dave xnet wrote:


Bob

On Mon, 21 May 2007 12:36:53 -0500, Bob M <ram1220 (AT) vzavenue (DOT) net>
wrote:

the pc is shutdown restarted. You don't do this wth
yours do you ? That's madness.

Dave

On Mon, 21 May 2007 03:20:49 GMT, dave xnet
<davexnet02DEL (AT) ETEyahoo (DOT) com> put finger to keyboard and composed:

I have startup issues with an Athlon XP 2500+ in an ECS L7S7A2
motherboard. My original PSU was a 200W fake claiming to be a 400W.
Replacing it with a 350W Antec left me with exactly the same problem.
:-(

I suspect that something in my motherboard's standby circuitry doesn't
get initialised properly. There are two rails, +5VSB and +3.3VSB. The
latter is generated on the motherboard. Maybe the +3.3VSB doesn't come
up fast enough ??? Note that my problem only occurs after the AC power
is cycled. Once the machine has powered up successfully, you can shut
it down from the front switch and restart it as many times as you like
.... until you cycle the AC power again. Even then, the problem doesn't
always happen. When it does happen, I can nearly always get it to
start by powering off and on from the front switch. The reset switch
has no effect.

I suspect that there may be nothing wrong with your PSU. Instead it
could be the motherboard's standby circuitry that is at fault.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Tue, 22 May 2007 07:51:06 +1000, Franc Zabkar
<fzabkar (AT) iinternode (DOT) on.net> wrote:

<snip>
My case is slightly different; it occurred after I upgraded the cpu.
Some have said well perhaps the load increased, but both cpu's
consume 89W according to AMD.

Also, mine occurs when ever the PC is shutdown.
If I recycle my AC, it works first time.

I sent a message to Antec to see if they have any clues.

Also left a message with the CPU vendor, but haven't heard
from them yet
I have purchased a digital multimeter and I'm going to measure
the voltages as mentioned in an earlier post.
Dave

On Mon, 21 May 2007 15:51:45 GMT, dave xnet
<davexnet02DEL (AT) ETEyahoo (DOT) com> wrote:



Picked up the meter in Kmart.

Here's the results, machine off, after using shutdown in windows:
purple 5, green 5 grey 0

I waited 5 minutes and without touching any buttons, tested again,
purple 5, green 5, grey 0

Pressed the front power switch, green power LED lights but
machine does not power on. Got these voltages as fast as I could
(within about 30 seconds anyway)
purple 5, green 4.9 grey 0

I'm not sure if I full understood your instructions regarding the
"when" to test- if I should do more, please let me know.
Likewise, if you see a glaring problem already.
Thanks very much -
Dave H.

On Tue, 22 May 2007 00:50:45 GMT, dave xnet
<davexnet02DEL (AT) ETEyahoo (DOT) com> wrote:

Pressed the front button, got 4.1V on the grey wire,
PC turned on.

Power supply bad?

dave xnet wrote:
To help with the wire colors, you can get ATX power supply specs
from formfactors.org . The first two are for 20 pin supplies, and
will give you a historical perspective (i.e. what happened to pin 18).
The third one is for a 24 pin supply and is the most recent. You can
pick the spec that best matches what kind of supply you have.

http://web.archive.org/web/200304240...12V_PS_1_1.pdf
http://www.formfactors.org/developer...X12V_1_3dg.pdf

http://www.formfactors.org/developer...public_br2.pdf

The green wire is PS_ON# and when you push the front button, it should
drop from 5V to close to zero. Perhaps a value of 0.4V or so. That might
be a saturated transistor driving the line. So it appears the motherboard
is not sending PS_ON#.

So the question would be, what is gating (preventing) PS_ON# from going low ?
It is interesting that you say you "cycle the A.C." and the thing is then
startable. It implies that removing +5VSB and then making +5VSB available
again, is enough to clear the problem and allow PS_ON# to pass. A person
could blame the motherboard for this, except in situations where some
external influence upset the operation of the motherboard. I cannot
see the relationship between the new processor and old, which would
do this. (Unless the motherboard was mechanically damaged, or the
motherboard shifted and a mounting screw or standoff is shorting
something.)

The fact that your power LED comes on, on the front panel (?), says
the front panel LED is powered by +5VSB, and it also says that the
motherboard logic thinks it is driving PS_ON# active as well. In
other words, the decision to turn on the LED on the front of the
computer case, implies the motherboard also wanted the PS_ON# signal
to be active too.

In the spec, PS_ON# requires the motherboard driver to sink 1.6 milliamps.
Which is not really a lot of current, as drivers go. Pad drivers on logic
ICs, typically might have 8, 12, or 16mA drive, for general purpose I/O.
If there wasn't an open collector logic device available, Biostar could also
use a transistor, which could drive way more than that.

I downloaded the manual, and the section on "CPU overheat", describes
a function where the computer will not turn on - until the A.C. is
cycled. Maybe this is a "feature" ? (PDF page 20 - CRU51M9_0829C.pdf)
Again, it is a mystery as to why a change in processor, could lead
to this feature running amok.

http://www.biostar.com.tw/products/m...orce%206100-M9
http://www.biostar.com.tw/products/m...%206100-m9.exe

Just out of curiosity, what does the hardware monitor read for a CPU
temperature, when the motherboard does manage to run ? Is the temp
normal or is it out of whack (like 255C) ?

Paul

dave xnet wrote:
The grey wire is PWR_OK. Since the power supply turned on, PWR_OK is
going high as a means of the power supply saying that all rails
are ready. That is pretty normal. We know your other situation is
abnormal, because no fans spin. Which means it isn't likely the grey
wire will rise from zero volts in that case - no fans, no +12V, no
reason for PWR_OK to be asserted.

Paul

On May 21, 8:50 pm, dave xnet <davexnet02... (AT) ETEyahoo (DOT) com> wrote:
A meter should be reporting at least three digits. Reason why an
analog meter is insufficient: we need more than one digit. If only
one digit displayed, then the meter switch should be switched to 20
volt DC range. 0 could be OK or too high. Is zero 0.2, 0.6, or 0.75?

Assuming those numbers are 5.00, 4.90, 0.00, etc: When power switch
is pressed, then power supply controller should drop green wire
voltage to near zero (well below 0.80 volts). Power supply controller
is not telling power supply to power on if voltage remains well above
2 volts.

Power supply controller has to inputs: power switch and purple
wire. Purple wire remaining at 5.00 volts is OK. Now connect meter
to two points where power switch connects to motherboard. Voltage
between those two points should measure something less than 5.00
volts. When switch is pressed, then that voltage should drop to zero
(well less than 0.80 volts). If yes, then other power supply
controller is getting good inputs. We move on.

If both power supply controller inputs are OK, then power supply
controller is somehow defective OR something inside power supply is
creating so much current as to hinder (overwhelm) the controller's
'Power On' request. Final test is to use meter in current mode. This
typically means moving a lead from the Volt-Ohm hole to the Ampere
hole; and setting meter in a maximum current range (2 amps?).

Remove AC power cord. Then disconnect that 20 something pin
connector and other power connector (near CPU) from motherboard.
Attach meter leads to green and any black wire. Restore AC power to
power supply. Power supply will probably power on fans, disk drive,
etc

Now slowly reduce meter range switch so that zero increases to a
useful multidigit number. If that current is less than 0.01 amperes
(10 milliamps), then power supply is not overwhelming power supply
controller output - a good condition. Therefore problem is isolated
to the power supply controller located on motherboard.

Sidenote. Note when purple wire is and is not at 5 volts. Only
time you can add or remove hardware is when purple wire is zero
volts. That means removing power cord from power supply or AC wall
receptacle every time before making any changes. When power cord is
restored, then safety circuits on power supply controller are reset.
IOW if green wire responds to power switch right after power cord is
reconnected, then one possible suspect is the 'reset' safety lockout
circuit inside power supply controller. Removing and reconnecting
power cord resets that safety lockout circuit.

Learn what does and does not permit power switch to cause green wire
voltage to drop below 0.8 volts. Is it an intermittent switch? Does
purple wire voltage sometimes dip slightly below 5.00 volts? Or does
green wire drop for only one second after power switch if pressed?
Symptoms, when posted here, may also result in more useful
information.

On Mon, 21 May 2007 21:58:49 -0400, Paul <nospam (AT) needed (DOT) com> wrote:

One thing did happen during the course of the cpu transplant.
There are 4 or 5 capacitors in a row next to the heatsink/fan
The side of my hand accidentally applied a little pressure to the one
on the end of the row when I was negotiating with the HSF retaining
clips.
It seems so minor that I had all but dismissed it.
Perhaps I dislodged or loosened one of it''s connectrs
I can check it, but I'll have to remove the motherboard and look at
the back - perhaps resolder it.
But is it safe to reset the CMOS while the power line is attached?
If not, surely one implies the other.
if it is I'll try this/
page.
Also a program called Aida32, which I think is an earlier version of
Everest. The idle temps are about 34C, while about 46 under load.
I've touched the side of the HSF it's generally cool to the touch.
It is certianly making contact with the processor.
I don't see the cpu overheating, perhaps the sensor is bad?
aida32 doesn't report this. What else can I check it with?

I don't have the necessary expertise, knowledge or experience to do
much more of this diagnosis that you and w_tom have suggested.

At this point, I'm getting ready to put back the old cpu and see if it
still occurs. If it does, at least then I'll know that either the
mobo or power supply is bad( I think)
However, what if I put in the old cpu and it's working
perfectly?