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First post, by 386SX

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Hi,
I'm trying some different 20pin power supply on a 24pin motherboard (supporting dual core intel / ddr2) leaving the last 4 pin of the mobo connector obviously open. I read somewhere that beside some heavy power requirements it should still boot so I used a 1,65ghz low power dual core cpu but no way, the fan seems to move a bit and then it stops.
Do you think I still need a 24pin power supply or I can use these P4 20pin ones anyway? Or I need the converter cable?
Thank

Reply 1 of 9, by LR35902

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Just to be sure, is there a 4 pin cpu power connector on the board?

Reply 2 of 9, by 386SX

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LR35902 wrote:

Just to be sure, is there a 4 pin cpu power connector on the board?

On the mobo there's the usual 24pin atx connector and separately the 4 pin 12v connector too. 😉

Reply 3 of 9, by havli

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Yes, 20pin will work just fine.

HW museum.cz - my collection of PC hardware

Reply 4 of 9, by 386SX

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havli wrote:

Yes, 20pin will work just fine.

This make me think something is wrong with the mobo cause there's no way. I tried also a powerful Enermax 20pin for Athlon XPs.

Reply 5 of 9, by 386SX

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It looks like there's something wrong with the board a MSI MS-7525 on socket 775. With a 24pin power supply it still can't boot. The fan move a bit and then stop.

Reply 6 of 9, by .legaCy

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The 4 pin power connector that sits right next to the cpu is connected right?
Just to be sure that is connected properly you can wiggle it in a little bit.
Is there anything that may cause short circuits like those metal stand offs in the case?

Reply 7 of 9, by 386SX

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.legaCy wrote:

The 4 pin power connector that sits right next to the cpu is connected right?
Just to be sure that is connected properly you can wiggle it in a little bit.
Is there anything that may cause short circuits like those metal stand offs in the case?

The connector is stable and the mobo is outside the case with just the cpu and ram. Maybe some components failed and causing this?

Reply 8 of 9, by SW-SSG

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It does sound like something on the board is shorted.

Without the 4-pin ATX12V attached, it should power on (fans spinning and etc) but not POST... at least in my experience.

Reply 9 of 9, by .legaCy

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386SX wrote:
.legaCy wrote:

The 4 pin power connector that sits right next to the cpu is connected right?
Just to be sure that is connected properly you can wiggle it in a little bit.
Is there anything that may cause short circuits like those metal stand offs in the case?

The connector is stable and the mobo is outside the case with just the cpu and ram. Maybe some components failed and causing this?

Well maybe failing mosfets or mosfet drivers, if you can diagnose the vrm part of the board.
This happened to me twice, one was a shorted motherboard(thankfully the psu protection prevented the motherboard to be fried, removing the short brought it back) and other was bad fets on the board.