Gp2x Squeals

[slygamer]

I had left my GP2X off, but still plugged in to the power adaptor (powered on) and USB connected to the PC (also off). It had been like this from midnight through till 6:30pm, so about 18 and a half hours. After this time, the GP2X was squealing softly, like a mosquito, even though it was turned off. I unplugged the power adaptor, it still squealed. I powered it on under battery power (still the original batteries, over one year old now), turned it off, still squealed. I took the batteries out, it still squealed. Unplugged the USB cable, squeal stopped. Remember, the PC is off. Well, as off as the soft-off motherboards get these days. Plugged the USB back in and the squealing started again.

So, something about having the GP2X connected to a powered USB cable for an extended length of time causes the speakers to softly squeal. Odd. It's quiet now though.

 

[Vimacs]

strange, especially since the usb powerlines are not connected, probably tons of interference on your usb port, or maybe a broken usb cable?

 

[linoleum13]

Are USB cables still powered even when the computer is turned off (soft off as the OP says)? I could imagine that could cause some interference on the GP2X's circuits.

My dell workstation at work has a similar problem. The integrated soundcard picks up a lot of interference from the rest of the motherboard and I can hear it in my headphones. No integrated audio for my personal machines!

 

[gaterooze]

Demonic possession, mate.

 

[thumpgun]

i think the usb lead is acting like an ariel and picking up radio signals from passing ufo's..... :blink:

 

[slygamer]

Are USB cables still powered even when the computer is turned off (soft off as the OP says)? I could imagine that could cause some interference on the GP2X's circuits.

Some are. I've noticed several machines here at work that have the keyboard and mouse lights still shining brightly even when the PC is turned off.

 

[Epicenter]

If it's very high pitched, it's probably some component in the GP2X's PSU hardware (internal). Capacitors can whine, and so can inductor and transformer coils as they vibrate extremely rapidly. If you put your ear near a PC's CPU socket with the fans turned off you can usually hear a faint whine from the CPU power regulation circuit.

 

[Dimacus]

In the bios you can set the computer to "wake up" on the touch of ceartain keys.
This, in combination with some other bios settings (usb keyboard support is one example) can cause the computer to always power some or all usb ports.

That was atleast the case in my sisters computer which had the num,scroll and caps leds lighted when the computer was of.
I suppose that the ps2 ports is somwhat related to the usb ports, since you can connect a usb mouse with just a simple adaptor to the ps2 port.

 

[Epicenter]

In the bios you can set the computer to "wake up" on the touch of ceartain keys.
This, in combination with some other bios settings (usb keyboard support is one example) can cause the computer to always power some or all usb ports.

That was atleast the case in my sisters computer which had the num,scroll and caps leds lighted when the computer was of.

Yes, this is standard in PC-style PSUs. The +5VSB (5 Volt Stand By) rail is always active as long as sufficient AC power is applied to the primary. +12v, +5V, +3.3V and the rest are only activated when POWER_ON is grounded on the 20 (or 24)-pin power connector that goes to the motherboard (triggered by the power switch).