Motherboard won't power on with usb header plugged in

[Sonikku]

I'm getting a new system together and I've noticed it won't power on when I plug in the USB 2.0 header from my case onto the appropriate prongs on the motherboard.

http://www.newegg.com/Product/Produc...82E16813157303

http://www.asrock.com/mb/Intel/H77M/?cat=Specifications

It took me quite a while to find out what it was that was causing it to not power on at all, not even the fans. I noted that when I removed the usb header from the motherboard it fixed the problem and the power button activated the machine. What could cause this? Will I have to use my machine without having the convienience of two usb inputs on the front of my case? I noticed the problem happens whenever I plug it onto either of the two usb prong arrays on the board.

 

[ch33zw1z]

Did you get a USB accessory with the motherboard? sorta like this:

If so, plug that in and see if you get the same problem.

If you do, probable motherboard RMA.

 

[Sonikku]

I didn't get any such accessory. I've never had this happen before. If they didn't work, wouldn't the machine still at least be bootable? Sure the front usb inputs wouldn't work, but I've never heard of a non functioning usb header rendering a board unable to even power on. Yet it powers on just fine with the front usb header unplugged.

 

[ch33zw1z]

Power is everything. If those front USB's are causing a problem then it's entirely likely to cause the problem you're seeing. Determining the source the issue is key.

Are the front USB's block connectors, or is it 7 individual connectors, 1 for each pin on hte USB headers?

 

[Sonikku]

It's individual little pins. Here is a pic

 

[ch33zw1z]

Right, but the cable from the Case plugs. Are they block connectors, or individual connectors?

 

[Sonikku]

I'm sorry, I guess I am ignorant of the difference in usb header cables. The header from my Antec Sonata 2 case looks like the one on the right.

 

[ch33zw1z]

Those are different headers, fyi. USB is just that USB, 1394 is Firewire.

Back in the day, those connectors were typically individual pin connectors that you have to put in the right spots.

If they're block connectors, hard to mess it up. USB uses 9 pins, make sure it's plugged in the right way.

If it is plugged in the right way, and you get no POST/No Vid, then try Clearing the CMOS and booting again.

edit: sorry 9 pins, not 7!

 

[Dahak]

Just looking at your first pic, are you not inadvertently connecting the usb header to the pins on the board on the lower 4 pins(the gray ones) if so that could cause and issue as that is a different connector.

to help visualize it - = open pins x = connected with front usb header
-----
xxxx
xxxx

or you can try it on the one header to the left usb8_9

 

[Sonikku]

Yeah, I thought of that and was very careful not to latch it onto the infrared header thingy beneath it. I even tried hooking up the usb header on the left array on the motherboard that has no such 4 pin layout beneath it. Same results.

Those are different headers, fyi. USB is just that USB, 1394 is Firewire.

Back in the day, those connectors were typically individual pin connectors that you have to put in the right spots.

If they're block connectors, hard to mess it up. USB uses 9 pins, make sure it's plugged in the right way.

If it is plugged in the right way, and you get no POST/No Vid, then try Clearing the CMOS and booting again.

edit: sorry 9 pins, not 7!

I'll try that, though it's not just a question of no post/video. The fans don't even start spinning if the header is plugged in. The machine is just dead as though the power cord was removed.

 

[ch33zw1z]

If that doesn't work, try to get one of these: http://www.amazon.com/StarTech-com-F...sxp_grid_i_0_0

You should also pull the motherboard out and make sure that there's no standoffs sitting underneath the USB headers, or in positions that don't line up with the motherboard mounting holes. That would definitely cause a problem.

 

[pauldun170]

I have this problem with my Rosewill R10whatever the number is.
In my case, its the usb ports on the case that are bad.

 

[Drako]

Shorting 5 volts to ground is never a good idea .

 

[Vinwiesel]

If you have a multimeter, set it to ohms and measure 5v to gnd on the motherboard with the system off. Then plug in the usb header and see if the resistance goes to near zero. As mentioned above it really sounds like the cable is shorting out the 5v supply, preventing boot.

Way back when there were some oddball USB headers which were wired non-standard, possibly for oem systems. Sometimes these show up on ebay and amazon and people are hosed when they try to use them in a modern system. Your case doesn't sound old enough to be suffering from that, but who knows. If it is a used case, somebody could have rearranged the wires inside the connector to fit some certain board.

 

[Sonikku]

it is a used case, but it has only ever been mine. The usb headers allowed me to use the front usb inputs on the case in the past with the motherboard I took out and replaced the new one with.

 

[mfenn]

Shorting 5 volts to ground is never a good idea .

:thumbsup: This is probably what is happening. Get a multimeter with precision probes and measure the resistance between the +5V and GND pins on the USB front panel cable (all +5V and GND combination). They should all show an open circuit (with no USB device plugged in of course). If there is low resistance between any pair, that's your problem.

 

[jbosari]

I'm pretty sure this is a simple problem of not plugging in the USB connectors correctly. I switched cases and had the same problem. You don't plug each one into a separate USB socket.The solution was to plug each USB connector, one stacked atop the other, into a single USB socket (one on top and one on bottom). I think that's what Dahak was getting at. My other case had both USB connectors in a single plug that fit the USB socket perfectly. My new case has two individual USB connectors that have to be stacked one on the other. If you don't do it that way, PC won't start.

So, we have a single USB socket with pins (x) and an unused spot (-) that looks like this:

-xxxx
xxxxx

I don't know why that 9th pin is hanging out there on the left, but it's probably part of the confusion.

Each of the female openings (0) on the two usb connectors goes in this one socket. You just have to stack one on top of the other and ignore that pesky 9th pin.

Each USB connector looks like this:

0000

Plug in USB #1 and it looks like this:

-0000
xxxxx

Now plug the second USB connector in below and it looks like this:

-0000
x0000

I hope this makes it a little clearer. Fixed my problem anyway. Now if I can get than dang HDD LED or even the Power LED to work, I'd be satisfied

 

[mfenn]

Locked as necro.

mfenn
General Hardware Moderator