USB ports not getting enough power.

[MidnightDistort]

http://support.hp.com/us-en/product/Compaq-Presario-SR5000-Desktop-PC-series/3823953/model/3875749/document/c01237548/

Link is the motherboard specs, anyway since i have had trouble connecting an external hard drive to this computer, tried everything on the software side and i have determined that the USBs are not getting enough power.

Could this be remedied by putting in a new PSU? I have heard that it may not be the cause but i took a look at the PSU and there are some bulging capacitors telling me that the PSU is on it's way out and i think is the reason for the USB ports not working right with my external drives.

 

[jimmysmitty]

Is this a 2.5" external drive or a 3.5" external drive?

 

[MidnightDistort]

3.5 external drive. It has been tested on other computers and it works fine.

 

[jimmysmitty]

Then it should not be getting any power from the USB and power only from the wall adapter so it is not a power issue. 2.5" drives run on the 5V line while 3.5" drives run on the 12V line.

It could be a compatibility issue or even a driver issue. Have you checked your USB drivers on the PC that is having the issue?

 

[sizzling]

Its possible the PSU could be the cause but I would think its more likely motherboard due to its age. Older motherboards used to gave a lower maximum current, often only 0.5A

 

[MidnightDistort]

Yep, i have uninstalled and reinstalled my usb drivers so i don't think it's that.

i have heard that often the motherboard is at fault though is not that old, if it's the motherboard though then it would be more ideal for me to get a new computer and my laptop isn't worth upgrading either so i figured it could be the first signs that my PSU is going bad (besides the bulging capacitors).

 

[Traciatim]

If it's a 3.5" drive then you generally need an external power source, since USB with data isn't designed for higher power devices. If the data lines are used then generally you get 0.5A at 5V which is 2.5 watts (for USB2 and before). Some drives will also have a secondary USB port that you need to plug in that acts like a charging cable for things that support high current (up to 2.1A, or basically 10 watts), but that's unlikely from an older motherboard but you could use a USB charger for that secondary cable if that's how it works.

 

[jimmysmitty]

If it's a 3.5" drive then you generally need an external power source, since USB with data isn't designed for higher power devices. If the data lines are used then generally you get 0.5A at 5V which is 2.5 watts (for USB2 and before). Some drives will also have a secondary USB port that you need to plug in that acts like a charging cable for things that support high current (up to 2.1A, or basically 10 watts), but that's unlikely from an older motherboard but you could use a USB charger for that secondary cable if that's how it works.

I have yet to see a USB powered 3.5" drive. Mainly because USB, even the faster charging ports, does not provide enough power as it only has 5V and can only push, at current, up to 1.5A through it. 2.5" drives run off the 5v rail and need way less power, on average 7W is what they need to run at max throughput and USB can provide that.

If it is working with other systems then it is something specifically with the system that is having the issues.

When you plug it in do you see anything come up in the device manager?

 

[MidnightDistort]

The connection is random. Sometimes it will disconnect and reconnect, won't connect at all or will connect at 1.1 usb speeds. It leads me to believe that the USB ports are not getting the 0.5A.

 

[jimmysmitty]

The power has nothing to do with the speed. On a USB port there are 4 pins. There is the D+ and D- (the data lines) and the +5v and the ground. It could be a problem with the ports or the board could be failing.

The best way to test is with a USB flash or 2.5" USB HDD as they both pull the needed power from the USB port itself while a 3.5" does not.

 

[Traciatim]

The connection is random. Sometimes it will disconnect and reconnect, won't connect at all or will connect at 1.1 usb speeds. It leads me to believe that the USB ports are not getting the 0.5A.

The point is USB is 0,5A at 5V which is 2.5 watts. The drive will not work with only that much power. It should have a place to plug a power adapter or some other way of getting enough power.

 

[MidnightDistort]

Well im not talking about the drive getting power. That is no problem, the problem is being able to connect the drive to the PC which does not have a stable USB connection. Doesn't the USB need stable power so it can transmit the info or does it not work that way?

 

[jimmysmitty]

Well im not talking about the drive getting power. That is no problem, the problem is being able to connect the drive to the PC which does not have a stable USB connection. Doesn't the USB need stable power so it can transmit the info or does it not work that way?

As I said the only way to be sure is to test another USB device similar to the HDD to determine if it is the USB ports on the system.

While USB does use some power the .5a you are talking about is on the +5v line which is used to power smaller devices. The larger HDD has its own power so all it needs is the data connection.

If it was the USB ports going bad or low on power though, your mouse and keyboard would also not work as they pull their power from the USB port as is needed, such as any LED lights on it.