Two new PSUs don’t work, old one does.

[Underi]

I’m completely at my wits end. I have a 2017 built system with a MSI Z370 PC PRO motherboard and previously had a GTX 970 and a Seasonic S12ii-520 PSU. Yesterday evening I decided to upgrade and bought a 3070 and a be quiet dark power 12 1000W. After work I got home, replaced the parts and nothing. 
 

I’ve been troubleshooting the whole last night. I came to the conclusion that the PSU is faulty since I tested with just the motherboard, RAM, CPU and PSU connected and it didn’t work unless I connected my older Seasonic. I went back to the store an hour ago, RMA’d the bequiet and took a Seasonic GX-1000 back with me. Well guess what. Same thing. It doesnt work, except if I short the green and black pin while the 24pin is connected to the mobo. Everything fires up and EZ debug CPU led lights up. Shuts down as soon as I let go. This doesn’t happen with the old 520w seasonic. What the hell could be wrong here? Why would it work with one PSU and not others? If the motherboard was faulty why would it work at all? What’s the variable here???

[Aragorn-]

have you reused any modular cables? 

 

defo connected the 4/8pin CPU power using the correct CPU cable, not a PCIe one?

[Underi]

2 minutes ago, Aragorn- said:

have you reused any modular cables? 

 

defo connected the 4/8pin CPU power using the correct CPU cable, not a PCIe one?

No I have not, this is my first modular supply. And yes the cables are correct.

[mariushm]

Change ALL modular cables, they're not compatible between brands or even models from same manufacturer.

Make sure the 24 pin connector is fully inserted - slide a couple of fingers under the motherboard so that when you press down on the connector you don't bend motherboard too much.

Make sure the cpu connector is fully plugged in.

Make sure the on/off switch in the back of the power supply is in the ON position.

 

[Aragorn-]

two faulty PSU seems unlikely, though i guess not impossible.

 

Does the 3070 work with the 520w?

[Underi]

2 minutes ago, mariushm said:

Change ALL modular cables, they're not compatible between brands or even models from same manufacturer.

Make sure the 24 pin connector is fully inserted - slide a couple of fingers under the motherboard so that when you press down on the connector you don't bend motherboard too much.

Make sure the cpu connector is fully plugged in.

Make sure the on/off switch in the back of the power supply is in the ON position.

 

Well you clearly didn’t read my messages. This is my first modular supply, I do not have any other cables than the ones the power supply came with.

 

3 minutes ago, Aragorn- said:

two faulty PSU seems unlikely, though i guess not impossible.

 

Does the 3070 work with the 520w?

Haven’t tried since it’s not enough to game anyways. Will do now.

[Underi]

9 minutes ago, Aragorn- said:

two faulty PSU seems unlikely, though i guess not impossible.

 

Does the 3070 work with the 520w?

Yeah it works. 

[Aragorn-]

i mean the only logical answer is either both the new psu's were duds, or they werent connected properly.

[Underi]

3 minutes ago, Aragorn- said:

i mean the only logical answer is either both the new psu's were duds, or they werent connected properly.

Well the new seasonic did work in an another system I tried, but if the motherboard was faulty what makes it work with one psu and not others?

[Underi]

Got it to start by shorting PS_ON for a minute or so until the CPU debug LED disappeared. Power switch still doesn't work.

[Gazereths]

I know some newer power supplies have changed spec slightly, the PG (POWER GOOD) signal has reduced to ~80 milliseconds which causes errors on the generic power supply testers.

 

ATX spec says it should be no shorter than 100ms and no longer then 500ms.

 

Whether this would have any affect on a slightly older board is unknown to me though. I have one with an 80ms PG signal that workks on an older a320 / 3200g combo. Whether Intel boards are different...who knows? @jonnyGURU??

[Guest]

6 hours ago, Gazereths said:

I know some newer power supplies have changed spec slightly, the PG (POWER GOOD) signal has reduced to ~80 milliseconds which causes errors on the generic power supply testers.

 

ATX spec says it should be no shorter than 100ms and no longer then 500ms.

 

Whether this would have any affect on a slightly older board is unknown to me though. I have one with an 80ms PG signal that workks on an older a320 / 3200g combo. Whether Intel boards are different...who knows? @jonnyGURU??

You could very well be correct.  

[Guest]

11 hours ago, Underi said:

It doesnt work, except if I short the green and black pin while the 24pin is connected to the mobo.

 

Everything fires up and EZ debug CPU led lights up. 

2 part ideas for you.

 

The first one, I'd be checking the power switch. They do go bad on accessions and sometimes not the greatest of connectors imo.

 

The second one, clearing cmos when making ANY hardware changes might be a good idea.

 

Again, I don't know if this is a "fix" or not, just a couple of ideas. Good Luck!

[Underi]

23 hours ago, Guest 5150 said:

2 part ideas for you.

 

The first one, I'd be checking the power switch. They do go bad on accessions and sometimes not the greatest of connectors imo.

 

The second one, clearing cmos when making ANY hardware changes might be a good idea.

 

Again, I don't know if this is a "fix" or not, just a couple of ideas. Good Luck!

Yeah I had tried those before making the post here. The switch being faulty wouldnt matter cuz I tried to start by shorting the switch pins on the mobo anyways.