[SOLVED] USB 3.0 Expansion PCI-e card killing USB Drives. Differential diagnosis?

[navienavnav]

I bought a USB 3.0 PCI-e internal expansion card off eBay because my computer didn't have USB 3.0 ports. It also has a molex 4-pin connector.

I installed in on my machine (also plugged the molex 4 pin connector to an unused one branched off the hard disk connector) and plugged my brand new Transcend 32 GB USB 3.0 flash drive in it and it went completely dead. Didn't work anymore. I (stupidly) inserted another flash drive lying around (USB 2.0) of 4 GB size and it went dead too. (Good thing I got my new one replaced under warranty lol)

Now, it got me thinking. What could be the reason for this? The only thing I could come up with (considering the quickness and similarity in which how both the USB drives got destroyed) is that somehow very high current went through the devices to fry them.

Have you encountered such a situation before and do you know of any other reasons this could happen.

In case, the issue is about the current being delivered, if I disconnect the molex 4-pin connector, can the PCI-e interface connector provide enough power to fry the device (assuming the device expansion card was drawing more power than it should.) ?

Additionally, is there any type of circuit I can come up with to protect the USB drives from overcurrent (if that's the case)?


Obviously, the above mentioned solutions apply only if the problem is indeed about overcurrent. Let me know if you think it's anything else.

Thanks.

 

[navienavnav]

I just measured the short circuit current output from the USB ports and also the open terminal voltage.

Without molex connector the current is about 2.4A (SHORT CIRCUIT CURRENT!) and voltage around 5.3V.

With molex connector, the voltage showed to be 12.33 V!!! I was worried about short circuit current being too high so I didn't measure it in this case.


So, I think I've found the problem.


I also checked for the same on a working USB 2.0 port I originally have on the motherboard and the voltage was 4.98 V and current (short-circuit) was 1.85 A.

So, I guess, without the molex connector, my USB 3.0 expansion card should be fine. However I am scared to plugin my newly replaced flash drive

I'll fetch some really old n cheap flash drive tomorrow to test which is dispensable. If everything works, I'll mark this as solved.

 

[tpetar]

USB port should have 5,00V or near that 4,98V-4,99V but not 5,3V!

In other hand, maximum current (short circuit current) what you measure dont have nothing with current what is/will be used by some device such as flash drive. Current in circuit will depends on resistance in circuit.

Additional its not smart to drain lots of current over main board.



Check product quality, maybe you have bad designed product, bad clone or faulty device.


Best regards,
Peter

 

[FvM]

Missing current limit won't kill a healthy USB device, VBUS maximum voltage is specified as 5.25V. 5.3V usually still won't hurt. But 12V ...

I have been already wondering about the "molex connector". You mean the peripheral power supply connector used with 5.25" HDD and FDD? Can it be that you have the 5 and 12 V wire interchanged at your connector? Otherwise it's apparently a defect or design error of the USB card. Besides killing the USB device, the overvoltage might have damaged the controller itself.

 

[navienavnav]

Hello hello.

It's working just fine without the molex connector. All the devices, including the flash drive that was replaced, are working fine without the connector. The connector is a Molex 8981 Power connector (female). I am 100% sure I had connected the connector with the correct orientation. It could be that the PSU is supplying incorrect voltage to the 5V pin but that's unlikely because everything else on the computer is running just fine.

Nonetheless, I am finally using my 3.0 ports just fine and since I don't use those ports to charge a high powered device, I don't think I need the external supply using the connector. So I'll mark this as solved.


Is the 5 +/- 0.25 V specification after the voltage drop or is it the open terminal voltage at the port?

 

[FvM]

4.75..5.25 V is the allowed voltage range in operation at the host connector. There is an additional budget for voltage drops of cables and bus-powered hubs.

 

[123jack]

I have a similar 2 port USB3 board but have had no problems.
I suspect the molex is used to ensure there is sufficient current available.
Remember that USB3 uses more than USB2 and some USB3 devices use a lot more.
(The plug recommended is indeed the old floppy connector FVM)

Mine is configured to provide up to 900mA per port
as opposed to the 500mA I'd expect to see as a maximum on a USB2 port.

You might find some USB3 devices will work without the molex but others will not.

 

[tpetar]

Navienavnav did you use USB 3.0 cable for USB 2.0 devices ?

You can kill USB 1.1 2.0 devices like rabbit if you use USB 3.0 cable for them on USB 3.0 Host.


**broken link removed**




Best regards,
Peter

 

[navienavnav]

You might find some USB3 devices will work without the molex but others will not.

So far, all the devices are working without the help of power from the molex connector.

- - - Updated - - -

Navienavnav did you use USB 3.0 cable for USB 2.0 devices ?

You can kill USB 1.1 2.0 devices like rabbit if you use USB 3.0 cable for them on USB 3.0 Host.


**broken link removed**


Best regards,
Peter

Hello Peter, I don't know where the cables come into the picture in my case. I, as an installer, did not come across any such cables. It's just an expansion card which goes into the PCI-e port the back side of which has two USB3.0 ports where devices can be plugged in. Were you talking about different types of molex connectors?

 

[tpetar]

No, I talking about USB cables, because you use PCI card which gives you additional USB 3.0 ports but from back side. Usually case is on floor or somewhere or on desk but is not practical to access to back side of PC case, and for this situation people use USB cables such these cables for example :


USB 1.1/2.0 AA AB

USB 3.0 AA AB
**broken link removed**



Best regards,
Peter

;-)

 

[FvM]

I fear the diagram in post #8 together with the photo in post #10 is rather confusing the problem of USB 2.0/3.0 compatibility.

The photo is showing an AA extension cable (a cable that doesn't exist in the USB specification, by the way). The type A host connector is up- and downward compatible between USB2.0 and "super-speed" USB 3.0 by specification. Means you can insert a 2.0 plug into a 3.0 host jack and vice versa.

The incompatibility exists for the type B device connector. The type B device connector has a different outline and is mechanically incompatible. Or as the USB spec says "Inserting a USB 3.0 Standard-B plug into a USB 2.0 Standard-B receptacle is physically disallowed".

The connector face clarifies why you can hardly insert the wrong connector without using a hammer...

 

[pjmelect]

I dispute tpetar claim that having a USB3 host and USB 3 cable can damage a USB 1.1 or 2 device. I have a USB 3 host and cable, which I have plugged many different USB 2.0 devices without problems. I don't see how by using a USB 3 cable and hub on a USB 2.0 device can cause any problems as they use a different set of pins on the connector.

 

[123jack]

As someone pointed out - a USB3 cable has a notch to preven it being plugged into a USB 1 or 2 device.
I've never looked into it but I assume that was done for a good reason.
I guess wikipedia would explain it to anyone interested enough.