evga 750 watt psu wont work with new mobo

[vampirenight721]

i just got a new motherboard and cpu today and i can not seem to get it working with my evga supernova g2 750. the system power flickers and will not start and the psu does work with other motherboards and the motherboard in question works with other psus. atm i have jumped the 24pin on my 750 watt psu to power my rx580 and im using a 500 watt unit to power the board and a xeon e5 2680. also id like to mention that yes this is a chinese motherboard but the problem im having is very strange to say the least as the board has powered up no problems with 2 different psus and my evga unit has no issues powering other motherboards like my dell xps studio 9100 motherboard which has a i7 990x in it. if anyone has any tips on what i can try to get this combo to work please let me know as i dont have the money to get a new power supply. also id like to add that i have fully ruled out any shorts on the board.

 

edit: turns out its the motherboard as i tested 2 different power supplies 1 being a corsair 800 watt and a xfx 1250 watt unit and the 800 watt didnt even try and the 1250 watt unit started but once we shut it down to restart it the psu then wouldnt start.

[Guest]

PSU works with other motherboards.

 

Motherboard works with other PSUs.

 

So forgive me for asking the obvious:  The motherboard, when it works, is still mounted to this same case/motherboard tray?

 

The PSU is using the cables that came with it?

 

When you "test" it with multiple motherboards, are you also plugging in additional devices like SSD, HDD, ODD, LED's, etc. (because a short in any of these would cause the PSU to "latch off" and stop providing power).

 

[vampirenight721]

2 minutes ago, jonnyGURU said:

PSU works with other motherboards.

 

Motherboard works with other PSUs.

 

So forgive me for asking the obvious:  The motherboard, when it works, is still mounted to this same case/motherboard tray?

 

The PSU is using the cables that came with it?

 

When you "test" it with multiple motherboards, are you also plugging in additional devices like SSD, HDD, ODD, LED's, etc. (because a short in any of these would cause the PSU to "latch off" and stop providing power).

 

when i was testing it i had the motherboard out on a box with just the the 24 pin hooked up and it did the same thing and im questioning the short but im not sure because ive pulled everything off the board even the heatsyncs and it still power flickers

[Guest]

1 minute ago, vampirenight721 said:

when i was testing it i had the motherboard out on a box with just the the 24 pin hooked up and it did the same thing and im questioning the short but im not sure because ive pulled everything off the board even the heatsyncs and it still power flickers

Hmm.. Ok.  That's the way I would do it.  Bare essentials, not mounted, on a box.  If you're using the cables that came with the PSU and it still doesn't work, could just be a dead PSU.

 

The PSU came with a simple "tester".  What happens when you use it?  Does the PSU actually fire up?

 

[vampirenight721]

4 minutes ago, jonnyGURU said:

Hmm.. Ok.  That's the way I would do it.  Bare essentials, not mounted, on a box.  If you're using the cables that came with the PSU and it still doesn't work, could just be a dead PSU.

 

The PSU came with a simple "tester".  What happens when you use it?  Does the PSU actually fire up?

 

yes in fact im using the psu to power the cpu, gpu and storage which consist of a ssd and hdd and im in windows the only connectro im not using from my 750 watt unit is the 24 pin

[vampirenight721]

20 minutes ago, jonnyGURU said:

Hmm.. Ok.  That's the way I would do it.  Bare essentials, not mounted, on a box.  If you're using the cables that came with the PSU and it still doesn't work, could just be a dead PSU.

 

The PSU came with a simple "tester".  What happens when you use it?  Does the PSU actually fire up?

 

it makes 0 sense because the system is running and it score 1100 on cinibench r15

[Guest]

3 hours ago, vampirenight721 said:

it makes 0 sense because the system is running and it score 1100 on cinibench r15

Well.. That factoid means nothing.  PSU quality isn't going to impact your Cinebench score.  It's either going to work or it doesn't.  And right now, it works on one board, but not another.

 

[vampirenight721]

1 hour ago, jonnyGURU said:

Well.. That factoid means nothing.  PSU quality isn't going to impact your Cinebench score.  It's either going to work or it doesn't.  And right now, it works on one board, but not another.

 

no i was using the 750 watt unit to power the cpu and gpu as well as the drives and i had no issues but if i had to guess the motherboard could be causing the short protection to trip but then again my dell psu that i know has short protection dosnt trip

[vampirenight721]

1 hour ago, jonnyGURU said:

Well.. That factoid means nothing.  PSU quality isn't going to impact your Cinebench score.  It's either going to work or it doesn't.  And right now, it works on one board, but not another.

 

theres a chance i might know what it is and that being i remember doing research on the chinese motherboards before and i saw something about theyre sensors not being set up so they show insane temps and idk if this could cause my psu to do what its doing but anything is possible at this point.

[Spotty]

7 minutes ago, vampirenight721 said:

theres a chance i might know what it is and that being i remember doing research on the chinese motherboards before and i saw something about theyre sensors not being set up so they show insane temps and idk if this could cause my psu to do what its doing but anything is possible at this point.

No, your PSU doesn't care about the motherboard temperatures.

How are you starting the PC btw? Just sticking a metal object (key, screwdriver, etc) in between the front panel connector PWR pins on the motherboard? Or some other way?

 

With your EVGA 750 G2 on the PSU side do you have both of the connectors for the 24pin motherboard cable plugged in to the PSU? There's a long 18pin plug and shorter 10pin plug which both need to be plugged in on the PSU side.

[comicsansms]

5 hours ago, vampirenight721 said:

The system power flickers and will not start and the psu does work with other motherboards and the motherboard in question works with other psus.

What are the other PSUs?

5 hours ago, vampirenight721 said:

I'd like to mention that yes this is a chinese motherboard but the problem im having is very strange to say the least as the board has powered up no problems with 2 different psus and my evga unit has no issues powering other motherboards like my dell xps studio 9100 motherboard which has a i7 990x in it.

What's the motherboard?

5 hours ago, vampirenight721 said:

If anyone has any tips on what i can try to get this combo to work please let me know as i dont have the money to get a new power supply. also id like to add that i have fully ruled out any shorts on the board.

If you have a dodgy, no-name motherboard, the bios may not be 100% to ATX spec. That being said, that doesn't necessarily mean that's where the problem is.

[vampirenight721]

21 minutes ago, Spotty said:

No, your PSU doesn't care about the motherboard temperatures.

How are you starting the PC btw? Just sticking a metal object (key, screwdriver, etc) in between the front panel connector PWR pins on the motherboard? Or some other way?

 

With your EVGA 750 G2 on the PSU side do you have both of the connectors for the 24pin motherboard cable plugged in to the PSU? There's a long 18pin plug and shorter 10pin plug which both need to be plugged in on the PSU side.

yes both are pluged into the psu side as that was the first thing i checked and i have been shorting the connectors to start the board as its no longer in a case

[vampirenight721]

22 minutes ago, Comic_Sans_MS said:

What are the other PSUs?

What's the motherboard?

If you have a dodgy, no-name motherboard, the bios may not be 100% to ATX spec. That being said, that doesn't necessarily mean that's where the problem is.

it has a regular bios and from what ive seen the board is pretty high quality as my xeon e5 2680 was turboing on all cores up to 3.1 and the vrms wernt getting that hot

[comicsansms]

1 minute ago, vampirenight721 said:

it has a regular bios and from what ive seen the board is pretty high quality as my xeon e5 2680 was turboing on all cores up to 3.1 and the vrms wernt getting that hot

Answer my questions...

[vampirenight721]

4 minutes ago, Comic_Sans_MS said:

Answer my questions...

sorry didnt see those. the board is a jingsha x79-p3 and the other psu is a cheap knock off unit by hydra that being 500 watts. ive been using the 20 pin connector to power the board and all other connectors from my evga power supply to supply the system with power and this is how i ran it in order to get into the bios and into windows.

[comicsansms]

7 minutes ago, vampirenight721 said:

sorry didnt see those. the board is a jingsha x79-p3 and the other psu is a cheap knock off unit by hydra that being 500 watts. ive been using the 20 pin connector to power the board and all other connectors from my evga power supply to supply the system with power and this is how i ran it in order to get into the bios and into windows.

Can you try the motherboard on another good PSU?

 

Also, what happens with the G2 and the Jingsha X79-P3 motherboard? Does the motherboard turn on, but the computer not POST? Or does the PSU make a clunk sound, and immediately turn off, when you try to turn on?

[vampirenight721]

16 minutes ago, Comic_Sans_MS said:

Can you try the motherboard on another good PSU?

 

Also, what happens with the G2 and the Jingsha X79-P3 motherboard? Does the motherboard turn on, but the computer not POST? Or does the PSU make a clunk sound, and immediately turn off, when you try to turn on?

i was going to run down to a computer store today that has test units so i could test the system with another unit also when i did some research i found that im not the only one who has had this kind of issue with evga psus. also to answer the question no it just power flickers so everything like the leds and the post code light comes on for a split second then shuts off and its not even enough to move the fans.

[vampirenight721]

21 minutes ago, Comic_Sans_MS said:

Can you try the motherboard on another good PSU?

 

Also, what happens with the G2 and the Jingsha X79-P3 motherboard? Does the motherboard turn on, but the computer not POST? Or does the PSU make a clunk sound, and immediately turn off, when you try to turn on?

also i did notice a strange noise when it does shut off it kinda sounds like someone taps the outside of the unit with a finger nail

[comicsansms]

3 hours ago, vampirenight721 said:

also i did notice a strange noise when it does shut off it kinda sounds like someone taps the outside of the unit with a finger nail

So relays, so that sounds like the PSU is shutting off as a safety precaution. I think there's something not right with your motherboard.

[vampirenight721]

1 hour ago, Comic_Sans_MS said:

So relays, so that sounds like the PSU is shutting off as a safety precaution. I think there's something not right with your motherboard.

im not sure i think its short circuit protection but the board works perfectly fine also there is a chance it could be over voltage protection because of the chipset and whatnot but who knows

[Guest]

It's probably just an issue with the power good signal timing.

 

Used to see this all the time.  If the T3 signal is too long, the board won't feedback a power good signal and the PSU will never turn on.

 

[vampirenight721]

7 hours ago, jonnyGURU said:

It's probably just an issue with the power good signal timing.

 

Used to see this all the time.  If the T3 signal is too long, the board won't feedback a power good signal and the PSU will never turn on.

 

i got it to work with the psu but i wouldnt do it as it can really shorten the life span of the power supply and that is if i kept shorting the reset cmos pins it will turn on but like i said its not very good for the psu but i was able to get a cinibench run and a 3d mark run with my ram overclocked to 1866mhz and the system scored 12000 on firestrike dx11 and the cinibench score didnt change much as it scored a 1078

[vampirenight721]

7 hours ago, jonnyGURU said:

It's probably just an issue with the power good signal timing.

 

Used to see this all the time.  If the T3 signal is too long, the board won't feedback a power good signal and the PSU will never turn on.

 

this seems very likely because what happens when i short the power pins on the board is that the psu will not attempt a start up a second time until i shut the unit down and wait for about 5 seconds to hear the capacitors discharge. im just wondering saying that this is in fact a chinese motherboard is if the power is unstable when the system fully starts and the only way i can think of getting around the power good signal is somehow getting 5 volts to be present long enough for the board to start.

[vampirenight721]

8 hours ago, jonnyGURU said:

It's probably just an issue with the power good signal timing.

 

Used to see this all the time.  If the T3 signal is too long, the board won't feedback a power good signal and the PSU will never turn on.

 

ok after a solid half hour of research and a bit of testing it is the power ok line as it was only generating 1.3 volts when i started the system and when i spamed the bios reset i was able to push the voltage up the 3 volts which then alowed the system to start on next voltage spike