I have a couple USB hard drives with a Y cable. One plug is data and the other plug supplies power to the hard drive.
At least three times now, I’ve plugged this drive into the USB ports and the power supply stops!! :eek: If I unplug the cable, the power comes back and the pc reboots. Giving me a nasty boot message from Windows (Windoz hates having power disrupted :p). I’m pretty sure it’s the power leg of the Y doing this. But, I’m not certain.
It seems like the problem occurs if I use different rows on USB.
I have 4 ports in the first Row. Then 2 in the second row plus 1 RJ45 CAT 5 jack. I always have a Cat 5 cable plugged in. So, I know I’m not accidentally plugging USB into that.
like this (numbering is how the motherboard manual lists them)
|.2.|…|.3.|…|.4.|…|.5.|
|.1.|…|.0.|…RJ45
Just now I had the external drive in 3 and 1. Jack 2 is very, very hard to plug in. The metal plate seems to block it a little. Soon as I plugged that cable in 1 the power supply died. Jerked it out, and the pc comes back to life and reboots.
Right now, I have the external drive in 2,3 and everything is cool.
Why would plugging into 3, 1 or 3, 0 short this thing out?
USB supplies 5v to devices. One of your cables or devices has a power to ground short. There are supposed to be self-resetting fuses in the USB circuity to guard against this sort of problem (it’s actually part of the USB spec), but your PC must have cheaped out on the protection. Figure out what it shorting, and fix it throw it away.
I have this old Dell that used to be my graphics workstation and now I just use as a file server. No monitor connected to it or anything; whatever I need from it I just do over my home network. For the most part, it just stores years-old projects and email in case I ever need them.
But a couple of months ago I plugged a USB thumb drive into it, probably the first time the USB port has been used in three years or so. The ports are on the back where they’re hard to see so after a quick glance to locate them in general I inserted the drive by feel.
POP! Big spark, machine switches off immediately and the thumb drive never works again. Upon examination, I see that the little white piece that separates the two different USB ports on the machine is missing, so probably I managed to contact both ports at one time with the plug of my thumb drive, closing a connection between them… which, the point is, may be essentially what’s happening to you if your cable is shorted.
Minor nit that may or may not help understand the issue - both plugs are very likely providing power. USB devices only get 500mA from their host. Power hungry devices deal with this by having two connections, giving a maximum of 1000mA (also know as 1A)
Does the problem always occur when one of the particular cables in plugged in? Or is it when the second one is connected, regardless of order?
I agree with **beowulff **that you may have a short to ground. A multi-meter with fine enough probes may help you here.
Yes, I just tried port 1 (bottom row) with my mp3 player (it’s seen as a flash drive on my pc). I still had the hard drive in 2,3 on the top row. Everything works.
Looking at the mb manual, top row of ports is in it’s own shielded box. The other row of ports is in a different shielded box. I wonder if this is two totally separate usb hubs internally? Maybe hooking the same device to two hubs (Y cable) is causing a short?
Yes, you’re supposed to put the two parts of the Y into different USB hubs. I believe your OP is slightly incorrect: both parts of the Y normally supply power. Your HDD requires more power than one hub will provide.
