PC has no video and no beep code??

  • Thread starter Thread starter Roy Mottola
  • Start date Start date
VanguardLH said:
I don't recall seeing if you have already checked the *loaded* voltages
from the PSU. With the PSU connected to the motherboard, possibly the
video card (if it has a 12V connector), at least one hard disk (the one
with the OS partition), are the voltages on the 12V and 5V lines within
specs when you check with a multimeter?
Click to expand...

I'm not even sure what the voltages should be on the different pins. I also
don't trust that a voltage reading without a load connected will be accurate
when the load is applied, so I just swapped the PSU and still got no beep
 
You sure you have an Asus P4C800ED motherboard? It isn't listed at
http://usa.asus.com/Motherboards/AllProducts/. The closest I can get is
their P4P800-E Deluxe. Did I guess correctly?

If this is a really old model, might it have been produced during the
era when a bad electrolyte formulae were used for capacitors? See
http://en.wikipedia.org/wiki/Capacitor_plague. If you see electrolytic
caps with bulging tops or sides, or see electrolyte that has oozed out,
or discoloration around the cap on the motherboard, you have bad caps.
There are shops that will replace the bad caps but the cost is probably
more than the motherboard is worth.

I didn't see (or recall) mention that you tried a different monitor.
That the monitor is black doesn't mean the system isn't booting or that
Windows isn't loading. With the monitor powered off, you can usually
tell that the system got past the POST screen and is loading the OS by
the noise that the hard disk makes as its heads thrash around seeking
the clusters to load files into memory.

Do you have an internal speaker and, if so, is it connected to the
motherboard SPKR header? If there's an internal speaker, it came with
the system case, not with the motherboard. Are you instead relying on
beeps to emanate out of external speakers, like those connected to the
line-out jack on your sound card or sound connectors on the
motherboard's backpanel or those in the monitor? From the online manual
at:

http://dlcdnet.asus.com/pub/ASUS/mb/sock478/P4P800-E DX/e1867_p4p800-e_deluxe.pdf
page 1-5
"The motherboard offers an exciting feature called the ASUS POST
Reporter to provide friendly voice messages and alerts during the Power-
On Self-Tests (POST). Through an added external speaker, you will hear
the messages informing you of the system boot status and causes of boot
errors, if any."

Looks like voice alerts get sent to the speaker instead of beeps. This
assumes that you haven't disabled the ASUS Speech POST Reporter in the
BIOS setup. It is enabled by default.

Were you overclocking anything? That can cause a host to hang when
adjustments are too far out-of-spec (and why some overclockable mobos
have a reset to undo any overclocking to get back to a usable state).

Have you yet tried to short the 2-pin header for CMOS Reset? If the
BIOS is corrupted, have invalid values, or you've been overclocking and
selected invalid or bad values, this will reset them to the factory
defaults. If this works, replace the CMOS battery (probably a CR2032)
since a weak battery can lead to a corrupted copy of the BIOS that gets
saved in the CMOS table. You can get CR2032 batteries pretty cheap at
eBay but be sure to ask the seller for the expiration date (they often
don't list it and usually don't even look). You want one with an
expiration date some 3-5 years out from now.
 
Mark said:
I've certainly experienced no beeps when it was just the video card
that was faulty.
Click to expand...

In which case, pulling the video card, pulling the RAM, and doing
a "beep test" and listening for the BIOS to issue a beep code to
the computer case speaker, is an easy test to tell you whether
the CPU and motherboard are still working.

Asus motherboards of that era, also have "Vocal POST". Connect
amplified computer speakers, to the green "LineOut" connector
on the I/O plate audio, to listen for it. When the computer starts,
you may get an audible error message from that. (Whether it is
enabled, is set in the BIOS screens, and I don't know under
what circumstances it can be completely turned off. None of the
CMOS settings should be able to do anything, if your processor
is dead...)

The vocal message "No CPU Installed", is determined by the grounding
of a certain pin in the CPU socket.

The messages "System Failed CPU Test" and "System Failed RAM Test"
are based on timers in the Winbond chip, timing out when they
receive no response from the CPU. The Winbond Vocal Post chip
is autonomous, and can function all by itself, which is
why the messages can be delivered. The CPU has to "clear a timer"
on the chip, to stop the message from occurring.

You'd only use the Vocal Post option, if you'd run out of other
options, and were desperate for information. For example, if you
could not get any "beeps" from the computer case speaker (SPKR header
pins), then plugging in your amplified external computer speakers
and listening for Vocal Post messages, is your last (free) option.
The messages are pretty hard to hear, and it's best to keep a
printed copy of the manual handy, and match the "cadence" of the
noise you hear, to the length of the message :-)

Paul
 
Paul said:
In which case, pulling the video card, pulling the RAM, and doing
a "beep test" and listening for the BIOS to issue a beep code to
the computer case speaker, is an easy test to tell you whether
the CPU and motherboard are still working.
Click to expand...

As I recall, with no system RAM available on the mobo, there will be an
immediate beep without even waiting for the video BIOS to load; however,
this mobo has vocal error alerts but I don't know if they play through
the mobo-connected cheapie case speaker (or a piezo speaker soldered on
the mobo) or through the sound connectors in the backpanel from the
onboard audio controller. I have seen Dells where the beeps came out
the external powered speakers (there was no internal speaker): if the
external speakers weren't powered up, you couldn't hear the beeps.

I don't recall Roy (who then nymshifted into RBM) has looked to see if
the case speaker connected to a 4-pin SPKR header on the mobo (and
tested it to make sure it can make noise). If the internal speaker
isn't working, isn't connected, or comes out the backpanel audio
connectors to go to external speakers (and the external speakers are
powered off or muted), the whole issue of beeps might not be relevant to
his non-boot problem.

Question: If the CPU were defective, missing, or [partially]
disconnected, what is going to execute the firmware code in the BIOS?
It's machine code (a mini operating system) and something has to load
and execute it.

I just thought of something else (in case the computer is booting okay
but without audible beeps for another reason): I've seen LCD monitor get
switched to a different input port. That would make the LCD monitor
look black because there is no video signal on the currently selected
input port. The user has to play around with the monitor's buttons
trying to get it to switch between the various input ports: VGA, DVI,
and DPMI (if available). If the video cable is connected to the DVI
port but the VGA port is selected in the monitor then the monitor will
be black. Roy/RBM said he momentarily saw "no signal" so this isn't the
case of a user kicking out the power plug for the monitor when swinging
his legs under his desk and wondering why the monitor is black.
 
VanguardLH said:
As I recall, with no system RAM available on the mobo, there will be an
immediate beep without even waiting for the video BIOS to load; however,
this mobo has vocal error alerts but I don't know if they play through
the mobo-connected cheapie case speaker (or a piezo speaker soldered on
the mobo) or through the sound connectors in the backpanel from the
onboard audio controller. I have seen Dells where the beeps came out
the external powered speakers (there was no internal speaker): if the
external speakers weren't powered up, you couldn't hear the beeps.
Click to expand...

The "PC Beep" function is electrically separate from Vocal POST. They
don't use the same speaker.

The Winbond Vocal POST chip, is capacitively coupled into the
green LineOut connector on the motherboard. It looks like this
in terms of motherboard wiring.

PC_Beep --------------------- SPKR pin header (switching transistor drive)

AC'97 -------------+-------- Line Out (Lime green colored connector)
CODEC | (Motherboard audio stack)
capacitor
|
Vocal Post --------+

(PCI Sound Card) ------------- Line Out (green connector on PCI card)

You're right, that some computers choose to insert PC_Beep,
into the regular audio path. Lucky for me, all my computers
are like the above diagram.

If a person is using a separate PCI sound card, they can miss the Vocal
Post feature entirely. If you're using "motherboard sound" via the AC'97
CODEC, then you may get to hear the Vocal Post prompts. An annoying one,
is "now booting operating system" or the like, played at a healthy volume.
On my P4C800-E Deluxe, I had a separate $10 sound card, so never heard
any Vocal Post while using it. (Moving the speaker plug to the
other connector, would give easy access to it.) The BIOS setup screen
on later Asus motherboards, includes two settings to control the
more annoying messages, so it's possible to turn off the boot message.
Vocal Post was only shipped for around three years or so, and after
that Asus stopped including the chip in new designs.

The PC_Beep will not be generated, if the processor can't reach
through the Northbridge and Southbridge and read some BIOS code.
A PC generates a single beep sound, as the equivalent of a "lamp test
function", to prove the computer case speaker works. But there have
been the odd Asus motherboard, where in fact the beep is broken. The
reason it broke, was another code fix they did. Once upon a time,
Asus would "beep" for each detected USB peripheral device. This
made users very angry, and Asus rushed out a fix to stop it. Their fix ?
To disable the path to PC Beep :-) So rather than just comment out
the code in the USB module, they cut off virtually everything.
I presume that meant only changing one code module. Lazy bastards.
I don't recall Roy (who then nymshifted into RBM) has looked to see if
the case speaker connected to a 4-pin SPKR header on the mobo (and
tested it to make sure it can make noise). If the internal speaker
isn't working, isn't connected, or comes out the backpanel audio
connectors to go to external speakers (and the external speakers are
powered off or muted), the whole issue of beeps might not be relevant to
his non-boot problem.

Question: If the CPU were defective, missing, or [partially]
disconnected, what is going to execute the firmware code in the BIOS?
It's machine code (a mini operating system) and something has to load
and execute it.
Click to expand...

If you unplug video card and system RAM modules, the BIOS code can still
execute. But the processor has to get to the BIOS code for that to happen.
The BIOS code also has access to the PC_Beep. The code doesn't rely
on system RAM, and it's possible for the processor to run register based
code, until commissioning of the Northbridge is complete (memory map
and DIMM parameters are set up).
I just thought of something else (in case the computer is booting okay
but without audible beeps for another reason): I've seen LCD monitor get
switched to a different input port. That would make the LCD monitor
look black because there is no video signal on the currently selected
input port. The user has to play around with the monitor's buttons
trying to get it to switch between the various input ports: VGA, DVI,
and DPMI (if available). If the video cable is connected to the DVI
port but the VGA port is selected in the monitor then the monitor will
be black. Roy/RBM said he momentarily saw "no signal" so this isn't the
case of a user kicking out the power plug for the monitor when swinging
his legs under his desk and wondering why the monitor is black.
Click to expand...

But ignoring those symptoms for a moment, we should be able to get a
beep test going, if the motherboard isn't a vegetable. Without
video card or RAM installed, there should be a repeating two beep or
three beep pattern coming from the computer case speaker (PC_Beep).
If that works, and there are beeps, next you insert RAM, and see if
the beeps stop. If they stop, replace RAM. IF the beep pattern is
maintained, but the pattern changes (one more or one less beep in
pattern), now the motherboard is looking for the next item, which
is the video card. If inserting the video card stops the beeps,
then the video card is bad. Quite a bit of testing can be done with
the beeps as guidance. If you pass all those steps, and there
is no joy in terms of starting up, a PCI Port 80 card can be used
to find out why.

If there are zero beeps (and the user knows for a fact, that the
system normally beeps once), then the suspects would include

bad cpu
missing ATX12V power cable or bad power supply feeding it
bad Northbridge, Southbridge, BIOS chip contents
bad PC_Beep speaker, bad driver transistor
bad motherboard local power regulation functions (tied into Power_Good)

Since the board features the "known bad" ICH5/ICH5R Southbridge,
it's kinda easy for me to jump to the conclusion there will be
no beeps, and "she's a vegetable". Until some contrary evidence
shows up. If Roy hooks up the Vocal Post, clears CMOS with
power off, and the Vocal Post reports "System failed CPU test",
then that is a second confirmation that BIOS code is not
able to run. The BIOS code includes a call, to clear the timer
on the Winbond, before the "System failed CPU test" message
can start to play. If the CPU is dead in the water, then
the Vocal Post gets to play that voice message. If the user has
erased the Vocal Post serial EEPROM chip, using the available
software, then no voice will be present. Otherwise, you could
get some message from the Vocal thing.

Paul
 
VanguardLH said:
As I recall, with no system RAM available on the mobo, there will be an
immediate beep without even waiting for the video BIOS to load; however,
this mobo has vocal error alerts but I don't know if they play through
the mobo-connected cheapie case speaker (or a piezo speaker soldered on
the mobo) or through the sound connectors in the backpanel from the
onboard audio controller. I have seen Dells where the beeps came out
the external powered speakers (there was no internal speaker): if the
external speakers weren't powered up, you couldn't hear the beeps.

I don't recall Roy (who then nymshifted into RBM) has looked to see if
the case speaker connected to a 4-pin SPKR header on the mobo (and
tested it to make sure it can make noise). If the internal speaker
isn't working, isn't connected, or comes out the backpanel audio
connectors to go to external speakers (and the external speakers are
powered off or muted), the whole issue of beeps might not be relevant to
his non-boot problem.
Click to expand...

** Sorry about the morph, I've used RBM for years, and just set it up wrong
on a temp PC.
The case speaker is connected and was working
Question: If the CPU were defective, missing, or [partially]
disconnected, what is going to execute the firmware code in the BIOS?
It's machine code (a mini operating system) and something has to load
and execute it.
Click to expand...

** I did replace the power supply ,video card (agp), and CPU, with no change
 
Paul said:
The "PC Beep" function is electrically separate from Vocal POST. They
don't use the same speaker.

The Winbond Vocal POST chip, is capacitively coupled into the
green LineOut connector on the motherboard. It looks like this
in terms of motherboard wiring.

PC_Beep --------------------- SPKR pin header (switching
transistor drive)

AC'97 -------------+-------- Line Out (Lime green colored
connector)
CODEC | (Motherboard audio stack)
capacitor
|
Vocal Post --------+

(PCI Sound Card) ------------- Line Out (green connector on PCI
card)

You're right, that some computers choose to insert PC_Beep,
into the regular audio path. Lucky for me, all my computers
are like the above diagram.

If a person is using a separate PCI sound card, they can miss the Vocal
Post feature entirely. If you're using "motherboard sound" via the AC'97
CODEC, then you may get to hear the Vocal Post prompts. An annoying one,
is "now booting operating system" or the like, played at a healthy volume.
On my P4C800-E Deluxe, I had a separate $10 sound card, so never heard
any Vocal Post while using it. (Moving the speaker plug to the
other connector, would give easy access to it.) The BIOS setup screen
on later Asus motherboards, includes two settings to control the
more annoying messages, so it's possible to turn off the boot message.
Vocal Post was only shipped for around three years or so, and after
that Asus stopped including the chip in new designs.
Click to expand...


** This board has "speech post reporting" as a setting in the bios, which
can be enabled or disabled. It was so annoying, I've always had it disabled
The PC_Beep will not be generated, if the processor can't reach
through the Northbridge and Southbridge and read some BIOS code.
A PC generates a single beep sound, as the equivalent of a "lamp test
function", to prove the computer case speaker works. But there have
been the odd Asus motherboard, where in fact the beep is broken. The
reason it broke, was another code fix they did. Once upon a time,
Asus would "beep" for each detected USB peripheral device. This
made users very angry, and Asus rushed out a fix to stop it. Their fix ?
To disable the path to PC Beep :-) So rather than just comment out
the code in the USB module, they cut off virtually everything.
I presume that meant only changing one code module. Lazy bastards.
I don't recall Roy (who then nymshifted into RBM) has looked to see if
the case speaker connected to a 4-pin SPKR header on the mobo (and
tested it to make sure it can make noise). If the internal speaker
isn't working, isn't connected, or comes out the backpanel audio
connectors to go to external speakers (and the external speakers are
powered off or muted), the whole issue of beeps might not be relevant to
his non-boot problem.

Question: If the CPU were defective, missing, or [partially]
disconnected, what is going to execute the firmware code in the BIOS?
It's machine code (a mini operating system) and something has to load
and execute it.
Click to expand...

If you unplug video card and system RAM modules, the BIOS code can still
execute. But the processor has to get to the BIOS code for that to happen.
The BIOS code also has access to the PC_Beep. The code doesn't rely
on system RAM, and it's possible for the processor to run register based
code, until commissioning of the Northbridge is complete (memory map
and DIMM parameters are set up).
I just thought of something else (in case the computer is booting okay
but without audible beeps for another reason): I've seen LCD monitor get
switched to a different input port. That would make the LCD monitor
look black because there is no video signal on the currently selected
input port. The user has to play around with the monitor's buttons
trying to get it to switch between the various input ports: VGA, DVI,
and DPMI (if available). If the video cable is connected to the DVI
port but the VGA port is selected in the monitor then the monitor will
be black. Roy/RBM said he momentarily saw "no signal" so this isn't the
case of a user kicking out the power plug for the monitor when swinging
his legs under his desk and wondering why the monitor is black.
Click to expand...

But ignoring those symptoms for a moment, we should be able to get a
beep test going, if the motherboard isn't a vegetable. Without
video card or RAM installed, there should be a repeating two beep or
three beep pattern coming from the computer case speaker (PC_Beep).
If that works, and there are beeps, next you insert RAM, and see if
the beeps stop. If they stop, replace RAM. IF the beep pattern is
maintained, but the pattern changes (one more or one less beep in
pattern), now the motherboard is looking for the next item, which
is the video card. If inserting the video card stops the beeps,
then the video card is bad. Quite a bit of testing can be done with
the beeps as guidance. If you pass all those steps, and there
is no joy in terms of starting up, a PCI Port 80 card can be used
to find out why.

If there are zero beeps (and the user knows for a fact, that the
system normally beeps once), then the suspects would include

bad cpu
missing ATX12V power cable or bad power supply feeding it
bad Northbridge, Southbridge, BIOS chip contents
bad PC_Beep speaker, bad driver transistor
bad motherboard local power regulation functions (tied into
Power_Good)

Since the board features the "known bad" ICH5/ICH5R Southbridge,
it's kinda easy for me to jump to the conclusion there will be
no beeps, and "she's a vegetable". Until some contrary evidence
shows up. If Roy hooks up the Vocal Post, clears CMOS with
power off, and the Vocal Post reports "System failed CPU test",
then that is a second confirmation that BIOS code is not
able to run. The BIOS code includes a call, to clear the timer
on the Winbond, before the "System failed CPU test" message
can start to play. If the CPU is dead in the water, then
the Vocal Post gets to play that voice message. If the user has
erased the Vocal Post serial EEPROM chip, using the available
software, then no voice will be present. Otherwise, you could
get some message from the Vocal thing.

Paul
Click to expand...
 
RBM said:
** This board has "speech post reporting" as a setting in the bios, which
can be enabled or disabled. It was so annoying, I've always had it disabled
Click to expand...

But it is enabled by default in the BIOS. If the CMOS battery is weak
or dead, could be your BIOS settings are corrupt or have been reset.

If you have the P4P800E Deluxe that I could find (your P4C800ED wasn't
listed at the ASUS site), its manual at:

http://dlcdnet.asus.com/pub/ASUS/mb/sock478/P4P800-E DX/e1867_p4p800-e_deluxe.pdf

says the default is enabled for Speech Post Reporter. If the BIOS got
reset then you're back to that annoying vocal error reporting that comes
out the line-out jack instead of the internal speaker for beeps.
 
Back
Top