might be rewarded with a 2" speaker or the like.

If you trace where the SPKR connector and two wire cable go,
you'll eventually find it. It can't escape :-) Start at the
motherboard PANEL header, and work your way back, following
the two wire twisted pair.

Paul


Well, gawrsh, now I REALly feel foolish (hangs head, donkey ears grow). I
have no speaker (or wires either- the MB pins are empty), and nothing on
the board, either. The beeps I hear on boot up are from my UPS- I use it
like a power strip to turn everything on and off. It's to the rear of my
PC, and the beeps it emits sound like they're coming from the PC case.
sigh
--
SC Tom

  #22  
Old May 9th 11, 10:43 PM posted to microsoft.public.windowsxp.hardware
Paul
external usenet poster
 
Posts: 18,275
Default PC no longer booting

barrowhill wrote:
SC Tom,

We've all made those mistakes...............Now get your head round
this....

Last thought was perhaps PSU is after all faulty. Thinks......Somehow
fires up fans and fan lights come on but other wise does nothing.
Fortunately have spare so replaced. Note: new PSU tested and voltage
measured off board by shorting pins14 (Power Supply On) to Ground
(COM). All Good.

Install main board molex connectors. Do not connect power to DVD's.
Press ON button ----- nothing ??? Old PSU starts fans/lights when ON
button pressed (?) . What's happening (?) Remove 20 pin molex, short pin
14 to ground fans start and fan lights come on. Now my understanding is
pin 14 (power supply on) is only active (low) when PSU receives
motherboard OK signal

Why should one PSU 'fire' up when ON is pressed and the other not??. Do
I have a faulty motherboard ?? I suspect I have but.......... some
rational behind what's happening with PSU's is welcome


I would start by checking whether you still had data cables connected
from the DVD. If you're going to disconnect a drive, it would be
better to disconnect both power and data. A data connector can be left
connected if an I/O pad is known as "failsafe", but we don't know whether
that is the case or not. So when the characteristics of a device are
unknown, it is best to disconnect both data and power to it at the same
time, just in case.

The motherboard has an open collector driver, to pull to ground the
PS_ON# signal (pin 14). The power supply end has a pullup, and it is weak and
easy for PS_ON# to overcome and pull to ground. A logic low level,
is what triggers the power supply into the ON state.

The front panel POWER button (soft power), gives a momentary low pulse
at logic levels. The front power button doesn't actually gate the
flow of power directly. It sends a logic signal to the motherboard.
The motherboard "latches" the front panel signal and converts in into
a steady level.

The motherboard logic has many inputs into that circuit.

1) The Southbridge and SuperI/O have a number of "Wake On" conditions,
that they accept and use to turn on the computer when you want to
wake it up. For example, if you enable "Wake On LAN" on your system,
when a LAN packet arrives, it asserts PME, which is then used to
(eventually) turn on PS_ON#.

2) Certain safety features on the motherboard, work in the opposite
sense. Modern motherboards (both AMD and Intel) have THERMTRIP.
If the processor asserts THERMTRIP during an overheat event,
the motherboard logic de-asserts PS_ON# immediately, and that
causes the power supply to go off.

Some of those safety features are "latching", and you must turn off
the main power switch on the back of the computer, before your next
attempt to turn on the computer again via the front (soft) power switch.

On some older Asus motherboards, the "AGP Warn" circuit did something
similar. It prevented power from coming on, when a 3.3V only video
card was inserted into a 1.5V only motherboard AGP slot. That would
not be a concern on a PCI Express motherboard.

When your system refuses to respond, you can see there are a couple kinds
of logic inputs, that are presented to the motherboard. There can also
be situations where "accidental" things happen. For example, on my old
440BX motherboard, if the IDE connector was installed crooked (only
half the pins touching), the resulting electrical stress on the
Southbridge would cause the power to come on, on its own, without
touching the button on the front of the computer.

On some motherboards, if the CMOS battery is flat, and reads zero volts
with a multimeter, that can prevent PS_ON# from working. A possible
theory is, it happens at the SuperI/O chip, as it can have a connection
directly to the CMOS battery. And in that case, perhaps the SuperI/O isn't
passing a logic signal from somewhere else on the motherboard, until
the battery is replaced.

The chip driving PS_ON# can become weak. Or, the power supply end
can do a poor job of dealing with the logic level on the PS_ON#
signal. The power supply doesn't use a logic chip, but can use a
discrete transistor circuit for the job.

The system is relatively complicated (and really deserves a better
treatment than I can give it).

The circuitry of this type, might be referred to as "Supervisory"
circuitry. On the motherboard, the +5VSB rail from the power supply,
powers the Supervisory circuits. If your power supply has a weak
or glitchy +5VSB, then that can cause problems turning on the computer.
On an Asus motherboard, they put a green LED on the motherboard wired
directly to +5VSB. On such a motherboard, you visually check that LED,
to make sure it remains lit as long as the switch on the back of the
computer is in the ON position. If that supply rail is overloaded
(+5VSB has a weak rating in amperes), the LED can go on and off rapidly,
or blink. And that would tell you that between the motherboard and
the power supply, something is happening to the ability to maintain
a steady 5V on the +5VSB (StandBy) rail. A weak supply can do that,
as could a short on +5VSB from say, a USB load or PS/2 load.

Paul



"SC Tom" wrote in message ...

"Paul" wrote in message
...
SC Tom wrote:


*** You're correct on that; my old OEM board had the piezo device on
it, but my new (to me) M2NPV-VM doesn't. It has the solder points
and silkscreen for one, though.
I have sound through a USB sound card and no internal speaker at all
(with or without a pigtail- I looked), but when I boot up, I get the
POST beeps from somewhere inside the PC (no power to the sound
system at that time). I'll have to pull the side of the case the
next time I reboot to see where it's coming from, but there's no
obvious spot. It's a small to mid tower (Compaq SR1124nx) that I've
had for years, and it's the only factory thing left. Everything in
it has been replaced at one time or another, and I am yet to find a
speaker :-) That's why I assumed the beeps were coming from the MB.

The computer cases I have here, they like to hide the speaker in the
front plastic fascia. If you take the thing all apart, eventually you
might be rewarded with a 2" speaker or the like.

If you trace where the SPKR connector and two wire cable go,
you'll eventually find it. It can't escape :-) Start at the
motherboard PANEL header, and work your way back, following
the two wire twisted pair.

Paul


Well, gawrsh, now I REALly feel foolish (hangs head, donkey ears
grow). I have no speaker (or wires either- the MB pins are empty), and
nothing on the board, either. The beeps I hear on boot up are from my
UPS- I use it like a power strip to turn everything on and off. It's
to the rear of my PC, and the beeps it emits sound like they're coming
from the PC case. sigh
--
SC Tom

  #23  
Old May 10th 11, 10:18 AM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

Paul,

Thanks for this reply. Performed re-test using both PSU's having first
checked, off board, both working and all connectors showing correct
voltages. Tested both with data and power connectors to 2 x DVD connected,
then again with data and power connectors disconnected.
Original fitted PSU powers up (well fan and fan lights at least) when ON
button pressed in both test cases. Spare PSU doesn't !!! (again in both
cases)

I can't think of any reason why this is the case as both tested fine off
board.

I've run out of ideas now in trying to resolve original problem other than
coming to conclusion that the moth board is faulty.



  #24  
Old May 10th 11, 10:46 AM posted to microsoft.public.windowsxp.hardware
Paul
external usenet poster
 
Posts: 18,275
Default PC no longer booting

barrowhill wrote:
Paul,

Thanks for this reply. Performed re-test using both PSU's having first
checked, off board, both working and all connectors showing correct
voltages. Tested both with data and power connectors to 2 x DVD
connected, then again with data and power connectors disconnected.
Original fitted PSU powers up (well fan and fan lights at least) when ON
button pressed in both test cases. Spare PSU doesn't !!! (again in both
cases)

I can't think of any reason why this is the case as both tested fine
off board.

I've run out of ideas now in trying to resolve original problem other
than coming to conclusion that the moth board is faulty.


I hesitate to suggest this, but the PS_ON# signal can be activated,
while the main connector is connected to the motherboard. Since
PS_ON# is open collector, grounding it can turn on the supply and help
verify the rest of the motherboard is operational.

The problem with doing this, is it defeats safety systems on the
motherboard. For example, say your processor heatsink/fan fell of
the processor. On a normal computer, that would trigger THERMTRIP
(sent from processor to motherboard). The motherboard would
respond, by turning off PS_ON#. If you ground PS_ON# (effectively
jamming the setting in the ON position), then a THERMTRIP event
will not result in the power supply being turned off, and the processor
would be "cooked".

So using that test case, grounding PS_ON# while main power is connected,
can be used to verify the computer actually boots, but it does not
solve the problem of why the motherboard logic is not currently
driving the signal itself. As you say, it could be a defective
motherboard, but you also have to look at the circumstances, and
whether there were similar behaviors (difficult to get system
to turn on), before this happened.

*******

There are various versions of power supply standards, to help
you determine pinout on the cabling. While cable colors are
relatively standardized, I have at least one extension cable
here, that doesn't follow the rules on color. And when I'm using that
cable, I have to "count pins" to find the right signal.

http://web.archive.org/web/200304240...12V_PS_1_1.pdf (page 27)

http://www.formfactors.org/developer...X12V_1_3dg.pdf (page 30)

http://www.formfactors.org/developer...public_br2.pdf (page 37)

Paul

  #25  
Old May 10th 11, 03:54 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

Paul,

Again thanks for the useful information.

I had thought about forcing /PS-ON but decided against doing this for
reasons you mention. As you concur, the motherboard could be a defective,
and, as you say, one needs to look at the circumstances, and whether there
were similar behaviors' (difficult to get system to turn on), before this
happened.

On this point, there was a problem with the USB KB and mouse (reason why I
was looking at PC). I'd got PC working (and updated) by virtue of using
PS/2 KB and mouse. As stated earlier, all working fine when switched off.
Having started up the following day, not with PS/2 KB and mouse attached but
with USB ones I got an immediate unrecoverable hardware error. I believe
this is the crux of the problem. I think connecting the USB devices tip the
scales on a pre existing problem and has finally zeroes the motherboard.

I think all avenues have been exhausted and a new motherboard (or PC) is
required. Thanks for your (and others) input on this. Much appreciated.


"Paul" wrote in message
...
barrowhill wrote:
Paul,

Thanks for this reply. Performed re-test using both PSU's having first
checked, off board, both working and all connectors showing correct
voltages. Tested both with data and power connectors to 2 x DVD
connected, then again with data and power connectors disconnected.
Original fitted PSU powers up (well fan and fan lights at least) when ON
button pressed in both test cases. Spare PSU doesn't !!! (again in both
cases)

I can't think of any reason why this is the case as both tested fine off
board.

I've run out of ideas now in trying to resolve original problem other
than coming to conclusion that the moth board is faulty.


I hesitate to suggest this, but the PS_ON# signal can be activated,
while the main connector is connected to the motherboard. Since
PS_ON# is open collector, grounding it can turn on the supply and help
verify the rest of the motherboard is operational.

The problem with doing this, is it defeats safety systems on the
motherboard. For example, say your processor heatsink/fan fell of
the processor. On a normal computer, that would trigger THERMTRIP
(sent from processor to motherboard). The motherboard would
respond, by turning off PS_ON#. If you ground PS_ON# (effectively
jamming the setting in the ON position), then a THERMTRIP event
will not result in the power supply being turned off, and the processor
would be "cooked".

So using that test case, grounding PS_ON# while main power is connected,
can be used to verify the computer actually boots, but it does not
solve the problem of why the motherboard logic is not currently
driving the signal itself. As you say, it could be a defective
motherboard, but you also have to look at the circumstances, and
whether there were similar behaviors (difficult to get system
to turn on), before this happened.

*******

There are various versions of power supply standards, to help
you determine pinout on the cabling. While cable colors are
relatively standardized, I have at least one extension cable
here, that doesn't follow the rules on color. And when I'm using that
cable, I have to "count pins" to find the right signal.

http://web.archive.org/web/200304240...12V_PS_1_1.pdf
(page 27)

http://www.formfactors.org/developer...X12V_1_3dg.pdf (page 30)

http://www.formfactors.org/developer...public_br2.pdf
(page 37)

Paul

  #26  
Old May 10th 11, 04:11 PM posted to microsoft.public.windowsxp.hardware
SC Tom[_3_]
external usenet poster
 
Posts: 4,089
Default PC no longer booting

Do you by chance have another USB keyboard and mouse you can connect to the
faulty PC? Or have you tried that keyboard and mouse on a different PC?
Maybe it's one of them that's causing the issue, and not necessarily the
mobo (although I'm leaning towards a faulty mobo).
--
SC Tom

"barrowhill" wrote in message
...
Paul,

Again thanks for the useful information.

I had thought about forcing /PS-ON but decided against doing this for
reasons you mention. As you concur, the motherboard could be a defective,
and, as you say, one needs to look at the circumstances, and whether there
were similar behaviors' (difficult to get system to turn on), before this
happened.

On this point, there was a problem with the USB KB and mouse (reason why I
was looking at PC). I'd got PC working (and updated) by virtue of using
PS/2 KB and mouse. As stated earlier, all working fine when switched off.
Having started up the following day, not with PS/2 KB and mouse attached
but with USB ones I got an immediate unrecoverable hardware error. I
believe this is the crux of the problem. I think connecting the USB
devices tip the scales on a pre existing problem and has finally zeroes
the motherboard.

I think all avenues have been exhausted and a new motherboard (or PC) is
required. Thanks for your (and others) input on this. Much appreciated.


"Paul" wrote in message
...
barrowhill wrote:
Paul,

Thanks for this reply. Performed re-test using both PSU's having first
checked, off board, both working and all connectors showing correct
voltages. Tested both with data and power connectors to 2 x DVD
connected, then again with data and power connectors disconnected.
Original fitted PSU powers up (well fan and fan lights at least) when ON
button pressed in both test cases. Spare PSU doesn't !!! (again in both
cases)

I can't think of any reason why this is the case as both tested fine
off board.

I've run out of ideas now in trying to resolve original problem other
than coming to conclusion that the moth board is faulty.


I hesitate to suggest this, but the PS_ON# signal can be activated,
while the main connector is connected to the motherboard. Since
PS_ON# is open collector, grounding it can turn on the supply and help
verify the rest of the motherboard is operational.

The problem with doing this, is it defeats safety systems on the
motherboard. For example, say your processor heatsink/fan fell of
the processor. On a normal computer, that would trigger THERMTRIP
(sent from processor to motherboard). The motherboard would
respond, by turning off PS_ON#. If you ground PS_ON# (effectively
jamming the setting in the ON position), then a THERMTRIP event
will not result in the power supply being turned off, and the processor
would be "cooked".

So using that test case, grounding PS_ON# while main power is connected,
can be used to verify the computer actually boots, but it does not
solve the problem of why the motherboard logic is not currently
driving the signal itself. As you say, it could be a defective
motherboard, but you also have to look at the circumstances, and
whether there were similar behaviors (difficult to get system
to turn on), before this happened.

*******

There are various versions of power supply standards, to help
you determine pinout on the cabling. While cable colors are
relatively standardized, I have at least one extension cable
here, that doesn't follow the rules on color. And when I'm using that
cable, I have to "count pins" to find the right signal.

http://web.archive.org/web/200304240...12V_PS_1_1.pdf
(page 27)

http://www.formfactors.org/developer...X12V_1_3dg.pdf (page
30)

http://www.formfactors.org/developer...public_br2.pdf
(page 37)

Paul


  #27  
Old May 10th 11, 04:38 PM posted to microsoft.public.windowsxp.hardware
barrowhill
external usenet poster
 
Posts: 46
Default PC no longer booting

SC Tom

USB KB and mouse are from my on PC. Both working fine on my machine


"SC Tom" wrote in message ...

Do you by chance have another USB keyboard and mouse you can connect to
the faulty PC? Or have you tried that keyboard and mouse on a different
PC? Maybe it's one of them that's causing the issue, and not necessarily
the mobo (although I'm leaning towards a faulty mobo).
--
SC Tom





 




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