Loose Cap causing 2 dead USB ports?

[t3chb0y]

I got a ECS board from ebay and I noticed that one of the caps near the rear IO had its "-" negative side detached...Could this be responsible for 2 dead USB ports in the rear IO? Would they work if I got a new capacitor (with the same ratings) and soldered it back together?

Or would the 2 dead USB ports be caused by something else?

[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

Yes and Yes.

Cap could be it. Could be something else.

One way to find out.

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[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

Usually USB ports go dead because someone pulled too much power through it and fried the USB chip. (They are only rated for 500 milliamps.)

A bad (effectively missing) cap could be affecting the power to the chip or it might be a coupling cap that the USB signal passes through.

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[t3chb0y]

Re: Loose Cap causing 2 dead USB ports?

Usually USB ports go dead because someone pulled too much power through it and fried the USB chip. (They are only rated for 500 milliamps.)

A bad (effectively missing) cap could be affecting the power to the chip or it might be a coupling cap that the USB signal passes through.

.

with that said...does that mean the 2 USB ports aren't receiving power due to the loose cap since I get absolutely no signal plugging virtually anything that's USB in.

[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

I don't know where the cap is in the circuit.
I can't tell you anything for sure without tracing the circuit.

Yes, if the chip is not powered it can't pass the signal.

Same-same.
If you modem chip or LAN chip isn't getting powered it can't pass a signal.



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[t3chb0y]

Re: Loose Cap causing 2 dead USB ports?

it's the most upper-left cap on the board (right next to the top left screw hole and beside the PS/2 ports)

[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

Ummm
I don't see a picture.
Nor do I know what model board it is to go find a picture. (If I had time.)

Even still I can't trace a circuit by a picture.

You should just re-attach or replace the cap and see if you get your port back.

You are gonna have to do that anyway so,,,, Go for it!



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[tvtech]

Re: Loose Cap causing 2 dead USB ports?

Also look for miniature fuses near the usb ports,they come in all sizes and varieties,some look like SMD resistors some look like tantalum capacitors and some look like ceramic disc capacitors.I will post some pics of microfuses on a mobo tomorrow.Most boards have fuses protecting the +5v line for the usb.If you dont find any fuses and the cap replacement doesn't restore usb function you can always turn off the on board usb controllers and use a PCI usb 2.0 card.

[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

tvtech
Now that's an outstanding idea.
The start of the thread though is about detached caps.

Do you (or anyone) happen to have a schat for the USB section of a mobo that includes the IC and power to it?

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[yanz]

Re: Loose Cap causing 2 dead USB ports?

Also look for miniature fuses near the usb ports,they come in all sizes and varieties,some look like SMD resistors some look like tantalum capacitors and some look like ceramic disc capacitors.I will post some pics of microfuses on a mobo tomorrow.

please do so, thanks in advance.. i got several ecs mobo with dead usb port. recaping the caps wont fix the problem.

yep, for the time the only solution for me is to use addon pci usb card..

[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

yanz

Did you check for those fuses tvtech mentioned?

Dead USB ports comes up all the time. It would be nice to find the fix for it.
Unfortunatly (umm.. sort of) I don't have any boards with dead USB ports to play with.

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[PCBONEZ]

Re: Loose Cap causing 2 dead USB ports?

yanz

Did you check for those fuses tvtech mentioned?

Dead USB ports comes up all the time. It would be nice to find the fix for it.
Unfortunately (umm.. sort of) I don't have any boards with dead USB ports to play with.

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[tvtech]

Re: Loose Cap causing 2 dead USB ports?

Sorry for the wait I WILL post pictures tomorrow,As for the schematic of the usb ports,you may have some luck getting a datasheet for the usb controller chip at www.datasheet4u.com and you could then trace the +5v line.Other that that I know that some early boards had the +5v rail feeding the ports directly and today most of the boards use the usb chip to switch the +5v off and on and some well desinged boards have seperate 5v regulators feeding each pair of usb ports

[yanz]

Re: Loose Cap causing 2 dead USB ports?

Did you check for those fuses tvtech mentioned?

Dead USB ports comes up all the time. It would be nice to find the fix for it.
Unfortunately (umm.. sort of) I don't have any boards with dead USB ports to play with.

To tell u the truth i dont know what is what So a pic would help...

[t3chb0y]

Re: Loose Cap causing 2 dead USB ports?

my friend got one of the rubycon caps I ordered and soldered them on for me....apparently the USB ports are still dead.

[kc8adu]

Re: Loose Cap causing 2 dead USB ports?

my friend got one of the rubycon caps I ordered and soldered them on for me....apparently the USB ports are still dead.

carefully probe the ports and see if +5 is present.if not the fuse is blown.
most have polyfuses which reset after a short.
a busted port that is shorted is common too.
edit.
ecs is a cheapie board.
they may not even have fuses!
a short blows the foil to +5.
if they have fuses they may be one time which must be replaced.