GIGABYTE GA-965P-DS3 Power cycle problem

Ok...I am putting together a new system and having issues that I can't
figure out.

Specs:
GIGABYTE GA-965P-DS3 MoBo
Core 2 Duo E6300
2gb Corsair XMS2 PC2 6400
256mb Sapphire X1900XT
600w Enermax SLI PSU

When I power it on the PSU cycles on and off like there is a short. It
simply goes on, then off after a second or so, then pauses, then turns
itself back on...and so on until I turn the power off.

I have checked connections and plugs, re-seated the processor
etc...same issue.

When I REMOVE the 4pin 12v CPU power from the MoBo - the PSU will run
constantly (of course I don't get a boot sequence because the CPU is
not powered up).

The 4pin 12v power is run off an adapter from one of my 8pin leads from
the PSU.

Seems like the trouble lies in the 4pin connection - either I shouldn't
be using that adapter or it is shorted...

I have seen a few threads in various places about the DS3 having this
EXACT issue but haven't seen a fix. HELP!

Removing the 4-pin ATX power supply from the motherboard can damage the
CPU. DO NOT DO THAT. When you do that, the CPU is getting some of it's
power from some pins, while other power supplies that it needs don't
have power. Very, very bad thing to do.

Power cycling like this ONCE is "normal" according to Gigabyte.

Try removing ONE memory module (leaving only one module) and see if that
helps (UNPLUG the power supply first, and wait 30 seconds).

If you are using an adapter to get the ATX 12V, then you have an ancient
and inadequate power supply. Replace the power supply with a quality
supply that puts out at least 400 watts and at least 20 amps on the 12
volt rails. I suspect that this is your real problem, but your attempts
to "fix" it might have caused damage that wasn't originally present.


Gordo282 wrote:

> Ok...I am putting together a new system and having issues that I can't
> figure out.
>
> Specs:
> GIGABYTE GA-965P-DS3 MoBo
> Core 2 Duo E6300
> 2gb Corsair XMS2 PC2 6400
> 256mb Sapphire X1900XT
> 600w Enermax SLI PSU
>
> When I power it on the PSU cycles on and off like there is a short. It
> simply goes on, then off after a second or so, then pauses, then turns
> itself back on...and so on until I turn the power off.
>
> I have checked connections and plugs, re-seated the processor
> etc...same issue.
>
> When I REMOVE the 4pin 12v CPU power from the MoBo - the PSU will run
> constantly (of course I don't get a boot sequence because the CPU is
> not powered up).
>
> The 4pin 12v power is run off an adapter from one of my 8pin leads from
> the PSU.
>
> Seems like the trouble lies in the 4pin connection - either I shouldn't
> be using that adapter or it is shorted...
>
> I have seen a few threads in various places about the DS3 having this
> EXACT issue but haven't seen a fix. HELP!
>

It sounds like a power a supply issue or possibly a case short. As
previously noted, make certain your power supply is suitable for this MB.

Other thoughts:
Your memory is probably 2.1V and the MB is set to 1.8; this can be a
problem with F1 and F2 bios revisions on this MB

If you have ruled out the case/short and power supply, disable the
Gigabyte controller in the bios and unplug all hard drives from the ICH8
controller. Incompatibility between the ICH8 and certain hard dives will
actually cause cyclic rebooting; the Maxtor 6B300S0 with any firmware
revision on any ICH8 channel is a good example of this problem.

Are you using the 12V 4-pin Molex power connector 16x PCIe slot?

Barry Watzman wrote:
> Removing the 4-pin ATX power supply from the motherboard can damage the
> CPU. DO NOT DO THAT. When you do that, the CPU is getting some of it's
> power from some pins, while other power supplies that it needs don't
> have power. Very, very bad thing to do.
>
> Power cycling like this ONCE is "normal" according to Gigabyte.
>
> Try removing ONE memory module (leaving only one module) and see if that
> helps (UNPLUG the power supply first, and wait 30 seconds).
>
> If you are using an adapter to get the ATX 12V, then you have an ancient
> and inadequate power supply. Replace the power supply with a quality
> supply that puts out at least 400 watts and at least 20 amps on the 12
> volt rails. I suspect that this is your real problem, but your attempts
> to "fix" it might have caused damage that wasn't originally present.
>
>
> Gordo282 wrote:
>
>> Ok...I am putting together a new system and having issues that I can't
>> figure out.
>>
>> Specs:
>> GIGABYTE GA-965P-DS3 MoBo
>> Core 2 Duo E6300
>> 2gb Corsair XMS2 PC2 6400
>> 256mb Sapphire X1900XT
>> 600w Enermax SLI PSU
>>
>> When I power it on the PSU cycles on and off like there is a short. It
>> simply goes on, then off after a second or so, then pauses, then turns
>> itself back on...and so on until I turn the power off.
>>
>> I have checked connections and plugs, re-seated the processor
>> etc...same issue.
>>
>> When I REMOVE the 4pin 12v CPU power from the MoBo - the PSU will run
>> constantly (of course I don't get a boot sequence because the CPU is
>> not powered up).
>>
>> The 4pin 12v power is run off an adapter from one of my 8pin leads from
>> the PSU.
>>
>> Seems like the trouble lies in the 4pin connection - either I shouldn't
>> be using that adapter or it is shorted...
>>
>> I have seen a few threads in various places about the DS3 having this
>> EXACT issue but haven't seen a fix. HELP!
>>

So I had this problem today as well. Last night the power surged at my condo twice in a row, I woke up to find my computer doing this same power cycle thing, and started to troubleshoot. I unplugged all hard drives, and down to a stick of ram vs 4. Still same problem. Cleared the CMOS, now instead of just a power cycle problem, I also get a series of fast beeps, and the power cycle problem. Hmmm I just cleared the CMOS, take the battery completely out. Boot, same stuff, same beeps. Maybe the battery is dead? Trip to radio shack, new battery on the CMOS, same problem. So I start 'exchanging' the remaining sticks of ram with the one in there. Boot, no power cycle, no beeps, boots fine. Post asks to use the last known good BIOS settings. I boot up and down several times trying to get my 4 gigs back, and have determined that one of the sticks went bad overnight during the power surges. Lesson learned: Be sure to plug pc into a good ups. Hope this helps.

Same problem here.

System has been stable for 2 years, now it won't boot. Does not reach POST. Fans spin up, lights on, but then all is shut down within say 3-5 seconds. If I don't switch off power supply this continues forever, up and down.
Checked board for blown capacitors, couldn't find any. Als checked cables and so forth.
No hardware changes for quite a while.

With the indication in the prvious post I check the memory, reseated them, then uninstalled one, then the other, switched location. No changes.

Seems I might have to uninstall everything and reseat all components.
Could it be the power supply? How would I know?

MoBo: Gigabyte 935-DS3
Power: iGreenPower 600W

Much appreciate any help.

Follow up:

I bought a new PS, which didn't make any difference
(At least I used the new PS to build a new PC now... )

I then unplugged the entire PC, mobo, RAM, video, everything.
Then put it back together, nothing.

Then removed CPU and heatsink; removed grease and put new, reseated all, still the same.

I checked both Mobo and CPU for any damage, nothing.


Anyone any idea?