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Low power system not booting with high efficiency PSU?!
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Author:  Bluefront [ Sun Nov 18, 2007 9:00 pm ]
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maybe.....get a 12v auto bulb socket from an auto parts store. Use a 20w bulb. Hook it to the yellow and black wires from a spare molex connector. That will answer your question.

My fortron needs at least 8w hooked up like this to boot.

Author:  mr pink [ Tue Nov 20, 2007 1:11 pm ]
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Now I'm worried. I just ordered a 380w earthwatts for my asus m2a-vm.

Newegg has a $30 rebate , by the way - I will post my results!

Author:  mr pink [ Wed Nov 21, 2007 5:22 pm ]
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It works! I do have an x1300 card in there though. Funny, I tried an earthwatts 430 last month and it displayed the problem discussed here.

Author:  Drexl [ Mon Mar 03, 2008 11:41 pm ]
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I wonder if this is related to my Corsair 520hx crapping out after about six months of use.

About a month or so ago, the system started not coming back from a suspended state. I would see the DVD drive's light come on, and if I got close to it I could hear it trying to start up, but it would stop. A reboot would work, although I would have to disconnect the power and connect again to get it to come on.

Then, the other day, the computer just shut off while I was using it. I was reading a web page, and I think something was being downloaded as well, so it couldn't have been completely idle. It would not boot again, so I opened the case to inspect it. When I would turn the power on, the CPU and PSU fans would come on for a few seconds and then stop. So now, I'm pretty sure it's the PSU.

I don't know if this issue is the reason, since my system isn't exactly minimalist; I have a PCIe video card (though it's a passive 8500GT), an overclocked dual-core CPU, and 4GB of RAM.

Anyway, I'm looking for a new PSU to get it going again, and I'm considering the Seasonic S12 II 380. However, I'm nervous because it's very similar to the one I had.

Author:  ginahoy [ Sun Mar 09, 2008 10:33 am ]
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FWIW, I was concerned about this issue...

I just built a PC around a 939 mobo (ASUS A8V Deluxe) and wanted to use the Seasonic S12 II 330. I can report that this combination boots fine without mods. My video card is a Sparkle 7600 GS (passive).

David

Author:  kickaha [ Sun May 25, 2008 5:07 pm ]
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Thank again SPCR for this thread.

PicoPSU 120W + Asus M2A-VM HDMI + AMD 4850E doesn't bootstrap.
I had to add just a WD 2.5" hard drive to make it work.

Author:  Drexl [ Sun May 25, 2008 8:39 pm ]
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Oh, I forgot about this. Disregard my post above.

The power supply was fine. The problem was eventually traced to a bad stick of RAM.

Author:  lutorm [ Sun Jan 25, 2009 11:31 pm ]
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I don't think it was mentioned here, but the ATX12v2.3 that the Modu82+ conforms to appears to have lowered the minimum current on the 12V1/2 rail to 0.1A and 0.5A. So maybe those fixes the problem?

Author:  hugocd [ Wed Sep 09, 2009 10:51 pm ]
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I met with a similar situation.
My setup is Silverstone Nightjar 45N + Asus P6TD Deluxe + OCZ 3*2G. This system did not boot up, and the fans spun once the power bottom was pressed, and then stopped immediately.
Then P6TD Deluxe was changed to P6T Deluxe V2, and a new Nightjar was used. This rig occasionally lit up, 1 or 2 out of 10.
When P6T Deluxe V2 is used with a Seasonic PSU, everything is OK.
Would anyone give some threads?

Author:  NeilBlanchard [ Thu Sep 10, 2009 2:05 am ]
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Hi,

Earlier in this thread may have the solution: add a little more load in the system to raise it's consumption enough to get it to boot. Then, once it is running, turn off the "extra" load once it is running.

Author:  Olle P [ Sat Sep 12, 2009 1:38 pm ]
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I find it difficult to believe this "problem" to exist in the first place...
A regular HDD draws >3A from the 12V line while spinning up. That consumption alone should be sufficient to overcome the minimum requirement.

Cheers
Olle

Author:  MikeC [ Sat Sep 12, 2009 1:49 pm ]
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hugocd wrote:
I met with a similar situation.
My setup is Silverstone Nightjar 45N + Asus P6TD Deluxe + OCZ 3*2G. This system did not boot up, and the fans spun once the power bottom was pressed, and then stopped immediately.
Then P6TD Deluxe was changed to P6T Deluxe V2, and a new Nightjar was used. This rig occasionally lit up, 1 or 2 out of 10.
When P6T Deluxe V2 is used with a Seasonic PSU, everything is OK.
Would anyone give some threads?

Definitely not a low power issue with an i7 rig. Some kind of incompatibility. Just go with the Seasonic.

Author:  hugocd [ Tue Sep 15, 2009 11:45 pm ]
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MikeC wrote:
hugocd wrote:
I met with a similar situation.
My setup is Silverstone Nightjar 45N + Asus P6TD Deluxe + OCZ 3*2G. This system did not boot up, and the fans spun once the power bottom was pressed, and then stopped immediately.
Then P6TD Deluxe was changed to P6T Deluxe V2, and a new Nightjar was used. This rig occasionally lit up, 1 or 2 out of 10.
When P6T Deluxe V2 is used with a Seasonic PSU, everything is OK.
Would anyone give some threads?

Definitely not a low power issue with an i7 rig. Some kind of incompatibility. Just go with the Seasonic.


Thank you.
A Seasonic M12D is sitting in the case now, and I can not hear it.

Author:  Jethro [ Sat Oct 24, 2009 10:32 pm ]
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Hi all!

I have a simple question about this problem. Does it mean that the PSU can't start at all or that the system can't boot?

I recently started to have problems with the following rig:

Fortron Zen 300W
Gigabyte 780G MBO
Athlon 64 X2 5000+
2x 1GB RAM
Sapphire HD4670 Ultimate
WD 6400 AAVS
DVD-RAM drive

It doesn't want to boot most of the time, lately. The system starts, but it doesn't get to the POST (no beeps at all). Hadn't had this problem before... I suspect it's some kind of MBO error, not the PSU. Any thoughts?

Thanks.

Author:  MikeC [ Sat Oct 24, 2009 11:04 pm ]
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Jethro wrote:
Hi all!

I have a simple question about this problem. Does it mean that the PSU can't start at all or that the system can't boot?

I recently started to have problems with the following rig:

Fortron Zen 300W
Gigabyte 780G MBO
Athlon 64 X2 5000+
2x 1GB RAM
Sapphire HD4670 Ultimate
WD 6400 AAVS
DVD-RAM drive

It doesn't want to boot most of the time, lately. The system starts, but it doesn't get to the POST (no beeps at all). Hadn't had this problem before... I suspect it's some kind of MBO error, not the PSU. Any thoughts?

Thanks.

Have you tried any other PSU? How old is the Zen? iirc, it was released 4~5 years ago. Capacitors do age over time, especially at high temps as you'd find in a fanless PSU -- they generally don't last as long as fan cooled ones. The PSU may not be able to power the components -- even though the overall demand is probably quite modest.

On the other hand, your mobo could have capacitor problems too -- but by the time the 780s appeared, I think the bad cap wave was over. You can tell visually if they're bad -- they bulge, leak... and in very bad cases, burst.

Author:  MikeC [ Sat Oct 24, 2009 11:12 pm ]
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Olle P wrote:
I find it difficult to believe this "problem" to exist in the first place...
A regular HDD draws >3A from the 12V line while spinning up. That consumption alone should be sufficient to overcome the minimum requirement.

Cheers
Olle

Oh, it was a real problem. It wasn't only the total startup current but also timing issues. iirc, the hdd (and other components even on the mobo) does not really start up until the mobo & psu have "shaken hands". Some mobos had delays in this process that made the PSU unstable, thus not giving a "Power-Good signal" -- which then caused the mobo to bail on the boot sequence.

Author:  Jethro [ Sun Oct 25, 2009 11:04 am ]
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MikeC wrote:
Have you tried any other PSU? How old is the Zen? iirc, it was released 4~5 years ago. Capacitors do age over time, especially at high temps as you'd find in a fanless PSU -- they generally don't last as long as fan cooled ones. The PSU may not be able to power the components -- even though the overall demand is probably quite modest.

On the other hand, your mobo could have capacitor problems too -- but by the time the 780s appeared, I think the bad cap wave was over. You can tell visually if they're bad -- they bulge, leak... and in very bad cases, burst.


Thanks for the response, Mike!
I tried with my old PSU (350W MSI 20pin PSU, but it worked). It successfully booted for 5 times in row. With the Zen, It's more like every 5th time, so I guess that's it... It's still under warranty, so I hope it'll be repaired or replaced.

Author:  Zero Cool [ Sat Nov 21, 2009 7:08 pm ]
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I had this problem with a Seasonic S12-500II (I think thats the model##) power supply and a Gigabyte P31 MB. I did some extensive testing and it was NOT related to too low of a load on the 12V side. I believe it was realted to a power up sequence issue.

When I first plugged the Seasonic in, it didn't work. nothing, dead. I was super bummed. To test the supply out of the computer IE all cables disconnected. you can use a jumper to short the green turn on wire from the 20/24 pin connector to any of the black wires (ground). If the supply is good. it should power up. In my case it did. So i tried it in a 2nd machine and the PSU/PC ran fine. Back into my HTPC and nada, dead. that's when i noticed the green light on my dell wireless KB puck was flashing a very quick short flash. I grabbed my meter and checked out the PSU +5VSB (stand by) line. with the supply on, but the PC off, this line should have +5V on it. this is what powers the standby/turn on circuits in a MB. with the GB MB and the Seasonic. this line would spike to 1-2V and then drop to zero. AHA! something about this line, the MB and the Supply was not happy. I contacted Seasonic and they weren't sure what the problem was but offered to replace the Supply No charge and sent me an RMA number.

Being the sort of person to not leave anything alone. I took a 6" 24P to 24P extension cable and cut the Purple VSB line and used a couple of push tab connectors to be able to disconnect and test this line.

the +5VSB should be able to supply 2-2.5amps according to the ATX supply guideline book. So i rigged up a test circuit and yup. i could draw 1-2amps no problem. ok so that works. I then measure the current draw from a known good PSU and the MB and it was around .25 amps. very low and well within the Seasonics capabilities. then I tried disconnecting the VSB line, turning the supply on and then a second later reconnect the VSB line and it FIRED UP! the machine ran great. and as long as you didn't disconnect the AC power you could start/stop the machine just fine. but disconnect the AC power and you had to do the Dis/connect the VSB line trick all over again....

I also tried loading the 12V line down all sorts of ways. car bulbs, lots of hardd rives, fans anything i could find and it made ZERO difference.

So I sent the supply back to Seasonic. they later sent back a different supply that works just fine.

Most power supply's have a Separate internal supplies for the 12V and 5V lines. the 3.3v is usually derived from the 5V supply. However in the Seasonic supply's. they have only one Internal 12V supply with a separate regulator to drop 12V down to 5V and 3.3V respectively. and this is very clean smart way to build an efficient supply. However when the supply first powers up. the 12V section needs to come online and then a few MS later the 5V and then 3.3V sections come online. to most MB's this is not a problem. But apparently Gigabyte boards are way more sensitive to the timing of these lines than most.

When the supply is first turned on. It seems to try and power up the MB for a split second maybe to test the lines and shut down if there is a problem and i think the timing of the supplies or some other issue related to this causes the supply to immediately shut down hence dead supply.

If i had kept the faulty supply longer. I would have done some more testing with a logic analyzer at start up to see the timing sequence and just how much delay there is between switch flip and +12, +5 and +3.3V lines.


Zc

Author:  MikeC [ Sat Nov 21, 2009 8:12 pm ]
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Zero Cool -- good post, ;) You got to the heart of one of the timing issues. There was more than one.

Author:  Zero Cool [ Thu Nov 26, 2009 8:47 am ]
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MikeC wrote:
Zero Cool -- good post, ;) You got to the heart of one of the timing issues. There was more than one.



Thanks, the new supply runs great but i was able to acquire an open box nexus Value 430 that while not as pretty. is doing the job just fine and is in fact a degree quieter then the Seasonic!! simply amazing!

BTW. Seasonics customer support was great! they responded right away even late at night with multiple emails. sent me a no questions asked RMA number and a replaced my supply no charge. not even return shipping or anything!

Author:  65dolltyson [ Sat Aug 06, 2011 2:05 am ]
Post subject:  Re: Low power system not booting with high efficiency PSU?!

Thanks for the info! This makes me worried, of course. I'm currently looking at an Epox board with the same chipset as the one from Asus mentioned above. :twisted:

Author:  Owen [ Wed Feb 22, 2012 5:27 pm ]
Post subject:  Re: Low power system not booting with high efficiency PSU?!

I'm not sure if this is the problem with my Seasonic X-650 or the PSU is simply dying.

I've had the X-650 for about 2 years and during the past few months I started to get delayed response to power on, until yesterday PC simply would not turn on. Motherboard's power on button LED is on though, but it also could not power on the PC. I unplugged and replugged, which seemed to fix it. But today I got it again. So it's unpredictable.

My system has 2 SSDs, 1 WD Green, ATI 5450, so low power indeed, the CPU is a quad-core i5, which I'd think should draw enough power?

Author:  MikeC [ Wed Feb 22, 2012 11:49 pm ]
Post subject:  Re: Low power system not booting with high efficiency PSU?!

Owen wrote:
I'm not sure if this is the problem with my Seasonic X-650 or the PSU is simply dying....

If it was happening from day one, then too low power draw could have been an issue, but after 2 years with the same components? Sounds like RMA time for the PSU -- tho I'd double check it is not something else by trying another PSU (assuming you have one around).

Author:  Owen [ Thu Feb 23, 2012 2:36 pm ]
Post subject:  Re: Low power system not booting with high efficiency PSU?!

Well the components are not exactly the same, I've gone from Velociraptor to SSD, so load has reduced a little bit. :D

I'm waiting for an X-400 to arrive before I start the RMA process. Good to have a back up PSU anyway.

Author:  wandal [ Sat Nov 23, 2013 4:26 pm ]
Post subject:  Re: Low power system not booting with high efficiency PSU?!

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