unrecognized USB device

[Dianne Sagun]

I’ve was trying to plug a USB on one of my USB ports on my CPU but I was given an error that the USB Device is not recognized. What seems to be the problem, I was just using that port previously? How can I fix it?

[Pete Kaine]

Is this a front port on the pc? Have you tried it in one of them round the back?

[Martin Walker]

Welcome to the SOS Forums Dianne!

Aha, I’ve also faced the ‘'USB Device Not Recognised’ on a front port when plugging in some USB sticks, while the same stick would work perfectly when plugged into a rear-mounted port directly connected to the motherboard, and discussed the problem way back in my October 2006 PC Notes column:

http://www.soundonsound.com/sos/oct06/a ... 1006.htm#3

Hope it helps!

Martin

[Rich Hanson]

I've also encountered the situation where a device sometimes doesn't get recognised when I plug it in. After unplugging and replugging it then works. Usually my 3G stick, but I have also seen it happen with a flash drive.

[Pete Kaine]

and discussed the problem way back in my October 2006 PC Notes column:

I've never seen that one before. Good to see a solid result in a mystery shopper situation too!

Yeah, tend to find on some boards that only the I/O plate mounted usb ports will give the full output as stated by the usb spec and sometimes the header ones that then get connected to the front panel can come up short. It use to be fairly common up until 3 or 4 years ago and now most of the previous guilty suspects seem to have their act in order. Always the first thing to try through as even previously working ports can be sporadic in detecting if not completely upto par.

[DragonLogos]

if it happens with any device it could be that the - data is in the + data place...

If can also be a faulty cable, ie Printer or Camera A to B cable

For front USB that sometimes and only with some devices plays up, it can be bad soldering on the USB board in the front, but most times it is down to the header wires are not good and are too long. In which case it is best to replace them with good copper wire and only as long as they need to be... like some beers USB does not travel well, which is true of a lot of stuff that has to go down wires... crossed pairs, bitter and twisted cables... LOL

If it is playing up front and back could well be the device is thinking of checking out on you

[DragonLogos]

BTW this is a famous fault for the HP 2015 laser - toner light comes on USB does not want to know and the service centre wants to sell you a formater board for just under the price of the printer... it can be fixed without too much drama... Was rather ticked that HP dodged the bullet on that one

[Martin Walker]

... like some beers USB does not travel well, which is true of a lot of stuff that has to go down wires... crossed pairs, bitter and twisted cables... LOL

What a lovely quote DragonLogos!

Martin

[DragonLogos]

Thanks Martin

Just a warning to anyone building up systems, or re-doing wiring to USB headers...

DO NOT REVERSE position Ground and +5v the result will be dire. Check it and check it twice, then test it before putting in a device LOL

[TheZman1]

I have had the same problem with the front USB port on my computer. Some devises work fine on the rear USB ports but not the front and some devises work fine on both. Reading the previous posts it sounds like the problem lies with the front ports being wired and the rear ports are physically mounted to the motherboard.

[Martin Walker]

Hi TheZman1, and welcome to the SOS Forums!

Yep - you’ve got it. It’s the extra length of thin wire connecting the front ports to the motherboard that seems to be the culprit. As DragonLogos mentions above, the ideal solution if you run into this problem is to replace that cable with something more ‘manly’ (i.e. thicker, with more copper, and only as long as it needs to be rather than with the excess coiled up in a corner).

By the way DL and Pete both - with your vast practical experience have either of you ever used twisted pair for USB front port data connections?

It does state in various places that USB High and Full Speeds can only be attained if special attention is given to screening and of having the data wires as a "twisted pair". This is presumably referring to USB cables, but it does occur to me that internal cables attached to motherboards headers ought ideally to comply with this as well. DO any motherboard manufacturers offer such screened/twisted pair header cable options?

Martin

[Pete Kaine]

Some of the older Silverstones (TJ05 did it I recall) had them although that would be going on for half a decade back now. Doesn't seem to be something anyone cares to impliment these days through.

[DragonLogos]

By the way DL and Pete both - with your vast practical experience have either of you ever used twisted pair for USB front port data connections?

It does state in various places that USB High and Full Speeds can only be attained if special attention is given to screening and of having the data wires as a "twisted pair". This is presumably referring to USB cables, but it does occur to me that internal cables attached to motherboards headers ought ideally to comply with this as well. DO any motherboard manufacturers offer such screened/twisted pair header cable options?
Martin

I rarely twisted cables for front USBs - It took me a while to work out the exact nature of the problem, but as said it was down to poor copper and keeping it as short as possible. The back header cables that you get from Gigabyte are twisted and have never had a problem from them

When making a cable shorter it is sometimes better to replace it with some really good gold coloured copper and solder the wires directly onto the front section

Another problem you can get with front USBs is when the plastic tooth gets broken off (the oblong plastic lock) this normally happens when a USB device is inserted and it gets a bump. You can replace these without too much effort, if you cannot get from your spares supplier you can always knock a few off scrap mobos

Have had PCs coming in that are dead only to find it was the front USB shorting out - a good visual check for PCs and notebooks