HX520W fails to start if AC interrupted

[agspoon]

I have just put together a new build using a HX520W, and I'm having trouble getting the system to power up after the AC supply has been removed from the system. P5K Deluxe/WiFi, E8650, 2GB Corsair 8500C5D, WD Raptor, Plextor PX-810SA.

 

From a complete cold start (PS switch off), turn on PS, green LED on Mainboard is lit, hit power button, all fans spin up 1 second, all fans spin down 2 sec, all fans spin up again 1 sec, all fans spin down. At this point, hitting the power button will not get any response. If I turn off the PS for a few seconds, and back on again, it will reset and hitting the power button will start the same cycle all over again.

 

The only way to get the machine to power up is to unplug the disk drive or graphics card from the PS and then hit the power button. Once the machine has powered on once, I can power it down (with the power button, AC still on) connect up the disconnected device, and all is well. It has never failed to power up with the power button after I go through this little dance.

 

However, should the AC be interrupted or I power off the PS with its switch, I have to open up the case and go through the whole process again.

 

From what I've read, I think the first application/de-application of power is normal for the P5K. It is the failure of the PS on the second attempt that is not right. It seems like the PS is being over loaded on the second attempt by the Mainboard to power up. The fact that I have to power off the PS for a few seconds in order to reset it, leads me to believe some sort of soft fuse is tripping.

 

I'm fairly certain that my setup does not exceed the runtime capacity of this 520W PS. Am I exceeding the PS's instantaneous capability? If so, then why does it work after establishing the first power up after returning AC?

 

Any ideas?

[agspoon]

I have just put together a new build using a HX520W, and I'm having trouble getting the system to power up after the AC supply has been removed from the system. P5K Deluxe/WiFi, E8650, 2GB Corsair 8500C5D, WD Raptor, Plextor PX-810SA.

 

From a complete cold start (PS switch off), turn on PS, green LED on Mainboard is lit, hit power button, all fans spin up 1 second, all fans spin down 2 sec, all fans spin up again 1 sec, all fans spin down. At this point, hitting the power button will not get any response. If I turn off the PS for a few seconds, and back on again, it will reset and hitting the power button will start the same cycle all over again.

 

The only way to get the machine to power up is to unplug the disk drive or graphics card from the PS and then hit the power button. Once the machine has powered on once, I can power it down (with the power button, AC still on) connect up the disconnected device, and all is well. It has never failed to power up with the power button after I go through this little dance.

 

However, should the AC be interrupted or I power off the PS with its switch, I have to open up the case and go through the whole process again.

 

From what I've read, I think the first application/de-application of power is normal for the P5K. It is the failure of the PS on the second attempt that is not right. It seems like the PS is being over loaded on the second attempt by the Mainboard to power up. The fact that I have to power off the PS for a few seconds in order to reset it, leads me to believe some sort of soft fuse is tripping.

 

I'm fairly certain that my setup does not exceed the runtime capacity of this 520W PS. Am I exceeding the PS's instantaneous capability? If so, then why does it work after establishing the first power up after returning AC?

 

Any ideas?

[RAM GUY]

There are 2 possibilities. One is that the PSU is tripping the "Over Current Protection" or "Over Voltage Protection" due to an out of spec signal on the cold boot, but during a warm boot the component is fully charged and not going out of spec. The second possibility is that there may be a bad component in the PSU, if this is the case, we would want to have it sent in to us so we can find out what the issue is.

 

Before having the PSU replaced, if possible, you may want to test it in a known working system. If it gives you the same issues, we would definitely want to have it replaced, however if there are no problems in another system, you may want to RMA the board.

 

If you decide you would like to RMA the PSU please let me know, so that we can set up a failure analysis RMA to determine what the issue is.

[agspoon]

An update. I dug in a little more to see if I could find out what was sucking so much power on power-up. I must have been on the border line, as even disconnecting the SATA DVD drive would allow the system to power-up (albeit with the "double bounce" behavior).

 

I thought maybe I had a bad cable, so I systematically replaced each one. When I got to the graphics card cable (supplementary 6 pin PCIe) I decided to try the one that came with the card rather than the one from the PS. I had been using one of the Corsair supplied PCIe cables from the PS to the card. I replaced it with a cable combination that included a PCIe to dual 4pin Molex adapter connected to one of the Corsair dual 4pin female Molex cables. Kind of ugly but it did the trick.

 

With this change, the system powers up every time from a cold start and as a bonus it no longer has the "double bounce" behavior. Apply power from any prior state, and everything comes up first time. :):

 

I wish I knew why, as the Corsair PCIe-to-PCIe cable is a more clean solution. I did notice that the Corsair cable has all 6 pins of the connector populated, whereas the PCIe end of the card adapter cable only had 5 of the pins populated. One site that has a pinout of the PCIe connector shows that one of the center pins is supposed to be empty (3-GND, 2-12V). Could this be related to the issue? Could the graphics card have been inadvertently sinking power via the extra 12V pin in the cable?

 

Anyway, I don't know why it works, but the good thing is that it does. Thanks for the reply. I'm very happy with the quite operation of the PS and high level of workmanship.