External Device Blew USB Bus??

[LadyFaire]

Plugged in a Bluetooth keyboard to charge up, since it didn't come with an AC adapter. I think the flippin' thing blew my USB bus, since my ports no longer work. I KNOW it blew my USB 3.0 hub, because it no longer works at ALL.

I thought you couldn't blow the bus with an external device??

[SteveNielsen]

Re: External Device Blew USB Bus??

Hot-swappable does not mean indestructable.

[LadyFaire]

Re: External Device Blew USB Bus??

The company that sold the Bluetooth keyboard claim that it is not possible for it to have blown the bus. All I know is that I plugged it into the hub first - it just needed charging. The hub started flashing and then just died. Stupid me, I plugged it into a direct USB port. Nothing. The hub, the port the hub was plugged into and the second port no longer work at all.

Any ideas or suggestions??? I cannot afford a new laptop at this time.

[budm]

Re: External Device Blew USB Bus??

It may have blown the protection fuse on the 5V line for the USB circuit. Do you still get 5VDC on the USB pin 1?

[LadyFaire]

Re: External Device Blew USB Bus??

I will have to check that. To be perfectly frank, I cannot figure how to check the voltage on a USB port! I've tried all sorts of ways, but don't get any coherent readings. Clue me in - how do you set the probes for a USB port??

[SteveNielsen]

Re: External Device Blew USB Bus??



Set meter to low voltage DC scale, put red probe on pin1 and black probe on pin4.

[budm]

Re: External Device Blew USB Bus??

Make sure to use very small probes so you will not accidentally short pin 1 to the metal shroud which is ground and shorted out the 5V line.

[SteveNielsen]

Re: External Device Blew USB Bus??

Very good point Bud. As usual.

[LadyFaire]

Re: External Device Blew USB Bus??

The probes I have are too thick. Having hubby bring home some smaller ones, and I'll try it then. Appreciate the help!!

[pravin6p]

Re: External Device Blew USB Bus??

you can solder a staple pin on the probes . it ll work.

[goontron]

Re: External Device Blew USB Bus??

you can solder a staple pin on the probes . it ll work.

that's a little how ya 'doin

[khaahk]

Re: External Device Blew USB Bus??

I suggest you take that keyboard to the company that sold it, find the most expensive laptop there and ask them to plug it in...

[eccerr0r]

Re: External Device Blew USB Bus??

I've seen a lot of host USB ports, especially cheap ones, have unfused outputs and could cause damage if a shorted USB device is plugged in.

Another trick you might want to try to measure voltage of a USB connector:

Take a piece of paper and cut it to the width of the USB slot. Draw four, very dark lines with a graphite #1 pencil that line up with the pins on the USB bus. Extend them, and use these graphite tracks to measure the voltage of your port with a high impedance multimeter.

The graphite is probably resistive enough to not cause problems if they short (but watch out for flammable paper!) and should make it easy to "plug" into the port.

[ktmmotocross]

Re: External Device Blew USB Bus??

bad battery

when its decharged its nearly shorted, so there is high current to charging and blow the fuse.