When connected to the electrical supply, one touch of the power button or the area nearby produces a quick light on light off of the panel. The machine does NOT power on.

Sounds like you have a control logic issue. Either a button on the control panel is stuck, or the control board is defective. Find the model number on the unit and post it in the comments please.

This Foxconn 915M08-G-8KS motherboard made for Acer Veriton desktop computers?

http://www.sella.co.nz/general/computers/components/motherboards/other-motherboards/b1jnj6/

Do not know what the Front Panel header pinout is.

(Front plastic part of computer tower is the Front Panel.
Area of contact pins on the motherboard, that the wires (Cables) from the Front Panel connect to, is the Front Panel header )

CAN see by clicking on - View full size image - that the Front Panel header is to the Top Left corner of the motherboard, by the CMOS battery.
(View of mobo is upside down, in relation to how it actually sits in the computer tower case)

Shows me it is just the normal two rows of contact pins used in a LOT of desktop computer mobo's. (MOtherBOard)

If it were I, I would use one of the LED lights connected to two wires, and touch across each two sets of pins.

Looking at the motherboard as it sits in the computer case, there is a row of pins on Top, and a row of pins on Bottom.

In your mind start at the LEFT side of the pins at the TOP.
Number them from Left to Right.
Example, Pins 1, 3, 5, 7, and 9.

Now number the pins on the Bottom, from Left to Right,
Pins 2, 4, 6, 8, and 10.

Computer plugged into power, touch the two wires of the LED light, to Pins 1 and 2.
Computer doesn't start? (Power Supply turns on)
Go to the next set of pins.

I am willing to bet Pins 5 and 6 turn the Power Supply on.
No? Keep experimenting.

What will happen if you touch the WRONG pins?
N-O-T-H-I-N-G
You will NOT hurt the motherboard.

When you get to the correct pins, the Power Supply will turn on.
These pins are for the Power On switch.

Now go back through the pins with the Power Supply on, but DO NOT touch the pins that turned the Power Supply on.

When the LED light STAYS on, you have the pins for the Power On LED light.

If the LED light BLINKS, you have the HarDDrive activity LED light.

If Windows starts to load, and you touch the Restart switch pins, the computer will restart over again, and Windows will load again.

(IF this computer has a Restart switch. I do NOT use one, even for the older computers. Just press CTRL, ALT, and DELete keys at the SAME TIME, to restart the computer, or use the Task Manager option)

One pin left all by itself? That is for 5 Volts, and only used by the factory. Leave it unconnected.

There may also be a blank spot on the Front Panel header, where it looks like a pin is missing. This is the KEY pin, and is not used.
It is just to orient where the other pins are.

Worried about getting shocked?
There may be a small spark, as you connect the wires, I will gramnt you that.
But the voltage is 5 VOLTS DC.
In comparison two D cell flashlight batteries produce 3 VOLTS DC.

The harmful AC voltage is contained in the metal enclosure, of the Power Supply. Can't get you unless you pour water on it close up, or stick a metal rod through one of the ventilation holes, in the Power Supply enclosure.

Regards,
joecoolvette

By the by. You could be a lot of people's hero, if you came back, and posted the pins for what they do. Post in a Comment.

Some products require time to turn on. These products might or might not give feedback in the form of blinking light(s). Wait a minute for the power light to turn on before proceeding to the solution.If your product does not respond when you try to print, press any button on the product to wake it from power save mode. Wait for the product to initialize, and then try to print again.
Try the following solutions in the order presented to resolve the issue. When one of the solutions resolves the issue, there is no need to continue troubleshooting.Solution one: Press and quickly release the Power button Press and quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button Figure 1: Press and quickly release the Power button If you press and hold the Power button too long, the product might turn on and then off without restarting. If this happens, press and quickly release the Power button ( ) again.If these steps resolved the issue , you do not need to continue troubleshooting.If the issue persists , continue to the next solution Solution two: Check the electrical connections and outlet Unplug the power cord from the electrical outlet, or the power strip or surge suppressor Carefully inspect the power cord for visible damage.If the power cord or power module shows any damage, contact HP to replace the power supply. Disconnect the power supply from the rear of the product.Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor.If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.Reconnect the power module to the product. Press and quickly release the Power button ( ) to turn the product on.If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn the product on.If the product turns on , the electrical outlet in the original room caused the issue.If the product still does not turn on , continue with the next solution.Solution three: Check the USB cable Disconnect the USB cable from the rear of the product.Figure 2: Disconnect the USB cable from the HP product Press the Power button ( ) to turn on the product.If the product turns on with the USB cable disconnected , replace the USB cable If the product still does not turn on , continue to the next solution.Solution four: Check the battery If your HP product has a battery, follow these steps:Check the battery light. If the light is red,recharge the battery.If the battery light is still red after recharge, replace the battery.Figure 3: Removing a battery (example only) 1 - Slide the battery release slider in the direction of the arrow 2 - Remove the battery Instructions for recharging and replacing a battery are available on the HP Web site.Solution five: Replace the power supply If you have completed all of the troubleshooting steps and are still experiencing a problem, contact HP to replace the power supply for your product Solution six: Service the product If you have completed all the preceding steps and are still experiencing a problem, service the product

Try the following solutions in the order presented to resolve the issue. When one of the solutions resolves the issue, there is no need to continue troubleshooting. 1) Press and quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button If you press and hold the Power button too long, the product might turn on and then off without restarting. If this happens, press and quickly release the Power button ( ) again.

• If these steps resolved the issue , you do not need to continue troubleshooting.
• If the issue persists , continue to the next solution.

2) Unplug the power cord from the electrical outlet, or the power strip or surge suppressor.

1. Carefully inspect the power cord for visible damage. If the power cord or power module shows any damage, contact HP to replace the power supply.
2. Disconnect the power supply from the rear of the product.
3. Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor. If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.
4. Reconnect the power module to the product.
5. Press and quickly release the Power button ( ) to turn the product on.
6. If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn the product on
7. If the product turns on , the electrical outlet in the original room caused the issue.

• If the product still does not turn on , continue with the next solution.

3) Disconnect the USB cable from the rear of the product

1. Press the Power button ( ) to turn on the product.
2. If the product turns on with the USB cable disconnected , replace the USB cable
3. If the product still does not turn on , continue to the next solution.

4) If your HP product has a battery, follow these steps:

1. Check the battery light. If the light is red, recharge the battery.
2. If the battery light is still red after recharge, replace the battery

5) If you have completed all of the troubleshooting steps and are still experiencing a problem, contact HP to replace the power supply for your product

6) If you have completed all the preceding steps and are still experiencing a problem, service the product

http://search.hp.com/query.html?charset=iso-8859-1&lk=1&la=en&nh=10&st=1&rf=0&qs=&tridion=0&hpvc=sitewide&uf=1&qt=Officejet+8500

Issue The HP product repeatedly turns off. Cause When low-power problems exist, the product might turn off repeatedly. Low power is a common problem in many home offices because of the number of electronic devices concentrated in one area. Solution one: Press and quickly release the Power button Follow these steps to turn on the product correctly.

1. Remove any memory cards or USB drives from the HP product.
2. Press, and then quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button . Figure 1: Press and quickly release the Power button

If you press and hold the Power button too long, the product might turn on and then turn off without restarting. The product might also appear to be turned off in Powersave mode. In either case, press, and then quickly release the Power button ( ) to turn on the product. Solution two: Check the electrical connections and outlet Follow these steps to make sure that all the power systems work correctly.

1. Unplug the power cord from the electrical outlet, or the power strip or surge suppressor. Power module Power cord NOTE: The power cord detaches from the power module. The term power supply refers to both the power module and the power cord.
2. Carefully inspect the power supply for visible damage. If the power cord or power module shows any damage, contact HP to replace the power supply.
3. Disconnect the power supply from the back of the product.
4. Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor. If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.
5. Reconnect the power supply to the product.
6. Press and quickly release the Power button ( ) to turn on the product.
7. If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn on the product.
   • If the product turns on , the electrical outlet in the original room caused the issue.
   • If the product still does not turn on , continue with the next solution.

Solution three: Make sure that other devices are not causing the issue Follow these steps to make sure that devices plugged into the HP product are not causing the problem

1. If the parallel and universal serial bus (USB) ports of the HP product have other devices plugged into them, unplug those devices.
2. Press the Power button ( ) to turn on the HP product.
3. Monitor the HP product to see if it turns off again.

• If these steps resolved the issue , there is no need to continue troubleshooting.
• If the issue persists , see the next step.

Solution four: Service the product If you have completed all the steps listed above and are still experiencing a problem, service the product.

Solution one: Press and quickly release the Power button Follow these steps to turn on the product correctly.

1. Remove any memory cards or USB drives from the HP product.
2. Press, and then quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button . Figure 1: Press and quickly release the Power button Illustration of pressing and releasing the power button

If you press and hold the Power button too long, the product might turn on and then turn off without restarting. The product might also appear to be turned off in Powersave mode. In either case, press, and then quickly release the Power button ( ) to turn on the product. Solution two: Check the electrical connections and outlet Follow these steps to make sure that all the power systems work correctly.

1. Unplug the power cord from the electrical outlet, or the power strip or surge suppressor. Power module Power cord Illustration: Power module Illustration: Power cord
   NOTE: The power cord detaches from the power module. The term power supply refers to both the power module and the power cord.
2. Carefully inspect the power supply for visible damage. If the power cord or power module shows any damage, contact HP to replace the power supply.
3. Disconnect the power supply from the back of the product.
4. Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor. If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.
5. Reconnect the power supply to the product.
6. Press and quickly release the Power button ( ) to turn on the product.
7. If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn on the product.
   • If the product turns on , the electrical outlet in the original room caused the issue.
   • If the product still does not turn on , continue with the next solution.

Solution three: Make sure that other devices are not causing the issue Follow these steps to make sure that devices plugged into the HP product are not causing the problem

1. If the parallel and universal serial bus (USB) ports of the HP product have other devices plugged into them, unplug those devices.
2. Press the Power button ( ) to turn on the HP product.
3. Monitor the HP product to see if it turns off again.

• If these steps resolved the issue , there is no need to continue troubleshooting.
• If the issue persists , see the next step.

Solution four: Service the product If you have completed all the steps listed above and are still experiencing a problem, service the product.

If you need more help come back.Post / thumbs / testimonial are welcome!

Indicator light is OFF.
Either dimmer stopped working or power to dimmer is off.
Check if electricity is present inside box.
Check nearby electrical plug to see if everything nearby has power.
Swap dimmer with regular switch and see if lights turn ON.
Check dimmer wires: if wires to dimmer are pushed into 'quick connect' holes on back of dimmer, these wires can get loose.
If dimmer is connected by wire nut, sometimes a wire can pull loose.
If no electricity is inside the box, and breaker is ON, then there is a loose wire inside one of the boxes on that circuit and electrician has to track back until loose wire is discovered.

Replacement parts for in-wall devices are not made.
If new dimmer is necessary, consider lighting factors:
Total wattage of lights. New dimmer has watt rating.
Type of lights. Dimmers specify florescent or tungsten (incandescent) or both.
Single-pole and 3-way. If two dimmers control same lights, one is control dimmer, other is companion dimmer.

Solution one: Press and quickly release the Power button Press and quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button . Figure 1: Press and quickly release the Power button If you press and hold the Power button too long, the product might turn on and then off without restarting. If this happens, press and quickly release the Power button ( ) again.

• If these steps resolved the issue , you do not need to continue troubleshooting.
• If the issue persists , continue to the next solution.

Solution two: Check the electrical connections and outlet

1. Unplug the power cord from the electrical outlet, or the power strip or surge suppressor. Power module Power cord
   NOTE: The power cord detaches from the power module. The term power supply refers to both the power module and the power cord.
2. Carefully inspect the power cord for visible damage. If the power cord or power module shows any damage, contact HP to replace the power supply.
3. Disconnect the power supply from the back of the product.
4. Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor. If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.
5. Reconnect the power module to the product.
6. Press and quickly release the Power button ( ) to turn the product on.
7. If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn on the product.
   • If the product turns on , the electrical outlet in the original room caused the issue.
   • If the product still does not turn on , continue with the next solution.

Solution three: Check the USB cable

1. Disconnect the USB cable from the back of the product. Figure 2: Disconnect the USB cable from the HP product
2. Press the Power button ( ) to turn on the product.
   • If the product turns on with the USB cable disconnected , replace the USB cable.
   • If the product still does not turn on , continue to the next solution.

Solution four: Check the batteryIf your HP product has a battery, follow these steps:

1. Check the battery light. If the light is red, recharge the battery.
2. If the battery light is still red after recharge, replace the battery. Figure 3: Removing a battery (example only) 1 - Slide the battery release slider in the direction of the arrow 2 - Remove the battery

Instructions for recharging and replacing a battery are available on the HP Web site. Solution five: Replace the power supplyIf you have completed all of the troubleshooting steps and are still experiencing a problem, contact HP to replace the power supply for your product. Solution six: Service the printer If you have completed all the steps listed above and are still experiencing a problem, service the product.

Hi
Disconnect the unit completely from the AC outlet for 5 or 10 minutes, then plug it back again.It will works.
Also I suspect it may be a loose power switch, or a problem with the power supply.
If it is a USB printer that derives power through the USB cable and not from a seperate power cable, then check the USB cable. That may be the source of the problem if the cable is bad.
Try the following solutions in the order presented to resolve the issue...

Solution one: Press and quickly release the Power button
Press and quickly release the Power button ( ) to start a Power On/Off cycle. Do not hold down the button .
Press and quickly release the Power button
If you press and hold the Power button too long, the product might turn on and then off without restarting. If this happens, press and quickly release the Power button ( ) again.
If these steps resolved the issue , you do not need to continue troubleshooting.
If the issue persists , continue to the next solution.
Solution two: Check the electrical connections and outlet
Unplug the power cord from the electrical outlet, or the power strip or surge suppressor.
NOTE: The power cord detaches from the power module. The term power supply refers to both the power module and the power cord.
Carefully inspect the power cord for visible damage.
If the power cord or power module shows any damage, contact HP to replace the power supply.
Disconnect the power supply from the back of the product.
Wait at least 30 seconds, and then plug the disconnected power supply into an electrical outlet. Do not use a power strip or surge suppressor.
If the green light (LED) on the power supply does not light up, contact HP to replace the power supply.
Reconnect the power module to the product.
Press and quickly release the Power button ( ) to turn the product on.
If the product still does not turn on, connect the product to an electrical outlet in another room, and then quickly press and release the Power button ( ) to turn on the product.
If the product turns on , the electrical outlet in the original room caused the issue.
If the product still does not turn on , continue with the next solution.
Solution three: Check the USB cable
Disconnect the USB cable from the back of the product.
http://h10025.www1.hp.com/ewfrf-JAVA/Doc/images/c01896072.gif( chek the figure)
Press the Power button ( ) to turn on the product.
If the product turns on with the USB cable disconnected , replace the USB cable.
If the product still does not turn on , continue to the next solution.
Solution four: Check the battery
If your HP product has a battery, follow these steps:
Check the battery light. If the light is red, recharge the battery.
If the battery light is still red after recharge, replace the battery.
http://h10025.www1.hp.com/ewfrf-JAVA/Doc/images/c01468528.jpg( chek the figure)
1 - Slide the battery release slider in the direction of the arrow
2 - Remove the battery
Instructions for recharging and replacing a battery are available on the HP Web site.
Solution five: Replace the power supply
If you have completed all of the troubleshooting steps and are still experiencing a problem, contact HP to replace the power supply for your product.
Solution six: Service the printer
If you have completed all the steps listed above and are still experiencing a problem, service the product.
Thanks for contacting fixya.com

A.Bad Power On switch. (Behind the Power On button)

B.Bad power supply

C.Power supply cables have come loose inside the computer.
1.Power supply to motherboard. (20-pin connector on motherboard)
This connector has two pins in it for Soft Power On. The power supply does not connect directly to the Power On switch. The power supply connects to the motherboard, and turns on via Soft Power On.

ADVISEMENT!!
ALWAYS have the computer unplugged from power before reaching inside!

ALWAYS work on a table. DO NOT work on a bed, or directly on a carpet floor. These are high areas for Static electricity! Static electricity will silently burn out computer hardware components. You may not see it or feel it.
Touch the metal frame of the computer case, to relieve your body of static, BEFORE you reach inside.