Very strange USB channel behaviour, replace motheboard?

[Tatsh]

I have a laptop, an HP Pavilion dv5030us (dv5000 series). The left-side USB channel, which has two ports, seems to be entirely dead, except if I plug in a powered USB hub. If I plug in a powered USB hub into either of the ports, then the other port becomes alive as well. On the right side there is only one port where I normally plug in my hub, so I am not surprised it is working (for a long time it has been not providing its own power to devices, thought it was just normal for that port). Now this problem has extended to the left side ports, and I am not sure if my only option (if I want this truly fixed) is to replace the entire motherboard. If not, I'm wondering if there is any soldering work I can get done that would fix the problem.

Thanks in advance

[CWR03]

It sounds like something is broken in the port, and plugging in the hub is jumpering around it. Sounds like something that could be fixed with careful soldering or an epoxy solder paste, but finding it may be difficult.

[fly_away]

I would try looking into the bios, maybe some settings of "always on" or something like that are disabled

[Tatsh]

Unfortunately (thanks HP), they have almost no device options in the BIOS, and none for USB. I'm hoping it can be like the latter post by CWR03. I am having a guy I know who can do soldering (and fixes laptops all the time) look at it today or tomorrow.

[Tatsh]

I talked to someone and my only solution (without looking at the board and without replacing the motherboard) is this:

Use a thin-gauge wire (breadboard-style wires) to take power from any chip that draws +5 v or more, use a transistor in between to control the voltage and then send that to the USB circuit. That should turn them on again. This is very risky and I risk destroying the board (while doing this installation or in the future). So instead I am going to just sell it as it is.

The cause of this: I was using a IDE->USB adaptor that uses a molex connector for outside power. I reversed the molex connector (cheap rubber kind, easy to reverse), and the laptop shut off. For some reason that night the USB ports still worked after powering the laptop back on; next day, dead.

[dat720]

Sound's like you damaged the usb internal "hub" (it could be part of the southbridge or it could be a seperate usb controller) and it has completly died slowly, once you have done damage like this to a motherboard there is pretty much no saving it, you could get a pcmcia to usb adapter, or as you said already sell it :)

Don't even bother with a replacement motherboard for a laptop, the time effort and cost involved (and danger factor as LCD's and Motherboard's are very sensitive and easy to damage) with replacing it is usually outweighed by replacing the laptop altogether (atleast with australian prices)

[*.mp4 guy]

I disagree, I would guess that you damaged some of the capacitors that supply the 5v power to the USB hub when you reversed the molex connector, some of them remained operational, but they were killed by the extra stress of running the USB hub without the broken capacitors. This would explain all of the behavior, as the circuits would still be functional, depending upon the layout of the motherboard it may be reasonably easy to replace the capacitors, or nearly impossible.

[dat720]

As a qualified electrical engineer i can safely say that it is not the caps causing the problem, capacitor's pretty much are used for 2 things, storage, and smoothing the ripple in the supply rail, in this case they would be used for smoothing, ie preventing the voltage from rapidly changing up and down as switching regulators tend to do, if you really want to check you could put a multimeter across the outside pins to see if there is 5v on them with the pins facing down the very left pin should be +5v and the very right should be ground, if there is around 5v then the usb controller is most likely damaged, if the voltage is varying above or below by more than about half a volt then the regulator is damaged.....

[*.mp4 guy]

Well, A problem with the 5v power subsytem that feeds the usb ports is the only logical explanation I can think of for the behavior being described. If it was a problem with the controller chip(s), connecting a powerd usb hub wouldn't do anything. It doesn't matter how much power you give a fried chip, its going to be useless no matter what.

[dat720]

Didn't i already offer an explanation for that?

if there is around 5v then the usb controller is most likely damaged, if the voltage is varying above or below by more than about half a volt then the regulator is damaged.....