Problems with USB devices

[liquidxtal]

Please can someone help with the following problem?

My computer (Windows XP) has two USB inputs on the front and two on the back. When I insert a memory stick in either of the front sockets it registers as drive (G:) in “my computer” and functions ok i.e. I can transfer data between my hard drive and memory stick.

When I remove the memory stick and then connect my external hard drive to either of the rear sockets it registers as drive (F:) in “my computer” and functions ok i.e. I can transfer data between my hard drive and external hard drive.

The problem arises when I connect my hard drive and memory stick simultaneously, everything then goes to pot, I am unable to transfer data between any of the drives and the following message is displayed:

Cannot create or replace File ABC etc:

Cannot find the specific file.

Make sure you specify the correct path and the file name.

I really need the ability to transfer data from my memory stick to my external hard drive.

My knowledge of computers is somewhat limited and I am getting on in years so any help patiently offered would be most appreciated.

Thank you

Barry

[KenB]

Hi and welcome to ExTS

 

I suspect that this may be a power issue.

 

Can you transfer data between 2 Memory Sticks?

 

How is your external drive powered?

Do you use the USB port for this or a mains adapter ?

[liquidxtal]

Hi KenB and thanks for the fast response.

I repeated the scenario with two identical memory sticks and met with the same result and error message.

The external hard drive has its own mains power supply.

I appreciate your help.

Barry.

[KenB]

two identical memory sticks and met with the same result

It could still be a power issue.

 

Plug in the memory sticks.

Start > Run ....type in .....devmgmt.msc ........ENTER

Click the + to expand the USB Controllers

 

Right Click on USB Root Hub in turn > Properties > Power

It will say here what power is required

 

The USB port can only supply 500mA

 

This does not mean to say that the port is supplying the correct current.

[liquidxtal]

Thanks again KenB

 

I carried out the procedure as suggested, thanks for the clear instructions.

The first 3 labelled USB Root Hub read as follows:

 

Hub Information

Total power available 500mA per port

Attached devices

Description Power Required

2 Port(s) available 0mA

 

The last laballed "USB Root Hub" read as follows

The Hub is self powered

Total power avaiable 500mA per port

Attached devices

Description Power required

USB Mass Storage device 200mA

USB Mass Storage device 200mA

4 Ports Avaiable 0mA

[KenB]

This does not necessarily indicate that the USB ports are OK - it is just an indication of the required power for the Memory Sticks.

The Total Power available has not been measured.

 

Without putting an ammeter on the ports it is difficult to say if the output is actually enough to power more than one device.

Theoretically there should be 500mA available on each - but if there is a motherboard or PSU problem causing the ports to behave as they are this is difficult to diagnose.

 

Try this "Fix"

http://windows.microsoft.com/en-us/windows-vista/Tips-for-solving-problems-with-USB-devices

 

This will only fix the problem if it is software related.

[liquidxtal]

Thank KenB,

I tried your suggestion but received the following message:

Microsoft Fix It

The trouble shooter does not apply to your system.

We’re sorry, but this trouble shooter is not compatible with your current system configuration

I noticed the site mostly catered for Vista problems. I did try to find an equivalent site for XP without success.

I am tempted to cut up an old cable to act as a breakout box and fix a variable load across the +5v line and earth to see if I can pull 500mA, if so I will let you know the result.

Thank you

Barry

[KenB]

Hi Barry

 

Sorry about the FixIt - forgot you were using XP.

 

You only seemed to have problems when you had 2 devices connected.

 

When you adapt your cable do you get a drop in current if you have another device connected ?

 

===========

 

Another option is to use a PCI USB card - they only cost a few ££

(assuming desktop)

[liquidxtal]

Hi KenB,

 

To pull 200mA I need a load of approx 25ohms, unfortunately I have been looking without success for such, however I will visit the town this weekend. The PCI USB card sounds promising, although I have a tower which is tucked right under my work top, but at the end of the day I might have no choice. I have never heard of these cards until you mentioned them! In the late sixties, I had many unpleasant experiences with computers especially when using the language Fortran which we used in conjunction with punch cards during chemical analysis using X-ray crystalography, what a nightmare, it put me off computers for many decades after!!

Will get back to you

Thank you

[KenB]

I agree with your calculation - 25 Ohms to draw 200mA on a 5v supply :)

A 50 Ohm potentiometer may give you a bit of flexibility.

It would need to be capable of 2 - 3 Watts if you are testing the port to full capacity.

 

Fortran, if my memory serves me correctly, was predominantly a scientific language was it not ?

[liquidxtal]

Hi KenB,

Your ease of use of the terminology suggests that you are electronics trained!

Fortran might have been a scientific language for some, but to me it was a nightmare language,

very, very rigid and unforgiving.

Because of this problem complexity and my inexperience I’ve decided to go for the PCI USB card you mentioned earlier, however out of curiosity and interest I will still measure the current drain both on a single USB stick and a pair, also noting any voltage drop.

Will keep you informed.

Thanks

Barry

[KenB]

Your ease of use of the terminology suggests that you are electronics trained!

I taught electronics for more years than I care to remember - retired now :)

 

The PCI card is independent of the 5v supply that the USB ports use so you should not have the same issues.