Improving front USB reliability

[Slater]

My PC's front USB assembly is very unreliable. It looks like this:
http://i00.i.aliimg.com/img/pb/398/041/436/436041398_510.jpg
Basically it's just a straight connection. USB devices attached to it
tend to disappear and reappear at random.
I had a look at an Asus backplate USB assembly that works much better
and tried to draw a schematic out of it:
http://s10.postimage.org/872gumprd/usb_filter.gif
Though I'm unsure about some of the values. L1 and L2 are SMD parts
and are marked "4.3" and "100" respectively. C1, C2 and C3 are SMD too
but they have no markings and I tried measuring them with a lousy
multimeter.

Do you think the circuit I drew might do? Can I use a 4.7uH coil
instead of 4.3? What would you do if you should start from scratch?
Thanks.

 

[hamilton]

Flip it over and resolder all the connections. Never mind if the
connection looks good. Just hit everything with a soldering iron.

Pull on all the crimp pins.

If its loose, its broke !

 

[Raveninghorde]

My PC's front USB assembly is very unreliable. It looks like this:
http://i00.i.aliimg.com/img/pb/398/041/436/436041398_510.jpg
Basically it's just a straight connection. USB devices attached to it
tend to disappear and reappear at random.
I had a look at an Asus backplate USB assembly that works much better
and tried to draw a schematic out of it:
http://s10.postimage.org/872gumprd/usb_filter.gif
Though I'm unsure about some of the values. L1 and L2 are SMD parts
and are marked "4.3" and "100" respectively. C1, C2 and C3 are SMD too
but they have no markings and I tried measuring them with a lousy
multimeter.

Do you think the circuit I drew might do? Can I use a 4.7uH coil
instead of 4.3? What would you do if you should start from scratch?
Thanks.

I have a different problem. We put together 3 new quad core PCs. If
you use the front connectors ESD freezes the PC.

 

[JW]

My PC's front USB assembly is very unreliable. It looks like this:
http://i00.i.aliimg.com/img/pb/398/041/436/436041398_510.jpg
Basically it's just a straight connection. USB devices attached to it
tend to disappear and reappear at random.

I'm not surprised. Ribbon cable for USB 2.0? How long is the cable? I
wouldn't connect any USB 2.0 device to that.

 

[Johann Klammer]

I have a different problem. We put together 3 new quad core PCs. If
you use the front connectors ESD freezes the PC.

Just guessing,
Did you check the connector pinouts actually match the mainboards headers?

 

[Slater]

I'm not surprised. Ribbon cable for USB 2.0? How long is the cable? I
wouldn't connect any USB 2.0 device to that.

It's about half a meter, although mine has tinfoil-like shiled and a
plastic jacket around it. The tinfoil isn't connected to ground,
though.

 

[JW]

It's about half a meter, although mine has tinfoil-like shiled and a
plastic jacket around it. The tinfoil isn't connected to ground,
though.

Does it work OK with USB 1.1 devices (keyboards and mice)?
If it does, and gets flaky with 2.0 devices, I would bet on the cable not
being apropos for USB 2.0.

 

[Slater]

Does it work OK with USB 1.1 devices (keyboards and mice)?
If it does, and gets flaky with 2.0 devices, I would bet on the cable not
being apropos for USB 2.0.

I can no longer test it because I installed a better and shorter cable
with proper shielding and it's working perfectly!