Constant Reboot Cycle at Startup


M

Matt

Hey guys. I have just finished putting my new build together, the
specs for which are at the bottom of this post. However, upon
switching it on I have come across a problem. After a few seconds of
booting up, the computer just turns itself off, then restarts again a
few seconds later. It gets about 10 seconds in before the reboot kicks
in, which isn't enough time for my LCD monitor to kick in and give me
any information it seems :(

Any idea what could have caused this? I'm a little tired by now so I'm
hoping it's just a silly little mistake I can easily fix.

I have tried connecting my PS/2 keyboard in case it wasn't picking up
the wireless keyboard, but it had no effect. In case it was the PSU
struggling tto cope (though I'm certain it has plenty of capcity to
cope with this setup) I disconnected both hard drives, but still
didn't get anywhere. Finally, I have tried booting up with my WIndows
XP CD in the drive so it has something to boot from, but again that
didn't help.

Kind Regards,

Matt

P.S. If this is of any help, I have kept the side of the case off so I
can see what's going on inside the case. One thing I have noticed is
that the CPU fan tends to start rather sporadically (i.e. occasionally
it will start up a second or two after everything else. Other times it
starts with the other fans). I have the CPU fan in the CPU-FAN
connector on the motherboard (and since it only fits it one way I
don't have it the wrong way round).

My new build:

Intel Core 2 Quad Q9450 2.66GHz 12M Cache S775 1333MHZ
Gigabyte S775 Intel X48 DDR2 ATX Audio Lan 1600FSB 6xSATAII
Corsair 4GB (2x2GB) DDR2 800MHz/PC2-6400 CL5(5-5-5-18) Heat Spreader
2 x Western Digital Caviar 500GB S300 16mb 7200rpm
Gigabyte Radeon 4850 512MB PCIE 2xDVI
Akasa VORTEXX Neo Cool Blue Graphics Card Cooler
Antec 300 Three Hundred Case - No PSU
Corsair Memory 550W VX PSU
Logitech LX710 Wireless Keyboard
Microsoft Wireless Optical Mouse 5000 (Metallic Grey)
Samsung BLACK 20x IDE DVD Writer With Nero Retail
 
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J

John Doe

Matt said:
Hey guys. I have just finished putting my new build together,
Congratulations.

Any idea what could have caused this? I'm a little tired by now so
I'm hoping it's just a silly little mistake I can easily fix.

When I'm a little tired, I make more mistakes. One reason is exactly
because I'm looking for something that can be easily fixed instead
of hunkering down and solving the problem the right way. Best thing
to do is get some rest and start fresh. Patience is a virtue when
building a system.

Good luck and have fun.
 
P

Paul

Matt said:
Hey guys. I have just finished putting my new build together, the
specs for which are at the bottom of this post. However, upon
switching it on I have come across a problem. After a few seconds of
booting up, the computer just turns itself off, then restarts again a
few seconds later. It gets about 10 seconds in before the reboot kicks
in, which isn't enough time for my LCD monitor to kick in and give me
any information it seems :(

Any idea what could have caused this? I'm a little tired by now so I'm
hoping it's just a silly little mistake I can easily fix.

I have tried connecting my PS/2 keyboard in case it wasn't picking up
the wireless keyboard, but it had no effect. In case it was the PSU
struggling tto cope (though I'm certain it has plenty of capcity to
cope with this setup) I disconnected both hard drives, but still
didn't get anywhere. Finally, I have tried booting up with my WIndows
XP CD in the drive so it has something to boot from, but again that
didn't help.

Kind Regards,

Matt

P.S. If this is of any help, I have kept the side of the case off so I
can see what's going on inside the case. One thing I have noticed is
that the CPU fan tends to start rather sporadically (i.e. occasionally
it will start up a second or two after everything else. Other times it
starts with the other fans). I have the CPU fan in the CPU-FAN
connector on the motherboard (and since it only fits it one way I
don't have it the wrong way round).

My new build:

Intel Core 2 Quad Q9450 2.66GHz 12M Cache S775 1333MHZ
Gigabyte S775 Intel X48 DDR2 ATX Audio Lan 1600FSB 6xSATAII
Corsair 4GB (2x2GB) DDR2 800MHz/PC2-6400 CL5(5-5-5-18) Heat Spreader
2 x Western Digital Caviar 500GB S300 16mb 7200rpm
Gigabyte Radeon 4850 512MB PCIE 2xDVI
Akasa VORTEXX Neo Cool Blue Graphics Card Cooler
Antec 300 Three Hundred Case - No PSU
Corsair Memory 550W VX PSU
Logitech LX710 Wireless Keyboard
Microsoft Wireless Optical Mouse 5000 (Metallic Grey)
Samsung BLACK 20x IDE DVD Writer With Nero Retail

The first thing I'd check, is the CPUSupport chart, and see
what version of BIOS might be required to run the processor.
A recent board like that, may support a Q9450 out of the box,
but I'd recheck that just to be safe. Some brands of motherboards
put the BIOS release number on a sticker on the BIOS chip, so
you have some way to figure out what you got.

The Gigabyte web site right now, isn't working right. I suspect
there is more than one model with an X48 chipset, so I cannot
download the manual for a look, or even list the models.

One possible reason for the CPU fan to hesitate at startup, could
be the control method used for the fan. Gigabyte likes to use the
fan control interface available on some Intel chipsets, and it is
run by a microcontroller in the chipset. Depending on the mood that
is in, there could be any number of weird behaviors caused by the PWM
pin connected to the CPU fan. So I wouldn't draw any conclusion
from the behaviors (unless the fan simply refuses to start or something).

The processor is protected against overheating, by THERMTRIP, and that
will turn off the computer if the internal threshold temperature is
exceeded. The computer will switch off without warning if
THERMTRIP happens (no software is needed to turn off the computer).

For testing, I like to assemble methodically, starting with the
simplest hardware configuration and working up. For example,
with motherboard and power supply, and nothing else, the front
power switch should be able to turn the power supply on and off.
I'd let it run for a minute or two, just to see if the power
supply is happy. (I have a home made load box for ATX PSUs, and
I use that to test power supplies, just so I have a reasonable
assurance they won't burn the new board. So for me, the motherboard
plus power supply test, is more about testing the motherboard logic
that turns on the PSU.)

The second test, is to install the CPU, and its heatsink/fan. Connect the
computer case speaker, so you can monitor for beep codes. Since the
motherboard has no RAM present, you would expect to hear a beep code
for missing RAM. If you hear the repetitive beep, that is proof
that the CPU has executed some BIOS code, and managed to program
some of the hardware to deliver the beep. If the computer won't
beep (or if you have a port 80 debug card, and the display won't change
from FF hex), then you'd know there was a basic problem with the CPU
executing code. (You might suspect a BIOS chip with bad code in it, or
a lack of +12V being delivered to the ATX12V 2x2 power connector,
and so on. Check that the 2x2 square power connector is plugged in.)

The next test would be to add some RAM. The result, should be a beep
code complaining that there is no video card. After the video card
is added, then the computer may put visual error messages on the
output of the video card (so no more beep codes). It could complain
about no keyboard/mouse, or no boot drive, and so on.

So you can get a lot of information, from the two possible outcomes
of each of a series of test cases.

A reboot after 10 seconds, doesn't ring any bells. At least some
faults, should cause the computer to stop, and not start again,
until you toggle the power on the back of the computer. So that
eliminates a few things. It could be a power supply "tipping over",
but again, having the power supply carry on as if nothing happened
doesn't make sense. Another thing to observe, is the time constant
of every reboot. If the reboots were thermally related, then you'd
expect the interval to change, if starting the system from a
"cold" state. If the reboot interval is exactly the same each time,
I might suspect the BIOS is not happy about something. Thus
my advice in the first paragraph.

HTH,
Paul
 
M

Matt

Thanks for such a thorough reply.

I have just tried stripping everything out and disconnecting
everything, leaving just the PSU connected to the motherboard and
causing a slight difference has emerged. Now the computer runs for
only 3-4 seconds, then turns itself off, but it doesn't restart again.
I then tried resetting the BIOS, but there was no change.

I then tried adding just the CPU, and the reboot cycle came back with
a period of 10 seconds again.

I'm now going to try using the 570W Trust PSU I have in my current
computer. I wouldn't trust it to be able to handle everything in my
new build, but powering the motherboard and CPU alone should be within
its capabilities.

Will post back when it's done.

Kind Regards,

Matt
 
M

Matt

Ok, slightly strange reaction to the new PSU.

Initially there was no change with only the Trust PSU inserted into
the motherboad and all other components not connected. However, when I
tried clearing the BIOS again with the new PSU, the computer then
booted fine. I ran it for a full two minutes without any problems.

I then tried adding components one-by-one with the Trust PSU inserted.
Sadly I only got as far as the CPU before the reboot problem came
back. I have noticed that the CPU fan, even when it is running, is
spinning very slowly. I have a molex adapter somewhere, so I'll try
and bypass any fan speed control on the motherboard.

Kind Regards,

Matt
 
M

Matt

Annoyingly it's a 3 pin adapter, so no joy with that. I'll try getting
a desk fan blowing on the CPU so see if that makes any difference.

Kind Regards,

Matt
 
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P

Paul

Matt said:
Ok, slightly strange reaction to the new PSU.

Initially there was no change with only the Trust PSU inserted into
the motherboad and all other components not connected. However, when I
tried clearing the BIOS again with the new PSU, the computer then
booted fine. I ran it for a full two minutes without any problems.

I then tried adding components one-by-one with the Trust PSU inserted.
Sadly I only got as far as the CPU before the reboot problem came
back. I have noticed that the CPU fan, even when it is running, is
spinning very slowly. I have a molex adapter somewhere, so I'll try
and bypass any fan speed control on the motherboard.

Kind Regards,

Matt

At this point, my only comment would be that you're dealing with
two problems. Maybe the original power supply has a problem.
And the Trust is OK.

Your second issue, might be the version of BIOS used on the board.
You could try some older LGA775 processor in it, and see if
it stays running. Or (somehow) determine what BIOS version is
present in the BIOS chip.

Also, could you post the exact and complete model number for
the Gigabyte motherboard (as they have more than one with X48) ?
Maybe I can find some reviews, and see if they have matching symptoms.

Paul
 
M

Matt

At this point, my only comment would be that you're dealing with
two problems. Maybe the original power supply has a problem.
And the Trust is OK.

The only way to be sure would to try the bew PSU in my current
computer, but I'm not willing to try that at the moment and break two
computers!
Your second issue, might be the version of BIOS used on the board.
You could try some older LGA775 processor in it, and see if
it stays running. Or (somehow) determine what BIOS version is
present in the BIOS chip.

Sadly I don't have another LGA775 CPU around that I could use.

As for the BIOS version I can't say what version I have.
Also, could you post the exact and complete model number for
the Gigabyte motherboard (as they have more than one with X48) ?
Maybe I can find some reviews, and see if they have matching symptoms.

I have the Gigabyte GA-X48-DS4 Revision 1.3.

Kind Regards,

Matt
 
P

Paul

Matt said:
The only way to be sure would to try the bew PSU in my current
computer, but I'm not willing to try that at the moment and break two
computers!


Sadly I don't have another LGA775 CPU around that I could use.

As for the BIOS version I can't say what version I have.


I have the Gigabyte GA-X48-DS4 Revision 1.3.

Kind Regards,

Matt

There are some similar symptoms described here. One related to RAM
stick placement. The other appears to be a motherboard issue. One
person suggests the reboot loop is caused by the board flipping
back and forth between the dual BIOS images. So there are a
few unhappy campers here.

http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16813128336

Paul
 
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M

Matt

Thanks for the link, it's good to know I'm not the first person to
suffer from this problem.

Having tested the PSU in a different computer (and finding it to be
faulty) I will definately be getting a replacement. In addition, since
the reboot cycle occurs when the good PSU, CPU and motherboard are
installed, I will be returning the motherboard and CPU, as I can't pin
down which of the two is at fault.

This is because either the CPU is at fault, as the motherboard and
Trust PSU operate fine on their own; or the motherboard (more
specifically the BIOS) is at fault as once the CPU is installed, the
motherboard can begin to boot and read from the BIOS. This then causes
the computer to turn off. It may even be both motherboard and CPU that
are faulty!

Anyway thanks for the help today. Here's hoping for a speedy returns
process!

Kind Regards,

Matt
 

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