PSU Causing USB Port Issues?

[The Merg]

I have a Dell Dimension 8300 with Windows XP-SP3 that I am working on. I am having an issue with USB devices causing the system to hang when they are plugged in (whether it is any 6 on the back or the 2 on the front). There are a few times the system has not hung, but it does not recognize that anything is plugged into the system when that happens. The owner of the desktop stated that he thinks he has seen a pop-up from the system tray about a power surge on the USB Hub before when trying to use a USB device. I have also noticed a few times that the power light on one of the USB flash drives I am using does not come on all the time.

I started to think that it might be PSU issue, so I tested the voltage while under load. My results were:

3.3v: 3.35v
5v: 5.11-5.12v
12v: 11.86-11.89v

It looks like the PSU is still within specs. Does anyone have any ideas as to what may be the issue here? Is it possible that the low voltage onthe 12v rail is still causing the problem. I have uninstalled and reinstalled the ports and Hub in Device Manager in XP to no avail.

I know that this might not actually be a PSU issue, but figured I'd start here first. Any ideas would be appreciated.

Thanks,
Merg

 

[Modelworks]

Welcome to AT !

Look on the motherboard for the fuses that protect the usb ports. They are usually marked as F1, F2, F3, etc and will be close to where the usb ports connect. See if there is anything suspicious, burns, solder cracks, etc. And check the cables inside the case that connect the extra ports as well.
12V doesn't have anything to do with usb, and the 5V looks fine.

In this picture the fuses are the ones with the P.
http://www.newegg.com/Product/...therboard%20-%20Retail

 

[The Merg]

Thanks for the reply. I didn't think the 12V had anything to do with the USB ports, but I'd figured I'd ask. I'll check the fuses when I get home tonight. As for the cable connecting the extra ports, I don't think that's an issue as the problem occurs whether you use the front (extra) ports or the ones on the back.

If one of the fuses is damaged, would that affect all the ports or are the fuses associated with a specific port?

Thanks again,
Merg

 

[Modelworks]

Each fuse powers a hub that can have several ports off of it. So one fuse may be powering 3 ports.

 

[The Merg]

Direct.

Just so that I don't have to keep bothering you guys, are there any other causes to this issue that you can think of?

Thanks,
Merg

 

[Zap]

Originally posted by: The Merg
3.3v: 3.35v
5v: 5.11-5.12v
12v: 11.86-11.89v

Have you tried the 5VSB? It should be 5v of course, and is the purple wire on the main motherboard connector. I believe USB runs off that.

 

[Zepper]

USB ports can be jumpered (or perhaps switched by a BIOS setting) to operate during powered down situations by connecting them to the 5V Standby line instead of the normal 5V line. That can cause problems if you have high draw items connected to your USB ports. May need a PSU with stronger 5VSB rail if high-draw items are a must (or connect them to self-powered (i.e. has its own wall wart) hub(s) to take the load off the 5VSB line.

.bh.

 

[The Merg]

Well, I found no obvious issues with the fuses on the motherboard for the USB ports. Also, the 5VSB rail registers at 5.01-5.02V under load.

The only thing I can think of would be an issue with the Motherboard itself, something I really don't want to have to tell the owner. I suppose I could get a USB Hub PCI card to see if the issue is still there, but I'm 99% positive it is not a software/driver issue.

Thanks for the suggestions. Any more by chance?

- Merg

 

[Painman]

I'm not 100% sure if a transient short could cause this (seems like it would just blow one of the fuses) but it may be worthwhile to pull the mainboard, look for improperly clipped component leads on the backside, etc., and try running it on a piece of cardboard just to rule out the possibility.

 

[The Merg]

Even if one of the fuses was blown, it still wouldn't explain why I am having the issue with all of the ports.

- Merg

 

[Painman]

All the more reason to isolate the MB electronically by testing it outside of the case... Stop posturing (and wasting your client's time/$) and just do it.

 

[The Merg]

Originally posted by: Painman
All the more reason to isolate the MB electronically by testing it outside of the case... Stop posturing (and wasting your client's time/$) and just do it.

I wasn't disagreeing with you. I haven't been able to get ahold of my client to let him know what's going on, so I don't even know yet if I'll be doing any more work on it yet.

I appreciate all the help.

- Merg

 

[Painman]

Originally posted by: The Merg

Originally posted by: Painman
All the more reason to isolate the MB electronically by testing it outside of the case... Stop posturing (and wasting your client's time/$) and just do it.

I wasn't disagreeing with you. I haven't been able to get ahold of my client to let him know what's going on, so I don't even know yet if I'll be doing any more work on it yet.

I appreciate all the help.

- Merg

I'm Sorry. I've been spewing personal stress out on the forum lately, and not really realizing that I've been doing so. Maybe I need a break...

Extra Special apologies because you're new here, and this is actually a good place to hang out and pick up tons of tips.

Please, stick around. Don't mind me.

 

[The Merg]

Don't worry. I didn't take it personally. I've been around the forums long enough...

As for this issue, my client opted to just have a PCI USB Hub installed since it's only $13. A lot less than trying to narrow down the cause of this issue. Makes my job easier, too.

Thanks again,
Merg

P.S. I'll be up on here a lot more in the coming months. Great advice and tips here.

 

[The Merg]

Figured I'd just follow-up to let people know that the PCI USB Hub worked fine. There was definitely an issue with the USB ports in the computer. I found a lot of other posts on people complaining about issues with their USB ports on their Dimension 8300's.

I still don't know if it was a power issue (all tests indicate otherwise), but it does seem like a hardware issue with this particular model.

- Merg