Motherboard still drawing power after shutdown.

[crazyg0053]

Hey guys, got a problem thats been baffling me for a while now.

Maybe 1/20 times when I shutdown my system, the machine will power down but my BlackWidow keyboard will stay fully illuminated and my speakers will start humming as the stereo connections pick up current (The amp is permanently cranked up to 100% so the speakers will make similar noise if you touch the plugs with your fingers when the sound system is turned on).

The system will stay in this state until I physically unplug the PSU from the wall and wait ~30 seconds for the capacitors to drain. Ive shut it down at night and come back to the pc in the morning with it still doing this.

Problem occurs on both my current PSU and my old Corsair HX850. The problem occurs regardless of OC

Seems to me theres a problem with the mobo but I may just be trying to rationalize buying an 1150. Thoughts?

Motherboard: Asus P6X58D-E
CPU: Intel Core i7 930 @ 3.99Ghz|1.3V
CPU Cooler: Noctua NH-D14
Case: CoolerMaster HAF 932
Memory: 3x 2GB Corsair Dominator @ 1600 mhz 8-8-8-24
PSU: PC Power and Cooling Silencer Mk3 1200 Watt
GPU: 2x EVGA GTX 470
SSD: Samsung 840 Pro 256GB
HDD1: WD Caviar Black 2TB 7200 RPM 64MB
HDD2: Seagate 1TB 7200 RPM 32MB
OS: Windows 7 Ultimate 64Bit

 

[groundrat]

AC in wires can produce an RF field that can induce a current on unshielded speaker wires and cause what you are describing.. If you can solder you can replace the unshielded wires with shielded wires and solve the problem that way.

What do the power settings in the OS look like? Is your computer sleeping or is it really off?

Capacitors and inductors can take a while to fully discharge, and that could be part of it, but not multiple hours with a large enough field to induce on your speaker wires. You’ve got a big power supply, but not that big.

With the amp maxed out any kind of electrical field could cause the feedback your getting. Having the amp maxed like that will eventually degrade the components and cause… Interesting things to happen. I’d turn down the amp to 50% volume and turn the amp off when you turn off your computer. Should do the trick.

If 50% is too little sound, you need a more powerful amp.

 

[crazyg0053]

The problem isn't so much the speakers making noise, that is one of the symptoms of the motherboard pulling power.

I doubt the OS is the problem, and it is shutting down not going into sleep or hibernation.

This doesn't happen every time. As I said previous its maybe 1 time in 20. When the system shuts off normally, the keyboard lights go off and the speakers don't hum because the current has been cut off. Problem is why seemingly at random, the mobo continues to draw power, supply USB devices with power etc after the system shuts down.

As for the speaker system I have an old Altec Lansing ADA995 I bought back in 2003 that I have wanted to replace for years but it refuses to die. In all of Altec Lansing's brilliance the amp is PERMANENTLY set to 100% and cannot be changed. Sound quality is fantastic but I cant turn my computer past around 10% without making my ears bleed. (I have had multiple rude surprises when reinstalling windows with the sound defaulting to 50%).

 

[groundrat]

Sorry I misunderstood. I don’t have any idea why it would do that. Especially intermittently.