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Post problem with Z77H2-A3 motherboard



 
 
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  #1  
Old April 1st 20, 05:40 PM posted to alt.comp.hardware.pc-homebuilt
Bob F
external usenet poster
 
Posts: 153
Default Post problem with Z77H2-A3 motherboard

My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?
  #2  
Old April 1st 20, 06:55 PM posted to alt.comp.hardware.pc-homebuilt
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default Post problem with Z77H2-A3 motherboard

Bob F wrote:

My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?


The first and cheapest fix that I'd try is replaced the CMOS battery.
Afterward, clear the table in CMOS to force it to retrieve a fresh copy
from the EEPROM since what is in the table might be corrupt.

Its manual doesn't say what type of battery is used to keep power to the
RTC chip (with the CMOS table), but the mobo diagram shows a round
battery. That is likely a CR-2032 coin cell battery.
  #3  
Old April 1st 20, 07:05 PM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
external usenet poster
 
Posts: 1,467
Default Post problem with Z77H2-A3 motherboard

Bob F wrote:
My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?


1) Mostly a waste of time, but a PCI port 80 card or similar,
could show you some "progress codes". But if the Port 80
card only shows "FF" or "00", then the CPU isn't getting
a chance to execute any code. If you happen to own a PCI port 80
card, then use it. But don't waste your time and money tracking
one down. A local computer store might charge $100, for an
item worth $10 to $15 or so.

2) At a guess, Power_Good (from the PSU) is deasserting,
just after the RESET pulse finishes. And this will eventually
result in another RESET pulse being generated (looping behavior).

When the system comes up, measure the current flows on the main
ATX power cable with a clamp-on DC ammeter. What you're looking
for, is loading which is out of normal. With the "modern" power
supplies with the all-black wiring and sleeving that prevents
access to individual conductors, this is "difficult to impossible".
Thanks to "progress", we're denied a valuable debug input.

A "proxy" for overloads, is to measure the 3.3V, 5V, 12V voltages.
As those have the main DC loads. You might also check the -12V and
the +5VSB for the sake of completeness.

When using voltages as a proxy, we're looking for crossloading
effects. The short and sweet is, if one of the rails is
"abnormally low", suspect it's the one drawing too much current.

For example, the supply might have +/-5% tolerances. If one rail
is 1% below nominal, and the other rails are higher by 1%, that
hints that the below-normal one is up to something.

Each generation of computer, has a different loading pattern
for rails. The best time to establish norms, is to measure
the rails when the system is working. Or, if you have two
different manufacturers of systems in the same generation
of that hardware, compare the readings to see what typical
practice is.

My old Nforce2 board, a board which doesn't use +12V for the
processor, the +5V rail has a loading of 25 amps while gaming.
This would "tip over" almost all the supplies in the
current Newegg catalog.

Modern systems don't do that. You might expect 3.3V @ 6A or
5V @ 6A for deriving chipset voltages. These are moderate
loads compared to the PSU 3.3V @ 20A and 5V @ 20A capability.
Each hard drive, draws 1A from 5V. The optical drive can
draw a bit more than that.

The Power_Good signal from the PSU, is not the end of the
story in terms of the Power_Good concept. The purpose of
Power_Good, is to assure that the voltages are stable,
after the 35 millisecond capacitive load charge-up phase.
Hard drives, for example, won't start to spin until the
12V is a hair over 11V and rising. The hard drive, in a
sense, has its own private copy of Power_Good, which guides
its operation and loading characteristic. It doesn't
get to look at the ATX Power_Good for advice.

Some motherboard designs, use a Wired-OR of the PSU Power_Good,
plus a "good" indicator coming from various switching converters
on the motherboard.

As an example of an anomaly encountered years ago, two
brands of products would not "play nice" with one another.
An Antec supply, was "slow" raising its rail voltages. The
capacitive charging phase seemed to be slower than normal.
Then, you would combine that with a motherboard which had
OCP on VCore. The VCore converter would start converting
the 12V, before it was fully up. As the voltage drops on
input to a switcher, the current rises. The switcher
in a sense, is a "constant power" device. If the voltage
into the switcher drops by half, the current flow doubles.
Anyway, the VCore, upon starting its job based on some
timer, it sees maybe 6V on the 12V rail, thinks there is
an overload, and it "latches off". The customer motherboard
will not start. By switching off the power supply, the
latched status gets cleared, but the same thing will happen
on a second attempt. The solution is to mix different brands
of power supplies and motherboards, to avoid the "problem pair".

Your system, by looping like it is, is telling us that
no latching behavior coming from the motherboard is involved.
As that would stop the loop in a "failed state".

Yours keeps trying. That suggests, mainly, a problem
between the supply and the motherboard. Motherboard
is treating power supply "poorly". Bitch-slapping it.

This suggests some sort of issue with Power_Good, and
about all I can suggest is something is amiss with loading
which is ****ing off the power supply. Maybe it's the
"transient" of the VCore starting up with the full 12V
present.

There is a limit to how much capacitance can be on the
DC rails powered by your ATX supply. It's about 5000uF
per rail. The PSU has internal caps that account for
a fraction of that. The motherboard has bulk capacitors
for filtering too. The sum total on a particular rail,
should not exceed 5000uF to maintain sufficient phase
margin on the ATX control loop. While it would be
tempting to (as a hobbyist) suggest "adding more
capacitance", you have to be aware that these designs
only have 45 degrees of phase margin, up to a certain level.
And that spec (knowing how power supplies behave),
is hard to get. Even for an engineer, if I phone up
some fly-by-night operation in China, I would have a
hard time getting a definitive statement on that. The
above is simply a suggestion of a typical scenario.

If you had a pulse-catcher, you'd arm it right after
pushing the front panel power button, then see if it
catches a low-going transition on Power_Good. That would
be an indication that a "slug-of-current" was being drawn
by the motherboard. Such analysis is easy to do...
if we're back in the lab with our $35K storage scope :-)

My clamp-on ammeter can record the "peak" current in an
interval of time, and my voltmeter has both peak voltage
and lowest voltage detection. But these capabilities are
related to the sampling rate of the devices, and the
event we're looking for, is too short to catch
with these capabilities in measurement devices.
Even an HP meter with a 1KHz sampling rate and
peak detection, might miss what we're trying to see.

A storage scope wouldn't miss it.

*******

A second question for you might be, have you recently
changed the video card ? Try putting the old one back
as a test. Or even, pull the video card, and see if
the system enters the "missing video beep state"
properly. This would then indicate that the system
has survived the power up transient and the BIOS
code is getting to run. If the looping behavior continues,
with the (high power or new-ish) video card removed, then
you're no closer to an answer (it's not the video card
or the BIOS code that loads the video config space ROM).

Paul
  #4  
Old April 1st 20, 09:32 PM posted to alt.comp.hardware.pc-homebuilt
Bob F
external usenet poster
 
Posts: 153
Default Post problem with Z77H2-A3 motherboard

On 4/1/2020 10:55 AM, VanguardLH wrote:
Bob F wrote:

My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?


The first and cheapest fix that I'd try is replaced the CMOS battery.
Afterward, clear the table in CMOS to force it to retrieve a fresh copy
from the EEPROM since what is in the table might be corrupt.

Its manual doesn't say what type of battery is used to keep power to the
RTC chip (with the CMOS table), but the mobo diagram shows a round
battery. That is likely a CR-2032 coin cell battery.


Thanks. I have checked the battery and reset the CMOS multiple time.
  #5  
Old April 1st 20, 09:48 PM posted to alt.comp.hardware.pc-homebuilt
Bob F
external usenet poster
 
Posts: 153
Default Post problem with Z77H2-A3 motherboard

On 4/1/2020 11:05 AM, Paul wrote:
Bob F wrote:
My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked
fine for years, then started having occasional problems when turned
on, it would not post occasionally. The problem got more frequent over
months, until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour
of turning the power supply on, pushing the power switch, watching it
spin the fan for 2 seconds, stopping, then powering the fan for a
second, stopping, then powering the fan for a second......Â* When it
does actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test
for 40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the
power supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this
kind of problem, or point me to any references that might educate me
on the related circuitry?


1) Mostly a waste of time, but a PCI port 80 card or similar,
Â*Â* could show you some "progress codes". But if the Port 80
Â*Â* card only shows "FF" or "00", then the CPU isn't getting
Â*Â* a chance to execute any code. If you happen to own a PCI port 80
Â*Â* card, then use it. But don't waste your time and money tracking
Â*Â* one down. A local computer store might charge $100, for an
Â*Â* item worth $10 to $15 or so.

2) At a guess, Power_Good (from the PSU) is deasserting,
Â*Â* just after the RESET pulse finishes. And this will eventually
Â*Â* result in another RESET pulse being generated (looping behavior).

When the system comes up, measure the current flows on the main
ATX power cable with a clamp-on DC ammeter. What you're looking
for, is loading which is out of normal. With the "modern" power
supplies with the all-black wiring and sleeving that prevents
access to individual conductors, this is "difficult to impossible".
Thanks to "progress", we're denied a valuable debug input.

A "proxy" for overloads, is to measure the 3.3V, 5V, 12V voltages.
As those have the main DC loads. You might also check the -12V and
the +5VSB for the sake of completeness.

When using voltages as a proxy, we're looking for crossloading
effects. The short and sweet is, if one of the rails is
"abnormally low", suspect it's the one drawing too much current.

For example, the supply might have +/-5% tolerances. If one rail
is 1% below nominal, and the other rails are higher by 1%, that
hints that the below-normal one is up to something.

Each generation of computer, has a different loading pattern
for rails. The best time to establish norms, is to measure
the rails when the system is working. Or, if you have two
different manufacturers of systems in the same generation
of that hardware, compare the readings to see what typical
practice is.

My old Nforce2 board, a board which doesn't use +12V for the
processor, the +5V rail has a loading of 25 amps while gaming.
This would "tip over" almost all the supplies in the
current Newegg catalog.

Modern systems don't do that. You might expect 3.3V @ 6A or
5V @ 6A for deriving chipset voltages. These are moderate
loads compared to the PSU 3.3V @ 20A and 5V @ 20A capability.
Each hard drive, draws 1A from 5V. The optical drive can
draw a bit more than that.

The Power_Good signal from the PSU, is not the end of the
story in terms of the Power_Good concept. The purpose of
Power_Good, is to assure that the voltages are stable,
after the 35 millisecond capacitive load charge-up phase.
Hard drives, for example, won't start to spin until the
12V is a hair over 11V and rising. The hard drive, in a
sense, has its own private copy of Power_Good, which guides
its operation and loading characteristic. It doesn't
get to look at the ATX Power_Good for advice.

Some motherboard designs, use a Wired-OR of the PSU Power_Good,
plus a "good" indicator coming from various switching converters
on the motherboard.

As an example of an anomaly encountered years ago, two
brands of products would not "play nice" with one another.
An Antec supply, was "slow" raising its rail voltages. The
capacitive charging phase seemed to be slower than normal.
Then, you would combine that with a motherboard which had
OCP on VCore. The VCore converter would start converting
the 12V, before it was fully up. As the voltage drops on
input to a switcher, the current rises. The switcher
in a sense, is a "constant power" device. If the voltage
into the switcher drops by half, the current flow doubles.
Anyway, the VCore, upon starting its job based on some
timer, it sees maybe 6V on the 12V rail, thinks there is
an overload, and it "latches off". The customer motherboard
will not start. By switching off the power supply, the
latched status gets cleared, but the same thing will happen
on a second attempt. The solution is to mix different brands
of power supplies and motherboards, to avoid the "problem pair".

Your system, by looping like it is, is telling us that
no latching behavior coming from the motherboard is involved.
As that would stop the loop in a "failed state".

Yours keeps trying. That suggests, mainly, a problem
between the supply and the motherboard. Motherboard
is treating power supply "poorly". Bitch-slapping it.

This suggests some sort of issue with Power_Good, and
about all I can suggest is something is amiss with loading
which is ****ing off the power supply. Maybe it's the
"transient" of the VCore starting up with the full 12V
present.

There is a limit to how much capacitance can be on the
DC rails powered by your ATX supply. It's about 5000uF
per rail. The PSU has internal caps that account for
a fraction of that. The motherboard has bulk capacitors
for filtering too. The sum total on a particular rail,
should not exceed 5000uF to maintain sufficient phase
margin on the ATX control loop. While it would be
tempting to (as a hobbyist) suggest "adding more
capacitance", you have to be aware that these designs
only have 45 degrees of phase margin, up to a certain level.
And that spec (knowing how power supplies behave),
is hard to get. Even for an engineer, if I phone up
some fly-by-night operation in China, I would have a
hard time getting a definitive statement on that. The
above is simply a suggestion of a typical scenario.

If you had a pulse-catcher, you'd arm it right after
pushing the front panel power button, then see if it
catches a low-going transition on Power_Good. That would
be an indication that a "slug-of-current" was being drawn
by the motherboard. Such analysis is easy to do...
if we're back in the lab with our $35K storage scope :-)

My clamp-on ammeter can record the "peak" current in an
interval of time, and my voltmeter has both peak voltage
and lowest voltage detection. But these capabilities are
related to the sampling rate of the devices, and the
event we're looking for, is too short to catch
with these capabilities in measurement devices.
Even an HP meter with a 1KHz sampling rate and
peak detection, might miss what we're trying to see.

A storage scope wouldn't miss it.

*******

A second question for you might be, have you recently
changed the video card ? Try putting the old one back
as a test. Or even, pull the video card, and see if
the system enters the "missing video beep state"
properly. This would then indicate that the system
has survived the power up transient and the BIOS
code is getting to run. If the looping behavior continues,
with the (high power or new-ish) video card removed, then
you're no closer to an answer (it's not the video card
or the BIOS code that loads the video config space ROM).

Â*Â* Paul


Wow! You've given me a lot to think about. But I just found another clue
maybe.

It seems that moving the RAM SIMM from one slot to another or adding
another SIMM makes it boot the next time I start it. It still does an
on/off try first before it actually boots. I tried just popping it out
and back in the same slot, and that did not seem to do the same. This
is getting weird.

  #6  
Old April 1st 20, 10:16 PM posted to alt.comp.hardware.pc-homebuilt
Bob F
external usenet poster
 
Posts: 153
Default Post problem with Z77H2-A3 motherboard

On 4/1/2020 1:48 PM, Bob F wrote:
On 4/1/2020 11:05 AM, Paul wrote:
Bob F wrote:
My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked
fine for years, then started having occasional problems when turned
on, it would not post occasionally. The problem got more frequent
over months, until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour
of turning the power supply on, pushing the power switch, watching it
spin the fan for 2 seconds, stopping, then powering the fan for a
second, stopping, then powering the fan for a second......Â* When it
does actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test
for 40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the
power supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this
kind of problem, or point me to any references that might educate me
on the related circuitry?


1) Mostly a waste of time, but a PCI port 80 card or similar,
Â*Â*Â* could show you some "progress codes". But if the Port 80
Â*Â*Â* card only shows "FF" or "00", then the CPU isn't getting
Â*Â*Â* a chance to execute any code. If you happen to own a PCI port 80
Â*Â*Â* card, then use it. But don't waste your time and money tracking
Â*Â*Â* one down. A local computer store might charge $100, for an
Â*Â*Â* item worth $10 to $15 or so.

2) At a guess, Power_Good (from the PSU) is deasserting,
Â*Â*Â* just after the RESET pulse finishes. And this will eventually
Â*Â*Â* result in another RESET pulse being generated (looping behavior).

When the system comes up, measure the current flows on the main
ATX power cable with a clamp-on DC ammeter. What you're looking
for, is loading which is out of normal. With the "modern" power
supplies with the all-black wiring and sleeving that prevents
access to individual conductors, this is "difficult to impossible".
Thanks to "progress", we're denied a valuable debug input.

A "proxy" for overloads, is to measure the 3.3V, 5V, 12V voltages.
As those have the main DC loads. You might also check the -12V and
the +5VSB for the sake of completeness.

When using voltages as a proxy, we're looking for crossloading
effects. The short and sweet is, if one of the rails is
"abnormally low", suspect it's the one drawing too much current.

For example, the supply might have +/-5% tolerances. If one rail
is 1% below nominal, and the other rails are higher by 1%, that
hints that the below-normal one is up to something.

Each generation of computer, has a different loading pattern
for rails. The best time to establish norms, is to measure
the rails when the system is working. Or, if you have two
different manufacturers of systems in the same generation
of that hardware, compare the readings to see what typical
practice is.

My old Nforce2 board, a board which doesn't use +12V for the
processor, the +5V rail has a loading of 25 amps while gaming.
This would "tip over" almost all the supplies in the
current Newegg catalog.

Modern systems don't do that. You might expect 3.3V @ 6A or
5V @ 6A for deriving chipset voltages. These are moderate
loads compared to the PSU 3.3V @ 20A and 5V @ 20A capability.
Each hard drive, draws 1A from 5V. The optical drive can
draw a bit more than that.

The Power_Good signal from the PSU, is not the end of the
story in terms of the Power_Good concept. The purpose of
Power_Good, is to assure that the voltages are stable,
after the 35 millisecond capacitive load charge-up phase.
Hard drives, for example, won't start to spin until the
12V is a hair over 11V and rising. The hard drive, in a
sense, has its own private copy of Power_Good, which guides
its operation and loading characteristic. It doesn't
get to look at the ATX Power_Good for advice.

Some motherboard designs, use a Wired-OR of the PSU Power_Good,
plus a "good" indicator coming from various switching converters
on the motherboard.

As an example of an anomaly encountered years ago, two
brands of products would not "play nice" with one another.
An Antec supply, was "slow" raising its rail voltages. The
capacitive charging phase seemed to be slower than normal.
Then, you would combine that with a motherboard which had
OCP on VCore. The VCore converter would start converting
the 12V, before it was fully up. As the voltage drops on
input to a switcher, the current rises. The switcher
in a sense, is a "constant power" device. If the voltage
into the switcher drops by half, the current flow doubles.
Anyway, the VCore, upon starting its job based on some
timer, it sees maybe 6V on the 12V rail, thinks there is
an overload, and it "latches off". The customer motherboard
will not start. By switching off the power supply, the
latched status gets cleared, but the same thing will happen
on a second attempt. The solution is to mix different brands
of power supplies and motherboards, to avoid the "problem pair".

Your system, by looping like it is, is telling us that
no latching behavior coming from the motherboard is involved.
As that would stop the loop in a "failed state".

Yours keeps trying. That suggests, mainly, a problem
between the supply and the motherboard. Motherboard
is treating power supply "poorly". Bitch-slapping it.

This suggests some sort of issue with Power_Good, and
about all I can suggest is something is amiss with loading
which is ****ing off the power supply. Maybe it's the
"transient" of the VCore starting up with the full 12V
present.

There is a limit to how much capacitance can be on the
DC rails powered by your ATX supply. It's about 5000uF
per rail. The PSU has internal caps that account for
a fraction of that. The motherboard has bulk capacitors
for filtering too. The sum total on a particular rail,
should not exceed 5000uF to maintain sufficient phase
margin on the ATX control loop. While it would be
tempting to (as a hobbyist) suggest "adding more
capacitance", you have to be aware that these designs
only have 45 degrees of phase margin, up to a certain level.
And that spec (knowing how power supplies behave),
is hard to get. Even for an engineer, if I phone up
some fly-by-night operation in China, I would have a
hard time getting a definitive statement on that. The
above is simply a suggestion of a typical scenario.

If you had a pulse-catcher, you'd arm it right after
pushing the front panel power button, then see if it
catches a low-going transition on Power_Good. That would
be an indication that a "slug-of-current" was being drawn
by the motherboard. Such analysis is easy to do...
if we're back in the lab with our $35K storage scope :-)

My clamp-on ammeter can record the "peak" current in an
interval of time, and my voltmeter has both peak voltage
and lowest voltage detection. But these capabilities are
related to the sampling rate of the devices, and the
event we're looking for, is too short to catch
with these capabilities in measurement devices.
Even an HP meter with a 1KHz sampling rate and
peak detection, might miss what we're trying to see.

A storage scope wouldn't miss it.

*******

A second question for you might be, have you recently
changed the video card ? Try putting the old one back
as a test. Or even, pull the video card, and see if
the system enters the "missing video beep state"
properly. This would then indicate that the system
has survived the power up transient and the BIOS
code is getting to run. If the looping behavior continues,
with the (high power or new-ish) video card removed, then
you're no closer to an answer (it's not the video card
or the BIOS code that loads the video config space ROM).

Â*Â*Â* Paul


Wow! You've given me a lot to think about. But I just found another clue
maybe.

It seems that moving the RAM SIMM from one slot to another or adding
another SIMM makes it boot the next time I start it. It still does an
on/off try first before it actually boots. I tried just popping it out
and back in the same slot, and that did not seem to do the same.Â* This
is getting weird.


It will also boot if I remove the SIMM and replace a different brand of
SIMM in the same slot, but will not work if I replace it with a
different SIMM of the same type.
  #7  
Old April 1st 20, 10:49 PM posted to alt.comp.hardware.pc-homebuilt
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default Post problem with Z77H2-A3 motherboard

Bob F wrote:

On 4/1/2020 10:55 AM, VanguardLH wrote:
Bob F wrote:

My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?


The first and cheapest fix that I'd try is replaced the CMOS battery.
Afterward, clear the table in CMOS to force it to retrieve a fresh copy
from the EEPROM since what is in the table might be corrupt.

Its manual doesn't say what type of battery is used to keep power to the
RTC chip (with the CMOS table), but the mobo diagram shows a round
battery. That is likely a CR-2032 coin cell battery.


Thanks. I have checked the battery and reset the CMOS multiple time.


Does "checked the battery" mean you replaced it?

Next check is to disconnected all internal components from the PSU
except the motherboard and the hard drive from which the OS gets loaded.
If the mobo has video support, you may even have to remove a video card,
if present, and resort to using the onboard video. Also disconnect all
peripherals except the keyboard and mouse. That will reduce the load on
the PSU during boot. If the computer boots reliably under the reduced
hardware configuration, you'll likely need a new PSU.
  #8  
Old April 2nd 20, 12:50 AM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
external usenet poster
 
Posts: 1,467
Default Post problem with Z77H2-A3 motherboard

Bob F wrote:


Wow! You've given me a lot to think about. But I just found another
clue maybe.

It seems that moving the RAM SIMM from one slot to another or adding
another SIMM makes it boot the next time I start it. It still does an
on/off try first before it actually boots. I tried just popping it out
and back in the same slot, and that did not seem to do the same. This
is getting weird.


It will also boot if I remove the SIMM and replace a different brand of
SIMM in the same slot, but will not work if I replace it with a
different SIMM of the same type.


That's a good observation.

I can go through the background, but at the moment,
no good theory comes to mind as to a failure mode.

First of all, the "double start" thing.

When the system comes up cold, the first start,
the clockgen is at 100.0MHz ("default") and all
programmable voltages are at default too. The system
is not overclocked at this point.

Now, in the BIOS, you may have programmed an overclock
into the system. Or maybe you cranked VDimm from 1.5V
to 1.55V or something.

What the BIOS does, in this stunted first phase, is it
reads your BIOS settings, and programs the hardware.
For some exotic settings, there can be an "overclock
controller chip". Attansic made a simple one. It might
have recorded a FID and a VID calue. The BIOS loads such
a chip with the desired FID and VID. Then the BIOS executes
a RESET instruction (this allows the hardware to re-init
after the voltage regulators settle down). During the
first phase, the BIOS also records, in a non-volatile
hardware feature, the fact that "it's finished the overclock setup".

The second time the system starts (after the RESET
instruction deasserts) and the BIOS code runs, it checks
"Did I program the overclock settings yet?".
If so, it can enter the second phase, which is to do all
the normal things and pass control to an OS boot process.

For any subsequent restarts, where the system is "warm" and
the overclock controller isn't losing any settings, the
system continues to come up in the second phase mode. It no
longer needs to use that cold start code.

*******

The second issue is, why is the system behaving differently
when you change installed hardware ?

The old BIOS had DMI/ESCD. Part of this storage area in the
flash, gets updated with details about the hardware
inventory. Using Intel "DMI Explorer", you could print out
the info, including details of the RAM DIMMs being used in
the machine. Maybe a program like Lavalys Everest would
also print out the DMI table.

To record the information properly, the BIOS must have
a functional "EEPROM segment erase" routine. It erases
the DMI segment, and it then re-writes the DMI. The DMI
only needs to be written, if new hardware is inserted.

If the same DIMM stays in the machine, from one cold boot
to the next cold boot, then the DMI segment doesn't need
a re-write. The computer can in fact, remain stable for
months, without making changes to the flash.

OK, let's take another scenario. Our hero the home
builder, puts together a new machine. The motherboard is
an early one, an "initial batch" board, with BIOS #1 in it.
The web site has BIOS version #7, but the home builder says
"well, it's running, what do I care".

Little does that builder suspect, but the BIOS #1 doesn't
properly recognize the CPU. It's a newer CPU, and the BIOS
microcode and some other codes, may not recognize it. Every
time that the system comes up, the BIOS checks and it says
to itself "hmmm, this CPU does not match what is in the DMI
table, I will rewrite the DMI table". But what it writes in
the DMI table, doesn't really match the CPU. The next time
the system comes up, the BIOS does the same thing. In fact,
it's re-writing the BIOS every time that the system is
powered up. Maybe that's 365 rewrites a year, that the user
applies to the BIOS.

At some point, writing to the DMI may be failing.

OK, now at this point, I'm out of theories.

Should the machine "tip over" if the DMI doesn't work ?
It's not really a big deal, this DMI thing. It's not
critical path for the computer to work. It's
"window dressing".

And we don't know whether that's what is happening or not.

The fact that the system won't start if similar DIMMs are
swapped, but does start if there is a significant config
change (you move the DIMM from slot #2 to slot #3), that
tells us the DMI is actually working. Because from run
to run, it's able to track inventory, and it knows
whether "the new DIMM is different enough".

OK, again, why is this making a difference ?

I haven't a clue.

But, it's a good observation. It also means, if you
had a PCI Port 80 card, you could watch the progress
codes as the BIOS emits them. (Some enthusiast motherboards
have two seven segment display LED devices on the motherboard,
as a built-in Port 80 display.)

This article shows some of the many versions of Port 80
card. I thought there was a PCI Express one, but I don't
have any samples of these things here. One of the reasons
I never bothered to buy one, is every time someone
asks for help and says "my last progress code is 0xAB"
and I crack open the mobo manual, 0xAB will be missing from
the table. If the manual does not properly document
the codes, all of them, it severely restricts the value of this
debug method. And because they're progress codes,
the code might be "beginning keyboard init". We don't
know what went wrong, all we have discovered is we
might have entered a keyboard initialization subroutine
and never returned from it. This is hardly a lot to go on.
About the most value you get from this is, "well, the
lights are blinkin, that's a good sign". But they keep
dumping those codes to I/O Port 80 hex, (decimal 64),
and it is what it is.

https://en.wikipedia.org/wiki/POST_card

If you can borrow a PCI Debug Card, then it's worth testing
it out. But if you have to buy one to gain access, I
probably wouldn't bother. If local computer stores
would sell them at the same price as an Ebay seller,
I'd tell you to get one. But as long as they're
charging $100 for a $15 retail item, I can't really
recommend it. The person in China making those,
is getting a lot less than $15 for it.

Paul
  #9  
Old April 2nd 20, 01:38 AM posted to alt.comp.hardware.pc-homebuilt
Flasherly[_2_]
external usenet poster
 
Posts: 2,407
Default Post problem with Z77H2-A3 motherboard

On Wed, 1 Apr 2020 09:40:16 -0700, Bob F wrote:

My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked fine
for years, then started having occasional problems when turned on, it
would not post occasionally. The problem got more frequent over months,
until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour of
turning the power supply on, pushing the power switch, watching it spin
the fan for 2 seconds, stopping, then powering the fan for a second,
stopping, then powering the fan for a second...... When it does
actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test for
40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to the
neighboring black wire, and that did nothing also. Unplugging the power
supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this kind
of problem, or point me to any references that might educate me on the
related circuitry?


The fact that boards work fine for years without issues, until they
show up with them, used to mean to me maybe five years for
acceptability. Buying a fair amount of motherboards was the solution,
past an initial power supply swap, depending on further corrections
and balances on issues and how bad the end state actually is within a
state possibly known as operating on kludges: Imperfection as entropy
variously within a potential failure due to substandard hardware,
inconsistencies within a supportive hardware subsystem, not to
disallow software for further complicities.

Then one day I switched to a different MB brandmake and that all
changed. I started seeing longer than these "some of years" usage,
glimpsing beyond that even into a decade. The problem remains one
though that is quintessentially dynamic, that the brandmake MB I've in
mind in not something conclusive to continued and qualifiable
longevity.

It's a bet, I'd make, to say they are, as indeed they do, at so they
would say they make MBs to last longer than, say, XYZ or even ECS. But
when a MB maker begins to sell their products for $300/US, as perhaps
readily so across quantitively more model numbers, as would ASUS, the
situation changes to me.

Returning to brandmake boards for a few years usage, on a one year
warranty, whereby it's ensured to work without issues, is one thing,
at $50/US MB prices I've usually paid to build a computer, including a
spate of these longer-built quality brands I've run into. Whereas
$300/US is more like a sickness if ASUS, among top 5 brands, is
proposing in any sense a future model for return that value.

At some point, nonetheless, that's were it devolves, to where how much
are issues seen correctable among general anomalistic trends as they
continue to devolve into greater disparity and divergence from an
acceptable allowance for continuing to favor them from a "kludge
factor" of sustainable substandarization.

The two prior models of MB I have, since updating both, one was
destroyed by lightning intercepted from the modem, while the other
remains a buttress to longevity and still works (if one can conceive
of living with only two SATA ports the manufacturer provided it at
that time, also being "years ago").
  #10  
Old April 2nd 20, 02:24 AM posted to alt.comp.hardware.pc-homebuilt
Bob F
external usenet poster
 
Posts: 153
Default Post problem with Z77H2-A3 motherboard

On 4/1/2020 2:16 PM, Bob F wrote:
On 4/1/2020 1:48 PM, Bob F wrote:
On 4/1/2020 11:05 AM, Paul wrote:
Bob F wrote:
My ECS Z77H2-A3 V1.2 motherboard with an I5-2500K processor worked
fine for years, then started having occasional problems when turned
on, it would not post occasionally. The problem got more frequent
over months, until it finally is next to impossible to get it to post.

When it does post, it seems to work fine, but it might take 1/2 hour
of turning the power supply on, pushing the power switch, watching
it spin the fan for 2 seconds, stopping, then powering the fan for a
second, stopping, then powering the fan for a second......Â* When it
does actually boot, it seems to be on the second start of the cycle.

This morning, I got it to boot, and ran it with the OCCT stress test
for 40 minutes with no errors.

I then tried it with a different power supply which works fine on
another board. On the problem board, pushing the start button did
nothing. I tried jumping the green wire on the power connector to
the neighboring black wire, and that did nothing also. Unplugging
the power supply and using the jumper started it fine.

It seems to me that this is some kind of problem with the start
circuitry of the motherboard, and does not seem to affect the
processor's operation at all if it can start.

Can anyone suggest anything that might be a repair option for this
kind of problem, or point me to any references that might educate me
on the related circuitry?

1) Mostly a waste of time, but a PCI port 80 card or similar,
Â*Â*Â* could show you some "progress codes". But if the Port 80
Â*Â*Â* card only shows "FF" or "00", then the CPU isn't getting
Â*Â*Â* a chance to execute any code. If you happen to own a PCI port 80
Â*Â*Â* card, then use it. But don't waste your time and money tracking
Â*Â*Â* one down. A local computer store might charge $100, for an
Â*Â*Â* item worth $10 to $15 or so.

2) At a guess, Power_Good (from the PSU) is deasserting,
Â*Â*Â* just after the RESET pulse finishes. And this will eventually
Â*Â*Â* result in another RESET pulse being generated (looping behavior).

When the system comes up, measure the current flows on the main
ATX power cable with a clamp-on DC ammeter. What you're looking
for, is loading which is out of normal. With the "modern" power
supplies with the all-black wiring and sleeving that prevents
access to individual conductors, this is "difficult to impossible".
Thanks to "progress", we're denied a valuable debug input.

A "proxy" for overloads, is to measure the 3.3V, 5V, 12V voltages.
As those have the main DC loads. You might also check the -12V and
the +5VSB for the sake of completeness.

When using voltages as a proxy, we're looking for crossloading
effects. The short and sweet is, if one of the rails is
"abnormally low", suspect it's the one drawing too much current.

For example, the supply might have +/-5% tolerances. If one rail
is 1% below nominal, and the other rails are higher by 1%, that
hints that the below-normal one is up to something.

Each generation of computer, has a different loading pattern
for rails. The best time to establish norms, is to measure
the rails when the system is working. Or, if you have two
different manufacturers of systems in the same generation
of that hardware, compare the readings to see what typical
practice is.

My old Nforce2 board, a board which doesn't use +12V for the
processor, the +5V rail has a loading of 25 amps while gaming.
This would "tip over" almost all the supplies in the
current Newegg catalog.

Modern systems don't do that. You might expect 3.3V @ 6A or
5V @ 6A for deriving chipset voltages. These are moderate
loads compared to the PSU 3.3V @ 20A and 5V @ 20A capability.
Each hard drive, draws 1A from 5V. The optical drive can
draw a bit more than that.

The Power_Good signal from the PSU, is not the end of the
story in terms of the Power_Good concept. The purpose of
Power_Good, is to assure that the voltages are stable,
after the 35 millisecond capacitive load charge-up phase.
Hard drives, for example, won't start to spin until the
12V is a hair over 11V and rising. The hard drive, in a
sense, has its own private copy of Power_Good, which guides
its operation and loading characteristic. It doesn't
get to look at the ATX Power_Good for advice.

Some motherboard designs, use a Wired-OR of the PSU Power_Good,
plus a "good" indicator coming from various switching converters
on the motherboard.

As an example of an anomaly encountered years ago, two
brands of products would not "play nice" with one another.
An Antec supply, was "slow" raising its rail voltages. The
capacitive charging phase seemed to be slower than normal.
Then, you would combine that with a motherboard which had
OCP on VCore. The VCore converter would start converting
the 12V, before it was fully up. As the voltage drops on
input to a switcher, the current rises. The switcher
in a sense, is a "constant power" device. If the voltage
into the switcher drops by half, the current flow doubles.
Anyway, the VCore, upon starting its job based on some
timer, it sees maybe 6V on the 12V rail, thinks there is
an overload, and it "latches off". The customer motherboard
will not start. By switching off the power supply, the
latched status gets cleared, but the same thing will happen
on a second attempt. The solution is to mix different brands
of power supplies and motherboards, to avoid the "problem pair".

Your system, by looping like it is, is telling us that
no latching behavior coming from the motherboard is involved.
As that would stop the loop in a "failed state".

Yours keeps trying. That suggests, mainly, a problem
between the supply and the motherboard. Motherboard
is treating power supply "poorly". Bitch-slapping it.

This suggests some sort of issue with Power_Good, and
about all I can suggest is something is amiss with loading
which is ****ing off the power supply. Maybe it's the
"transient" of the VCore starting up with the full 12V
present.

There is a limit to how much capacitance can be on the
DC rails powered by your ATX supply. It's about 5000uF
per rail. The PSU has internal caps that account for
a fraction of that. The motherboard has bulk capacitors
for filtering too. The sum total on a particular rail,
should not exceed 5000uF to maintain sufficient phase
margin on the ATX control loop. While it would be
tempting to (as a hobbyist) suggest "adding more
capacitance", you have to be aware that these designs
only have 45 degrees of phase margin, up to a certain level.
And that spec (knowing how power supplies behave),
is hard to get. Even for an engineer, if I phone up
some fly-by-night operation in China, I would have a
hard time getting a definitive statement on that. The
above is simply a suggestion of a typical scenario.

If you had a pulse-catcher, you'd arm it right after
pushing the front panel power button, then see if it
catches a low-going transition on Power_Good. That would
be an indication that a "slug-of-current" was being drawn
by the motherboard. Such analysis is easy to do...
if we're back in the lab with our $35K storage scope :-)

My clamp-on ammeter can record the "peak" current in an
interval of time, and my voltmeter has both peak voltage
and lowest voltage detection. But these capabilities are
related to the sampling rate of the devices, and the
event we're looking for, is too short to catch
with these capabilities in measurement devices.
Even an HP meter with a 1KHz sampling rate and
peak detection, might miss what we're trying to see.

A storage scope wouldn't miss it.

*******

A second question for you might be, have you recently
changed the video card ? Try putting the old one back
as a test. Or even, pull the video card, and see if
the system enters the "missing video beep state"
properly. This would then indicate that the system
has survived the power up transient and the BIOS
code is getting to run. If the looping behavior continues,
with the (high power or new-ish) video card removed, then
you're no closer to an answer (it's not the video card
or the BIOS code that loads the video config space ROM).

Â*Â*Â* Paul


Wow! You've given me a lot to think about. But I just found another
clue maybe.

It seems that moving the RAM SIMM from one slot to another or adding
another SIMM makes it boot the next time I start it. It still does an
on/off try first before it actually boots. I tried just popping it out
and back in the same slot, and that did not seem to do the same.Â* This
is getting weird.


It will also boot if I remove the SIMM and replace a different brand of
SIMM in the same slot, but will not work if I replace it with a
different SIMM of the same type.


The BIOS seems to default to running at the 1600MHz the RAM is rated
for. If I change memory clk multiplier to manual at 10 instead of 12, it
will now boot every time at 1333 MHz. It does still do the double start,
like it would do if overclocked too much when I was last using it full time.

I did not previously have to do any of this slowing things down. I am
beginning to think this board is just fading significantly.

I just read your latest comment, and it gives me a lot more to think
about. The DMI rewrite thing could be involved. Could it be that the DMI
is failing and replacing the BIOS chip might clean up my problems?

Another step backwards. Now, I just discovered that the Motherboard is
not shutting off the power supply when it shuts down. This is really
getting frustrating. Resetting the BIOS to default does nothing for this
one.
 




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