I had to change the motherboard as it failed

Great that the problem is solved. You can't close this thread. Just leave it.

Hello here is the homepage:

http://h10025.www1.hp.com/ewfrf/wc/product?cc=us&lc=en&dlc=en&tmp_geoLoc=true&product=4120042

The front panel connector look like this:



It`s located down the right corner of the mainboard.

Good luck

HP Support > Pavilion Media Center M8100n Desktop PC > Main Support page,

http://h10025.www1.hp.com/ewfrf/wc/product?product=3440614&lc=en&cc=us&dlc=en&lang=en&cc=us

Product information > Product specifications > Motherboard Specifications, MCP61PM-HM (Nettle2 {HP name} ),

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01077676&tmp_task=prodinfoCategory&cc=us&dlc=en&lang=en&lc=en&product=3440614

The front of your computer is the Front Panel.
The area of contact pins on the motherboard, that the Main wires connect to, is the Front Panel header.
(Power On switch, Power On LED, HarDDrive activity LED, etc)

The Front Panel header is Black, rectangular in shape, and is situated in a vertical position; located in the Bottom Right corner of the motherboard. (Next to the mounting hole)

It is a standard 9-pin HP Front Panel header,

http://h30434.www3.hp.com/t5/Desktop-Hardware/Getting-a-new-case-i-need-Front-Panel-pinout/td-p/842897

Scroll down to the 9-pin Front Panel header photo, and pinout.

The 4-pin side is the EVEN side. Pins 2, 4, 6, and 8. There is NO Pin 10.
The 5-pin side is the ODD side. Pins 1, 3, 5, 7, and 9.

A) Pins 1 and 3 are for the HarDDrive activity LED. (Light Emitting Diode, so it is redundant to call it a light)

Pin 1 is for the Positive ( + ) wire.
IF the HDD LED is dim when the harddrive is active, (IN use), switch the wires around.

B) Pins 5 and 7 are for a Reset switch, IF a Reset switch is used.

C) Pin 9 is N/C. Not Connected. Reserved for factory use, and it is +5 Volts.

D) Pins 2 and 4 are for the Power On LED.
Pin 2 is for the Positive ( + ) wire.
If the PWR LED is dim when the computer is on, switch the wires around.

E) Pins 6 and 8 are for the Power On switch.

Scroll the HP Support Motherboard Specification page down. Click on the + sign next to Motherboard Layout.

Left to Right on bottom edge of motherboard, Internal Connectors;

AUDIO_1 is for the audio ports on the Front Panel.
ATX_IN is where the small audio cable from the optical drive plugs in.
(CD/DVD drive)
IF TWO optical drives are used; the Main, or Primary optical drive, is connected with the small audio cable. NOT the secondary optical drive.

HD_AUDIO also connects to audio ports in the Front Panel.
May be mistaken, but don't believe SPDIF_OUT header is used.
1394A1 header is for the Firewire ports in the Front Panel (1394a)
USB 2 and USB 4 headers are for the Front Panel USB ports.
USB 1 and USB 3 should be for a Card Reader.

Need where the power cables go, and what they look like? Just post back in a Comment.

(Be SURE to FOLLOW Anti-Static Precautions)

Regards,
joecoolvette

[ Didn't think you actually wanted an actual circuit diagram. That is copyrighted by HP, and Elitegroup Computer Systems. (ECS)

The Asus A8M2N-LA motherboard was made SPECIAL for HP.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00757531&tmp_task=prodinfoCategory&cc=us&dlc=en&lang=en&lc=en&product=3339286

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00820191&tmp_task=prodinfoCategory&cc=us&dlc=en&lang=en&lc=en&product=3339286

As such Asus has no info on it.

Looking at the second link posted (Motherboard Specifications), scroll down to the bottom, and click right on - Motherboard Layout

Motherboard layout shown (Direction), is the same as is installed in your computer; Processor to the Top, white PCI slots to the Bottom, Ram Memory to the Right.

The plastic front of your computer is the Front Panel.
The area of contact pins on the motherboard, that the cables (Wires) go to from the Front Panel, is the Front Panel header.

Abbreviated F_PANEL 1, at the bottom right corner of the motherboard, is the Front Panel header.

There are 9 contact pins. Two rows.
Across the Top row they are numbered ODD.
Across the Bottom row they are numbered EVEN.

Coming from the Left side of the motherboard towards the right side, on the Top row;
Pins 1, 3, 5, and 7

Coming from the Left side of the motherboard towards the right side, on the Bottom row;
Pins 2, 4, 6, 8, and 10.

A) Pins 1 and 3 are for the HarDDrive activity LED light.
Pin 1 is for the Positive wire. ( + )
If the HDD LED is dim when operating, switch the wires around.

B) Pins 5 and 7 are for a Reset switch, IF a Reset switch is used.

C) Pins 2 and 4 are for the Power On LED light.
Pin 2 is for the Positive wire.

D) Pins 6 and 8 are for the Power On switch.

Regards,
joecoolvette

Remove the side-panel.
Look for the many wires that run from the front-panel to some connectors on one corner of the motherboard. Two of those wires connect to two pins labelled 'POWER' or 'PWR'.
Remove the two wires. Take a metal screw-driver, and touch both exposed pins, for an instant.
This simulates pushing the 'ON/OFF' button.

If this works, go to any electronics store, and find a new ON/OFF "momentary" switch,
buy it, and connect it to those 2 pins.

The HP m7260n has an SPDIF connection on the motherboard. It's near the spot where the VGA port is connected to the board. I suspect that is what you need. The layout diagram for the P5LP-LE is available here: https://support.hp.com/us-en/document/c00864946 .

The specifications, including the motherboard information, for the m7260n are available here: https://support.hp.com/us-en/document/c00507225 .

I hope this helps.

Cindy Wells

Open your computer casing where the motherboard lies in and then remove the memory card, your new video card and then reset the BIOS, refer to the motherboard manual on how to do it. After resetting, plug in the memory card and video card. Close the casing and connect all the wiring. Power up your computer.

I am not familiar with your exact motherboard, but most commonly, the front panel connectors themselves usually have white print labeling them, and on the motherboard, similar fine white markings will be next to the appropriate pins. This is not always the case, but the front panel pins on the motherboard are usually located near the bottom right hand corner.

Not trying to give you a flippant answer, but what sort of diagram?
Troubleshooting diagram? Motherboard diagram? Diagram of how the cables connect inside?
Hmmm, let me see,

1.Troubleshooting and System Recovery Guide,
http://h10025.www1.hp.com/ewfrf/wc/manualCategory?lc=en&dlc=en&cc=us&lang=en&product=470506&
2. Motherboard specifications table Motherboard layout and photos Clearing the CMOS settings Clearing the password settings
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00379422&lc=en&dlc=en&cc=us&product=470506&lang=en
3.HP.com/Support and the main page for the HP Media Center m7160n Desktop PC,
http://h10025.www1.hp.com/ewfrf/wc/product?product=470506&lc=en&cc=us&dlc=en&submit.y=8&submit.x=6&lang=en&cc=us

You might need to open the case and make sure that the wires going from the power button are actually connected to the motherboard.