power to Mb LED and ethernet port but no boot

[nickthequik13]

Hello,
I built my own custom desktop about a year ago. Has run perfectly! I come home the other day to notice my pc off, which is strange because it's always on. So I try to turn it back on. Press power button and nothing!.So I checked the surge protector etc. Everything is plugged in. I can see the green led on mobo lit up. Also I can see the Orange and yellow light on the Ethernet port on. But when I hit thepowrer button nothing happens. No fans turn on no bios beep. All I see is the red led from one of the fans blink for one second and that's it. Could this be a psu issue? Mobo issue? Dead battery for mobo? Any suggestions would be greatly appreciated!! Thanks

 

[Paul NZ]

Try replacing the CMOS battery, on the mobo it maybe flat. Then see if it turns on. If it does, reconfigure the BIOS settings

 

[westom]

Everything is plugged in. I can see the green led on mobo lit up. Also I can see the Orange and yellow light on the Ethernet port on. But when I hit thepowrer button nothing happens. No fans turn on no bios beep. All I see is the red led from one of the fans blink for one second and that's it.

Power is supplied by a 'system'. PSU is only one component of that 'system'. Power controller decides when a PSU power cycles and even when the CPU can execute.

Power controller may also have a safety lockout. This is reset by disconnecting a power cord for a few seconds. No static to discharge over many minutes.

If reseting a safety lockout does not restore operation, then two choices exist. First is to find a defect before fixing it or disconnecting anything. That means a digital meter, some requested instructions, and a minute of labor. The resulting three digit numbers then empower the fewer who really know how a power system works. Only then does the next reply provide a useful recommendation.

Second solution is shotgunning. Keep replacing good parts on speculation until something works. Most who use shotgunning first want to replace the PSU. And do not even know about a power controller.

Those are your only two options.

Meanwhile, connect an incandescent bulb to the same receptacle or power strip that powers the computer. If the bulb maintains more than 40% intensity, then AC power is sufficient;

 

[nickthequik13]

Try replacing the CMOS battery, on the mobo it maybe flat. Then see if it turns on. If it does, reconfigure the BIOS settings

So I replaced the cmos battery and still nothing. Any other suggestions??

 

[nickthequik13]

Everything is plugged in. I can see the green led on mobo lit up. Also I can see the Orange and yellow light on the Ethernet port on. But when I hit thepowrer button nothing happens. No fans turn on no bios beep. All I see is the red led from one of the fans blink for one second and that's it.

Power is supplied by a 'system'. PSU is only one component of that 'system'. Power controller decides when a PSU power cycles and even when the CPU can execute.

Power controller may also have a safety lockout. This is reset by disconnecting a power cord for a few seconds. No static to discharge over many minutes.

If reseting a safety lockout does not restore operation, then two choices exist. First is to find a defect before fixing it or disconnecting anything. That means a digital meter, some requested instructions, and a minute of labor. The resulting three digit numbers then empower the fewer who really know how a power system works. Only then does the next reply provide a useful recommendation.

Second solution is shotgunning. Keep replacing good parts on speculation until something works. Most who use shotgunning first want to replace the PSU. And do not even know about a power controller.

Those are your only two options.

Meanwhile, connect an incandescent bulb to the same receptacle or power strip that powers the computer. If the bulb maintains more than 40% intensity, then AC power is sufficient;

I have had the power supply unplugged for 3 days now, and have tried plugging back in to no avail. It does the same thing.. no case fans power on, no hard , drives spinning, no bios beep, psu fan does not even turn on. Literally the only action that happens is that the back case fan led light will flash for one second then turn off. Then It will not flash again when I press the power button until I unplug the psu and then plug it back in. Also I do not have an bulb in which to perform a test.

 

[nickthequik13]

So I disconnected my video card, and the computer powered up. So then I moved it to all the other pci-e slots, same thing is happening. So just trouble shooting and when I just plug in the 6 pin PCI connector into the video card, the computer boots up however the LED on my motherboard for VGA stays lit meaning an error for the car which is understandable since it doesn't have the other 6+2 pin connected. But whenever I plug in the separate 6+2 into the video card the computer will not boot. I even tried a new pci cable and chose a different slot coming from the psu, and still the same thing. So I don't believe it is my PSU.. I also connected an old video card that uses 2 6 pin connectors and it boots just fine and I get no error from the VGA LED on the mobo...

BTW I have an
ASUS m5A99fx Pro R2.0 MOBO
XFX ATI HD7870 GPU
AMD FX 8320
8GB Gskill sniper series 1866
Cooler Master V700 PSU

 

[westom]

So the video card is shorted or drawing too much current from one voltage. The power controller tells the PSU to power on, sees the problem, and then powers off. That is your LED flashing.

Is one (of many PSU voltages undersized or defective? Is the video card defective? Those are two possibilities that are confirmed or eliminated in minutes with a meter.

So again, either learn from a minute of labor. Or just shotgun; replace good parts until something works.

 

[nickthequik13]

unfortunately I do not have digital multimeter, If I were to go buy one, How would I check either the video card or the power supply?? I am not sure it is the power supply based on the fact that I plugged in an old video card with two 6 pin connectors and the computer ran fine. I could not verify picture on my screen though, My new monitor only has a VGA or 2 HDMI inputs and my old card only has DVI outputs.. But the fact it started up with with both power connectors makes me think it wouldnt be the PSU. Am I incorrect in thinking that??

Thanks for all the help!!!

 

[westom]

A meter is so ubiquitous as to be sold in Lowes, Home Depot, Radio Shack, Walmart, etc. Even Harbor Freight sells one for $5. Every auto mechanic must have one.

Nothing posted is tempered by numbers. A defective PSU can still boot and run some computers. A perfectly good PSU can fail in some computers. The reasons why (ie numbers from a meter) are your only means to a useful answer.

I don't have time now to post requested instructions. Those will probably be posted tomorrow. The only other thing you need is minutes of time for the labor and to post the resulting numbers.

 

[westom]

How would I check either the video card or the power supply??

Restore everything as when the computer worked. AC power cord connected to a receptacle. Computer not on. Set a digital meter to 20 VDC. Attach its black probe to the chassis.

Locate a purple wire (pin 9) from the PSU to where it attaches to the motherboard. Use a red probe to touch that wire inside a nylon connector that attaches to motherboard. If necessary, make that connection using a needle or paper clip. It should read somewhere around 5 volts. Record that number to three digits.

Next, do same with a green wire (pin 16). Then press computer's Power On button. Monitor how meter changes and what it eventually settles to. First number should be something well above 2.6. Second number should be something near to zero, Actual numbers and time to change (behavior) are relevant.

Repeat same to a gray wire (pin 8). Note a higher starting voltage, a lower final voltage, and its behavior. Report those three digit numbers and behavior.

Setup computer to execute as much software as possible. IOW it should be outputting sound loudly, while searching the disk, while playing complex graphics (ie a move), while powering a USB device, while accessing the internet, etc. Having it access many peripherals simultaneously is important. If it cannot power up, then monitor any one red (pin 4,21-23), orange (pin 1,2,12 or 13), and yellow (pin 10 or 11) wire for what each does as and after its power button is pressed.

Report all measurements for six wires to three digits. Next reply will identify or exonerate suspects.

Repeat this both with the suspect video controller and with the other controller. Numbers from the above procedure for both setups will provide even more useful information.

BTW, if wires are not colored, then a PSU may not be ATX Standard. See www.smpspowersupply.com for color and pinouts.