I think it must be the power supply [Asus]

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From: hemm99 on 19 Jan 2010 18:18

On Tue, 19 Jan 2010 08:57:50 -0500, Bill Anderson
<billanderson601(a)yahoo.com> wrote:

>Bob wrote:
>> On Mon, 18 Jan 2010 13:15:18 -0500, Bill Anderson
>> <billanderson601(a)yahoo.com> wrote:
>>
>>>
>>> Well look here -- I've come back to update a thread that's almost a year
>>> old. Never thought it would take this long to revisit the subject, but
>>> here I am again.
>>>
>>> To recap: Last February my computer would refuse to post when I turned
>>> it on in the mornings. The fans would fire up and the optical disk
>>> drive light would come on, but no post, no boot. So I'd hold the power
>>> button in for about five seconds and the power would shut off and I'd
>>> push the button again and this time the computer would post and boot --
>>> or not. Repeat, repeat, repeat, ah ... there's the beep and we're in
>>> business.
>>>
>>> My best guess, and the best guess around here, was that the power supply
>>> was the problem. When I removed my PC Power and Cooling power supply
>>> and replaced it with a no-name spare, the problem went away. Ah-hah!
>>>
>
>OK, I really need some help now. This morning, with the no-name spare
>PS installed, I powered up the computer but it didn't post. I powered
>down as described above, waited a few seconds, and pushed the power
>button again. This time the computer powered up and after a few seconds
>it powered down. Then it powered up again and then it powered down.
>Then it powered up and then it powered down again, this time for good.
>I didn't touch the computer at all during this -- I just watched in
>amazement.
>
>Then I pushed the power button and powered up and no post. So I powered
>down and powered up again and this time I got a beep and now all is well.
>
>The problem isn't the power supply. But what could it be? I don't know
>what to look at first. Help?

I just had the same problem and in my case it was a memory stick. I
was able to duplicate the problem by gently pressing on the bad stick.
Press one way and it would not boot. Press the other way and it would
boot every time. Cleaning the memory sticks contacts and all is well.

From: Paul on 19 Jan 2010 20:49

Bill Anderson wrote:
> Bob wrote:
>> On Mon, 18 Jan 2010 13:15:18 -0500, Bill Anderson
>> <billanderson601(a)yahoo.com> wrote:
>>
>>>
>>> Well look here -- I've come back to update a thread that's almost a
>>> year old. Never thought it would take this long to revisit the
>>> subject, but here I am again.
>>>
>>> To recap: Last February my computer would refuse to post when I
>>> turned it on in the mornings. The fans would fire up and the optical
>>> disk drive light would come on, but no post, no boot. So I'd hold
>>> the power button in for about five seconds and the power would shut
>>> off and I'd push the button again and this time the computer would
>>> post and boot -- or not. Repeat, repeat, repeat, ah ... there's the
>>> beep and we're in business.
>>>
>>> My best guess, and the best guess around here, was that the power
>>> supply was the problem. When I removed my PC Power and Cooling power
>>> supply and replaced it with a no-name spare, the problem went away.
>>> Ah-hah!
>>>
>
> OK, I really need some help now. This morning, with the no-name spare
> PS installed, I powered up the computer but it didn't post. I powered
> down as described above, waited a few seconds, and pushed the power
> button again. This time the computer powered up and after a few seconds
> it powered down. Then it powered up again and then it powered down.
> Then it powered up and then it powered down again, this time for good. I
> didn't touch the computer at all during this -- I just watched in
> amazement.
>
> Then I pushed the power button and powered up and no post. So I powered
> down and powered up again and this time I got a beep and now all is well.
>
> The problem isn't the power supply. But what could it be? I don't know
> what to look at first. Help?
>

The oscillating behavior means there is a problem somewhere around +5VSB
and PS_ON#.

PS_ON# is an open collector signal driven by the motherboard end. When
pulled to ground, it indicates "I want the main rails of the supply on
now". When the signal is left floating, a pullup resistor on the power
supply end, pulls the signal towards +5VSB voltage rail. And that is
a "logic 1" and means "I don't want the main rails on now".

If the supply is oscillating on and off, sometimes that could be
caused by a PS_ON# signal which is floating between the two values
(zero volts and five volts). There are a number of ways to interpret that.

It could be, that a supply has a defect on the thing sampling the PS_ON#
signal.

Or, it could mean the motherboard is having trouble driving the PS_ON# signal.

Or, a third interpretation is, the +5VSB power supply rail is not at
the proper voltage. A very low voltage there, may cause the driver IC
on the motherboard to be unable to function properly.

So the problem then, is distinguishing which end is at fault. If the
condition was permanent (power supply oscillated all morning long), you
could take a multimeter and probe +5VSB and PS_ON# and see what is up.
When the events have a very short duration, it takes equipment like a
digital storage scope, to take a snapshot of the voltages.

With an Asus motherboard, you can quickly judge the +5VSB situation, by
viewing the green LED on the motherboard. The green LED is connected to
+5VSB. The +5VSB should be operating, before you push the power button on
the front. The green LED should stay at the same intensity the whole time.
For example, if you were probing PS_ON# with the multimeter, and saw the
intensity of the green LED fluctuating at the same tine as the PS_ON# voltage
was all over the place, then you'd suspect the power supply. The green LED
allows you to monitor +5VSB, while using your meter on some other signal.

Occasionally, the open collector driver on the motherboard will die, but
I don't understand quite why this happens any more frequently than any other
kind of fault on a motherboard. The circuit should not really be under
any stress. It only has a simple pullup resistor to drive to ground.

You can probe the signals on the main power supply cable with a multimeter.
Clip the black lead, to a shiny metal screw in the I/O area on the back
of the computer case. If your multimeter came with an alligator clip which
fits on the probes, that allows you to probe one-handed and that is
infinitely preferable to messing with two probes. Effectively, you're leaving
the black lead permanently clipped to ground, while you use the red probe
to check voltages.

You can poke the tip of the multimeter, where the wires enter the nylon shroud
of the main power supply connector. There is enough exposed metal on each crimp
pin, for you to be able to make contact. You could check PS_ON# there, and see if the
level before pushing the power button, is a solid 5V level (same voltage as
+5VSB). And next, when you push the power button, the meter should read one
junction voltage above ground. The driver IC should be able to pull the signal
down to 0.4V or lower. Anything below about 0.8V is a reasonable sign, while
a level of 1.5V is going to cause oscillations on the power supply end.

With regard to the original problem, it could be that this is one of those
situations, where the timing of the power supply and the motherboard are
not agreeable. Some overcurrent circuits, have time constants associated with
them. For example, your power supply will ignore overcurrent indications for
the first 35 to 50 milliseconds when the power supply is turned on. It has to
do this, because you can't really judge yet whether you're looking at the
initial charging transient (inrush current) or a real overload. So the power
supply gets through that phase of operation, by ignoring overloads.

The Vcore will do something similar. The Vcore regulator chip on the motherboard,
has some circuits intended for overload protection. They have to be disabled for
a short interval, before reliable detection is possible.

If a power supply is really slow to complete ramping a rail like +12V, it
is possible the Asus motherboard shuts down Vcore, due to a fault being
indicated. When in fact, it might just be a slow power supply aggravating
the problem. After several tries (like, with a small amount of residual
charge on the power supply), the motherboard may decide to start.

That happened a lot, with a certain Antec supply. And Antec doesn't make their
own supplies. They're made under contract. When Antec had problems with Asus
motherboards, they were opening the power supply casing when they got them in
North America, and making some mod to the supply. So this kind of disagreement
has happened before.

You might not be seeing the same kind of thing. You need to have lots of
schematics around, and test equipment, to trace down a problem like that.
It is not as trivial as just probing the main power supply cable. For
example, you might benefit from a digital storage scope, to follow the
startup transient, while monitoring the fault signal on the Vcore chip
on the motherboard. It is too bad there isn't a red LED connected
to Vcore, for monitoring for a fault.

At the current time, you've tried swapping the supply and that didn't help.
Next, would be the motherboard. Preferably, for a different model.

Paul

From: Bill Anderson on 19 Jan 2010 23:30

Paul wrote:

>
> At the current time, you've tried swapping the supply and that didn't help.
> Next, would be the motherboard. Preferably, for a different model.
>

Yeah, I was afraid of that. Paul, I really appreciate all the effort
you put into your reply, but I'm just a weekend hobbyist, not an
electrical engineer. I don't have the equipment you recommended and I
doubt I'll ever be able to follow your instructions. Thanks so much,
but the only thing you said that I can follow is that I probably need a
new motherboard.

My board is a P5K Deluxe WiFi AP. You know, I've had this thing for
something like three years which is about a year beyond my normal desire
to build a new, faster, better computer. I've gone this long because my
computer is doing everything I want to do, and doing it very nicely.
Editing video is a snap compared to past builds.

And would you believe I'm going to have major surgery tomorrow morning
and will be sitting around the house recovering for the next couple of
weeks? I've decided to leave the computer running for the next couple
of days while I'm away just so I don't come home to find a computer that
won't start.

But if all goes well, I could spend my time off building a new computer.

Here's what I have now:

Motherboard: ASUS P5K DELUXE/WIFI-AP LGA 775 Intel P35 ATX
Processor: Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache
LGA 775
Memory: Crucial 4GB Ballistix 240-pin DIMM, DDR2
PC2-8500
Video Card: SAPPHIRE 100210L Radeon HD 2600XT 256MB 128-bit GDDR4 PCI
Express x16
Power Supply: PC Power and Cooling ULTRA-QUIET PSU: SILENCER(R) 610
EPS12V
Video capture: ATI VisionTek TV Wonder PCI Express
Storage: Four 500 gigabyte hard drives -- three Western Digital and
one Maxtor.

Do you know of a better motherboard that will accept the processor and
all the rest? In other words, can I just swap out motherboards or will
I need a new processor and video card? Is it time to do a big upgrade,
or can I get by with just a new MBO that will perform as well as the
P5K? Any MBO recommendations? You've been giving me great MBO advice
since at least Sept. 2004 (I just checked Google Groups), and here I am
asking the same question I've asked several times before: What's a good
MBO for me?

--
Bill Anderson

I am the Mighty Favog

From: Ray on 20 Jan 2010 00:00

"Bill Anderson" <billanderson601(a)yahoo.com> wrote in message
news:Csydndka_rqnOMnWnZ2dnUVZ_rednZ2d(a)giganews.com...
> Paul wrote:
>> Bill Anderson wrote:
>>> Paul wrote:
>>>> Bill Anderson wrote:
>>>>
>>>>>
>>>>> Question: Could a failing power supply have been causing the video
>>>>> card flakiness? And if so, does it make any sense to replace the
>>>>> current power supply with the PC Power and Cooling unit when it
>>>>> arrives on Monday?
>>>>>
>>>>
>>>> The best way to tell, would be to connect an oscilloscope to the 12V
>>>> rail,
>>>> and watch what happens to the voltage, when the video card does a VPU
>>>> recover. A multimeter may not be able to catch a quick dip
>>>> in the voltages.
>>>>
>>>
>>> <snip>
>>>
>>> Paul:
>>>
>>> Here's what's happened so far:
>>>
>>> I sent the unit to OCZ and 2 or three weeks later (two days ago) it came
>>> back. When I opened the box I suspected I was looking at my original
>>> unit, as the rubber band I'd used to bind the wiring was still attached.
>>> No information was included to indicate what had been found or what had
>>> been done. So I sent a message to OCZ asking what had been done to the
>>> unit. The response was that the unit had been "repaired," but the
>>> technician who did the work had gone home for the day. Would I like the
>>> guy I was emailing to to ask the technician what had been done? I
>>> replied, "yes, please."
>>>
>>> Now today I've received this:
>>>
>>> Comment: Hello Bill,
>>>
>>> Does your power supply work now?
>>>
>>> Our technician could not find any problems with your power supply. It
>>> was thoroughly tested.
>>>
>>> Allen Chung
>>>
>>>
>>> So ... I responded as follows:
>>>
>>>
>>> Hi Allen:
>>>
>>> A few comments:
>>>
>>> 1) It's annoying that I must correspond with you via your "Add comment
>>> to trouble ticket" website. Because I can't see our past messages to
>>> each other -- because I have no record of what I've told you before --
>>> I feel I must recap everything in every message. Can't you include an
>>> email trail in your responses? As it is, there's no record in my note
>>> this evening to indicate what I told you in the first place about my
>>> problem, nothing to explain why you thought an RMA might be required in
>>> the first place.
>>>
>>> 2) I pretty much suspected that even though in an earlier message you
>>> told me my power supply had been "repaired," nothing had been done to
>>> it. I'm not surprised. The problem was intermittent and I worried that
>>> you would get the PS and test it and find nothing wrong.
>>>
>>> 3) Thank you at least for following up and answering my questions about
>>> what has been done with the unit I sent you. But I must point out that
>>> if I'd received a note with the unit when it was returned, something
>>> along the lines of "Mr. Anderson, we couldn't find anything wrong with
>>> this unit, we think it's not the cause of your problem, and we recommend
>>> you re-install it," you and I could have been spared some unnecessary
>>> correspondence. At least I wouldn't have needed to treat this episode
>>> as a mystery needing to be solved.
>>>
>>> 4) I will re-install the power supply this evening. Who knows? Maybe
>>> it'll work with no problems for the life of my computer. Maybe the
>>> problem was caused by a loose connection. Maybe. But I'm telling you,
>>> when I removed the 610 watt PC Power and Cooling power supply and
>>> replaced it with a no-name 400 watt power supply, the problem went away.
>>> I have not experienced any of the symptoms I described to you in my
>>> first message since removing the PC Power and Cooling unit. But ...
>>> let's give it another go and keep our fingers crossed!
>>>
>>> Thanks for your attention to my difficulties.
>>>
>>
>> I guess we'll know, when you do the test *again* and it fails :-(
>>
>> Paul
>
>
> Well look here -- I've come back to update a thread that's almost a year
> old. Never thought it would take this long to revisit the subject, but
> here I am again.
>
> To recap: Last February my computer would refuse to post when I turned it
> on in the mornings. The fans would fire up and the optical disk drive
> light would come on, but no post, no boot. So I'd hold the power button
> in for about five seconds and the power would shut off and I'd push the
> button again and this time the computer would post and boot --
> or not. Repeat, repeat, repeat, ah ... there's the beep and we're in
> business.
>
> My best guess, and the best guess around here, was that the power supply
> was the problem. When I removed my PC Power and Cooling power supply and
> replaced it with a no-name spare, the problem went away. Ah-hah!
>
> So I told my story to a nice technician at PC Power and Cooling and he had
> me ship the unit back to him and in a few days it came back to me
> unchanged. They "could not find any problems."
>
> So I put it back in the computer as described above and to my complete
> surprise the computer has been posting and booting flawlessly ever since.
> At least it has until about a week ago.
>
> Now I'm back to where I was before -- power on, no post, power off, power
> on, no post, power off, power on, BEEP!, and everything works great.
> Maybe it takes one retry, maybe five. But eventually the computer will
> post. At least that's how it's been so far.
>
> I've put the no-name power supply back in the computer and it's running
> fine. I'm going to give it a few days to see if the problem returns with
> the no-name PS. If it does, I'll know the problem is with the motherboard
> or memory or something. If I go several weeks with no problem, I'll
> probably put the PC Power and Cooling PS back in to see if the problem
> returns. If it does, then I'll call PC Power and Cooling (or whoever owns
> them now -- OCZ) and fuss. If it works with no problem, well, maybe I'll
> get another year's worth of use out of it.
>
> Can anybody think of something other than the PS that would cause this
> sort of behavior?
>
> --
> Bill Anderson
>
> I am the Mighty Favog

Bill,
I have the same exact ASUS P5k3 deluxe board and had a boot problem when I
first built the PC, it would start to power up and fail and nothing, and it
was a faulty power supply. Now the problem has returned in the same exact
form as your description, 2 years later. Flashing lights, no beep, black
screen. Only way to get it to boot is turn the reset switch on the back of
the case off and on again and reboot the main power switch on the front of
the tower. It only happens once every couple of weeks. But is annoying none
the less. I also have been getting major BSOD'S lately, I am thinking maybe
something is a miss with a driver, I did manage a screen cap of the first
BSOD and it looks like and NVIDIA error it says specifically, (N4_disp.dll)
stop error. I am thinking maybe my video card drivers are creating all my
headaches.

My configuration is
ASUS P5k3 deluxe WiFi AP.
4gb Corsair DDR3
Nvidia 9800 GTX
Windows XP Sp3

From: Ray on 19 Jan 2010 23:59

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