Need help hooking up front usb to motherboard?

Question

Hi Everyone,

I'm trying to figure out how to hook up front usb to a new motherboard (lose wires), and since I don't want to fry my motherboard, was hoping someone might offer a second opinion. The motherboard is an ECS nForce3-A v1.0

This is the wiring info provided in the motherboard documentation:
Pin 1 USBPWR (Front Panel USB Power)
Pin 2 USBPWR (Front Panel USB Power)
Pin 3 USB_FP_P0- (Usb Port 0 Negative Signgnal)
Pin 4 USB_FP_p1- (Usb Port 1 Negative Signal)
Pin 5 USB_FP_P0+ (Usb Port 0 Positive Signal)
Pin 6 USB_FP_P1+ (USB Port 1 Positive Signal)
7 GND (Ground)
8 GND (Ground)
9 Key (No Pin)
10 NC (not Connected)

Here are the cables I have (all lose) and colors:
Power (Purple)
Power (Black)
D2- (Brown)
D3- (Blue)
D2+ (Red)
D3+ (Green)
GND (Light Brown)
GND (Yellow)

I was thinking of doing this:
Pin 1: Purple
Pin 2: Black
Pin 3: Brown
Pin 4: Blue
Pin 5: Red
Pin 6: Green
Pin 7: Light Brown
Pin 8: Yellow

Does that look right? Does the order of the power and ground ones matter ?(meaning could I need to put black on pin 1 and purple on pin 2 instead?) Also, What are the last two pins, are they needed for anything? Also, does it matter how you put in the pin.. meaning does the side of the pin with the writing on it need to be on top or does it not matter?

I understand it's my risk if I try to do anything and I blow up the computer.. thanks for your help.

David
Edit/Delete Message

Answer 1

The standard USB connector pins on most motherboards
are one of 2 types, 4 pins in a row, or 5 pins in a row.

Since some CASES have a solid connector with a strangely
keyed plastic connector, and some MOTHERBOARDS
come with strange pin-outs, the manufacturers have started
separating the 4 or 5 wires so that you can manually
put the connectors on " ANY " set of pins.

It is actually easier than it looks, and the general rule of thumb
is that the USB pins on the motherboard are in this order:

POSTIVE 5 VOLTS, Negative DATA, Positive DATA, Negative GROUND.

( Positive, Negative, Positive, Negative. )

The END pins are Positive power supply + 5 Volts, and the other end is
Ground to the case .

The 5th end set of pins were originally another ground to
a braided wire around the outside of the USB cable itself,
as a sheild (the same as the braided outside wire on
TV/Satellite " 75 OHM " TV cable ).

I have a motherboard and case that someone blew up by doing
exactly what you are doing - putting 8 to 10 wires from the
front of a case USB plug onto the 8 to 10 pins on the motherboard. They put the 2 USB connector sets of wires in
with one row correct, ( +5, D-, D+, G ) and the other
reversed ( G, D+, D-, +5 ), and thus, shorted the entire power
supply's 5 volt rail to GROUND, since the USB "ground" goes to
the outter tin square around the USB plug, which is a motherboard / CASE ground. The wrong set of pins put +5 volt
to the connector, the correct set of pins put Ground to the
same spot, and the power supply blew, and the motherboard
was damaged... On most power supplies, the 5 volt rail ( the
RED wire in the connectors ) is the highest power output of the
entire supply, so that shorting it to ground is deadly.

All motherboards that I have worked with have 2 rows of pins,
and +5 is always on the same end, and one or 2 ground pins
are always on the other end. Since, in the ground end of the
2 rows, the 2 or 4 ground pins all go to GROUND / CASE,
whether or not you use 2, 3 or 4 of them is academic, and the
KEY, usually on the one row, on the 5th pin, and can be left off
the wiring, since it is just an extra ground going to the outter cable
sheathing... Now, more frequently, the cheaper cables do not have any outter ground sheathing at all, or, the shielding is soldered to the 4rth end ground pin.

If you can get a cheapo electrical meter, you can check that
the 3 odd pins on the end go to GROUND / CASE by putting
the meter on CONTINUITY, or on OHMS, and seeing that the
pins ( on one test lead ) short to CASE ( I use one of the
motherboard mounting screws as a " GROUND " ). Continuity
on a meter with a BEEP, will beep, or on the OHM scale,
should read ZERO OHMS ( a dead short ). ( ie, the pin you are testing is going straight to theCASE GROUND ).
Once you have established that one end is ground, then
the other end of the row is +5. ( You can also use a meter
to go to the +5 volt lead of any harddrive ( Red, Black, Black, Yellow = +5, G, G, +12 ) connector, and test that the end pin is
+5 ( Continuity to RED would BEEP, or OHMs would show Zero
OHMs from the end pin to the RED power wire ).

The rest is easy.

+5, Data -, Data +, and Ground on one row ( say USB 1 ),
then so the second row,
+5, Data-, Data+, and Ground on the second row. ( USB 2)

Your motherboard manufacturer uses the backplane USB as
ZERO and One, and the connectors you are using as 2, and
3. ( Binary, Digital counting uses 0, "ZERO", as the first
number, whereas, some manufacturers use USB 1, 2, 3, 4
etc. in Decimal numbers (( 0, 1, 2 and 3, are the same as 1,2,3 and 4... )

Some motherboard manufacturers use the ROW as
pins 1 to 5, and the second ROW as pins 6 to 10,
while others use SETS of 2 pins beside each other
as 1, 2 then 3, 4 etc, as in your instance.

Realizing that the ROW goes +,-,+,- is the key.

Having an electrical meter to verify that the end pins
are either +5 or to GROUND, is VERY handy, and
I have gotten a few motherboards where the PDF
motherboard diagram IS WRONG !!! and if followed
closely, would blow up the board/ and/or/ Power supply...!!
( Someone copied the diagram from the last model,
without checking )

I think you have the wiring correct, but take your time,
and do the USB one ROW at a time, carefully reading
all the USB 1's, +,-,+,-,
then the second row, USB 2's, +,-,+,-

and I think you will be fine.

The key, or missing pin, is usually on the Ground end, since it is
redundant..

Meters are about $8 to $10 at places like Canadian Tire,
Princess Auto, Fry's, Wal Mart, etc. - ( I don't know where in the world you are located ). A meter with a
"BEEP" little annunciator on Continuity is extremely handy
since you don't have to LOOK at the meter while
using both hands to place the test leads. These may cost
a bit more, but are well worth the price. Liquid Crystal
Digital displays are usually ok for most computer applications.

Thank you for providing really great information.

hope this helps

robin

Answer 2

From the appearance of the information you provided, what you are thinking looks correct to me. I've built many computers so I know what risks you are taking here but I think you're safe.

As far as the power and ground cables, you don't have to worry as long as they're plugged in. If they needed to be separated, they would have been labelled slightly differently on the cable itself or on the motherboard itself.

I'm not too sure of the last two pins, but you probably don't have to worrry about them. You have the correct cables you need for the USB ports.

Second thing to look for as well....some Motherboard have switches that need to be set correctly to enable front USB ports. Make sure you have those set correctly (if you need to) or the USB ports will not work even hooked up to the Motherboard correctly. Check the motherboard documentation first.

Answer 3

You should have a complete cable that plugs into the front side USB configuration and the motherboard, the motherboard installation manual should clearly identify the usb interface pins and which pin is pin 1 ... which gets the other end of the cable plugged into it. If you don't have this I would contact whoever sold you the motherboard and request a cable.

Answer 4

If you have the manual that came with the mobo, look in there. It will tell you EXACTLY how those little plugs go onto those little pins. Do not hook up your fire-wire to the USB pins or visa-versa, or you WILL fry the mobo.

Answer 5

it may be good that you need to get an Xbox 360 chatpad rather of a instantaneous keyboard. in case you insist on having an complete sized one then use the decrease back USB port. Xbox Chatpads are really sensible although.