New Power Supply problems

[amlord]

I recently bought a new graphics card to Crossfire with my Radeon 7870. I bought a second card of exactly the same MSI card that I have.

My old power supply was: http://www.newegg.com/Product/Product.aspx?Item=N82E16817341017&Tpk=ocx%20600w, 600W OCZ model. The problem was that these cards each need 2 VGA cords and that power supply only has two, not four.

So I bought a new power supply, this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817438007 EVGA 750W power supply.

Here's where I start having problems:

So I install the new PSU and when I switch the power supply on switch, the fans "twitch". THey get power momentarily. The system won't boot, however.

I put my old PS back in and everything works fine.

So I try replacing components one by one and the system boots to BIOS if the hard drives are not connected. However, I get that message there is no boot disk.

When I connect the DVD drive and HDDs (I have two) to the PSU with the SATA cable, the power supply won't even start up when I hit the ON button.

What is going on?

 

[InvalidError]

I would guess your new PSU either overshoots during startup and trips overvoltage lock-out or fails to ramp output voltages before the bootstrap timer times out and trips the under-voltage lock-out. Without an oscilloscope hooked up to PSU rails to monitor exactly what happens when the shutdown occurs, it is very difficult to tell.

 

[C12Friedman]

In English, what InvalidError is trying to say is, "your PSU is not working properly and you should RMA it" but in his defense, you did ask "what is going on" so he told you.

 

[amlord]

Is the problem with the SATA section of the PSU do you think? Is there anything I can do to check if it will work?

Thanks for the help.

 

[InvalidError]

In English, what InvalidError is trying to say is, "your PSU is not working properly and you should RMA it" but in his defense, you did ask "what is going on" so he told you.

Well, what I described can happen even when the PSU is working properly... either due to excessive loading on components or excessively large current swing during the boot process.

Since OP said his PC boots fine without HDDs attached, I would guess he's running into under-voltage during boot. Configuring staggered spin-up in the BIOS might help with that.

It is a little odd that a 750W PSU would have a harder time with this than a 600W PSU on a given system so a swap-out to see if this is a problem with the specific specimen or the model itself would make sense.

 

[InvalidError]

Is the problem with the SATA section of the PSU do you think? Is there anything I can do to check if it will work?

Thanks for the help.

There is no "SATA section" in the PSU. The PSU provides bulk-regulated 12V, 5V and 3.3V rails. Cables draw from whichever rails are appropriate for the connectors attached to them.

As for things you can try, see if your BIOS has an option for staggered spin-up. This should reduce the power draw during boot a little and might be enough to let you boot the OS and see if your system behaves properly beyond that.

 

[ko888]

I would use a multimeter to determine if the voltages on the SATA connector are on the correct pins. You never know if the PSU was mis-wired at the factory. If it was mis-wired it can cause a short-circuit when connected up to a SATA device that would trigger the short-circuit protection circuit causing the power supply not to latch ON.

 

[C12Friedman]

I would use a multimeter to determine if the voltages on the SATA connector are on the correct pins. You never know if the PSU was mis-wired at the factory. If it was mis-wired it can cause a short-circuit when connected up to a SATA device that would trigger the short-circuit protection circuit causing the power supply not to latch ON.

I would think that would be a good enough reason for an RMA but thinking along the 'possible short' lines, I'll suggest visually checking the fingers of the optical and hard drive SATA connectors to ensure nothing is amiss there - what happens if you hook up the OS hard drive only? What happens if you hook up the optical drive only?
Just to confirm here... on the PSU side, the cable is connected to one of the headers labeled SATA (one of the three at the bottom if the lettering is properly oriented) since it appears to easily go into the peripheral header too

 

[amlord]

I would use a multimeter to determine if the voltages on the SATA connector are on the correct pins. You never know if the PSU was mis-wired at the factory. If it was mis-wired it can cause a short-circuit when connected up to a SATA device that would trigger the short-circuit protection circuit causing the power supply not to latch ON.

I would think that would be a good enough reason for an RMA but thinking along the 'possible short' lines, I'll suggest visually checking the fingers of the optical and hard drive SATA connectors to ensure nothing is amiss there - what happens if you hook up the OS hard drive only? What happens if you hook up the optical drive only?
Just to confirm here... on the PSU side, the cable is connected to one of the headers labeled SATA (one of the three at the bottom if the lettering is properly oriented) since it appears to easily go into the peripheral header too

Yes you are correct.

I hooked up my old PSU and everything works normally. I'm going to RMA the EVGA power supply.

Thanks all.