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Old 06-28-2017, 06:38 AM   #1
ATB57791
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Default Asus P6T Deluxe does not power on

Hi! I have a P6T Deluxe motherboard from Asus that does not power on at all. I tried to short the power on pins on the motherboard with a jumper and also tried the included power switch and neither of them does anything.
However, if I short the green and black wires from the ATX connector the motherboard powers up normally and even boots Windows 7.
I measured that the voltage between the PWR and ground pin is 3.3V when the motherboard is off and PSU connected.
Do you have any idea what is wrong with the motherboard or which components should I try to replace?
Pictures of the motherboard attached.
Attached Images
File Type: jpg P6T.jpg (1.37 MB, 40 views)
File Type: jpg P6T_2.jpg (1.36 MB, 29 views)
File Type: jpg P6T_3.jpg (1.11 MB, 30 views)
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Old 07-01-2017, 01:29 AM   #2
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Default Re: Asus P6T Deluxe does not power on

Should not PWR_OK be 5v?
If so maybe it means the PSU itself is bad (or just it's PWR_OK signal).
Did you try another PSU?
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Old 07-02-2017, 08:51 AM   #3
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Default Re: Asus P6T Deluxe does not power on

I have tested the motherboard with three known working PSUs.
I assume that the 3.3V stand by voltage comes from ME1117 voltage regulator. I measured the pads when 5VSB is fed to the motherboard and they looked OK in my opinion. The voltage on the other power button pin is 3.39V and the other one is ground.
The 5VSB voltage from psu is 5.00V. According to my knowledge the PWR_OK signal is only on when the PSU is on.
The problem here is that the motherboard does not start the PSU when I push the power button.
Attached Images
File Type: jpg P6T_4.jpg (896.3 KB, 17 views)
File Type: jpg 1117.jpg (164.2 KB, 13 views)
File Type: jpg power button pin.jpg (167.4 KB, 12 views)

Last edited by ATB57791; 07-02-2017 at 09:21 AM..
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Old 07-02-2017, 09:18 AM   #4
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Default Re: Asus P6T Deluxe does not power on

Yes, but 5VSB is not related to the PWR_OK signal.
Check the pinout here: http://pinouts.ru/Power/atx_v2_pinout.shtml
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Old 07-02-2017, 09:26 AM   #5
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Default Re: Asus P6T Deluxe does not power on

I have not measured the PWR_OK signal. I meant that the pins on the motherboard that get shorted when you press the power button are 3.3V, sorry for being unclear. The PSU that I'm using is tested and working.
The motherboard starts only if I jump-start the power supply. So I am trying to find out why the motherboard does not short the PS_ON pin in the ATX connector when I push the power button.

Last edited by ATB57791; 07-02-2017 at 09:31 AM..
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Old 07-02-2017, 10:25 AM   #6
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Default Re: Asus P6T Deluxe does not power on

The LPC Super IO chip is usually responsible for turning on the PSU.

On your board, the Super IO (SIO) should be that Winbond chip in the lower left corner. Can you post its part number? I can't seem to fully read it from your pictures. Looks like W83____HG-A

Around 3.3V on the Power Switch button on the motherboard is normal.

By the way, any chance the LAN chip gets hot when the PSU is plugged in the motherboard? A lot of times, a lightning strike can take out / damage the LAN chip, and sometimes also the SIO.
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Old 07-02-2017, 12:18 PM   #7
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Default Re: Asus P6T Deluxe does not power on

The Super IO chip is Winbond W83667HG-A
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Old 07-02-2017, 12:53 PM   #8
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Default Re: Asus P6T Deluxe does not power on

I booted the motherboard by jump starting the PSU. This time it took a few times until it booted successfully. Neither of the two Marvell's LAN chips (88E8056) were warm. The Marvell 88SE6320 SAS controller and 88SE6111 IDE controller were both a bit warm, but not too hot to touch. The Super IO chip was maybe just a little warm if not at all.
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Old 07-04-2017, 07:21 PM   #9
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Default Re: Asus P6T Deluxe does not power on

Quote:
Originally Posted by ATB57791 View Post
The Super IO chip is Winbond W83667HG-A
Welp...
I looked at its datasheet, and unfortunately, it looks like this Winbond chip does not control any of the motherboard's power functions.

... so whatever is controlling the power, it's not the Super IO. Might be the Southbridge then, unless you can trace the power switch header on the motherboard and see where the traces go. Perhaps there may be another chip just responsible for power functions.
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Old 07-06-2017, 05:04 AM   #10
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Default Re: Asus P6T Deluxe does not power on

This might not be the case to your board but yesterday i had an MSI Z77A-G43 doing exactly the same, i shorted the psu, went into bios and updated it to the latest and after that it is all good to boot on its own, i dont know if it will help but there's no harm in trying
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Old 07-06-2017, 09:07 AM   #11
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Default Re: Asus P6T Deluxe does not power on

Quote:
Originally Posted by ScorpioMan86 View Post
This might not be the case to your board but yesterday i had an MSI Z77A-G43 doing exactly the same, i shorted the psu, went into bios and updated it to the latest and after that it is all good to boot on its own, i dont know if it will help but there's no harm in trying
Good point!

Actually now that you reminded me, we also had several board at work before that acted in a similar way. For those, however, they had socketed dual BIOSes. Switching to the other BIOS typically solved the issue.

So yes, try what ScorpioMan86 mentioned.
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Old 07-06-2017, 12:50 PM   #12
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Default Re: Asus P6T Deluxe does not power on

The motherboard already had the newest bios (2209) installed so I downgraded the bios to 2101 but still it doesn't start on its own.
I also figured out why it didn't start with first try previously. I have to short the green and black wires on the ATX connector and also push the power button to start the motherboard.
I presume that the motherboard tries to start but somehow the circuit that would normally short the green and black wire doesn't work.

Edit: Also upgraded back to 2209 bios with no change.

Last edited by ATB57791; 07-06-2017 at 12:59 PM..
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Old 02-12-2018, 03:48 PM   #13
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Default Re: Asus P6T Deluxe does not power on

There is another option (although it seems a bit late I saw the topic ...)
Close the green and black contacts with tweezers or wires, when the board starts up and displays information about the processor, memory, etc., close the power_on with tweezers or even for a second and the board should shut down (unless of course winbond did not die at all), then open the green and black contacts on the power supply connector and try to run as usual on power_on

On MSI boards, this operation helped to restore the normal start
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Old 02-12-2018, 09:26 PM   #14
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Default Re: Asus P6T Deluxe does not power on

Quote:
Originally Posted by momaka View Post
Welp...
I looked at its datasheet, and unfortunately, it looks like this Winbond chip does not control any of the motherboard's power functions.

... so whatever is controlling the power, it's not the Super IO. Might be the Southbridge then, unless you can trace the power switch header on the motherboard and see where the traces go. Perhaps there may be another chip just responsible for power functions.
my guess would be that ASUS APU Chip next to the BIOS Chip.
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Old 02-13-2018, 03:02 PM   #15
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Default Re: Asus P6T Deluxe does not power on

Power on is handled by the EC, the Winbond chip. Power states are handled by the southbridge, but the EC gives the initial startup signal (RSMRST then PWRBTN) to the southbridge.
Boardview of P6T attached if it helps.
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File Type: zip P6T_1.01G.fz.zip (146.5 KB, 14 views)
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Old 02-14-2018, 01:24 PM   #16
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Default Re: Asus P6T Deluxe does not power on

Very good chance that one of the FET's under the skinny blue heatsink that is NOT connected to the heat pipe has gone bad.
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Old 06-06-2018, 10:43 AM   #17
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Default Re: Asus P6T Deluxe does not power on

I replaced the Super IO chip (W83667HG-A) on the motherboard and now it powers on normally. The power and reset buttons on the motherboard don't work, but it is not a big issue because the chassis power button is working.

Last edited by ATB57791; 06-06-2018 at 10:47 AM..
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Old 06-09-2018, 03:41 PM   #18
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Default Re: Asus P6T Deluxe does not power on

Awesome! Great to hear you got it sorted out and thanks for coming back to update us on the matter! I'm sure many others will find this info helpful too.
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