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Have an Intel D845-WN motherboard that won't power up. If I short power connector pin 14 (green) to ground it powers up as long as shorted. Checked power switch at MB connector, when pushed, it closes, when released opens. Unit was working OK until I connected both signal and power to floppy. Disconnected floppy still doesn't power up. Removed MB from case looked for defects in traces, solder, etc. couldn't track the traces very far though, and same with DMM audio continuity tester.

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  • anonzero Sep 07, 2008

    Same problem - board powers on for ~ 1 second, then shuts dow & wont restart. Power sypply? CPU? or MB?

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2 Answers

I turn on my pc but 1 second it off what happen please sagest

Posted on May 12, 2008

I want intel d845 motherboard sw

Posted on May 04, 2008

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Start up light flashes once and it won't power on


Most probable cause is the power supply. Look at the back of the computer, check the voltage settings located near the power cord. This will be the small red tab indicating two different settings, If your in the US it should be set to 115. Also, the power supply should run the internal fan when it is turned on.

To test the power supply try this:

Open your computer case and locate the gray box that is the power supply unit. Trace the wires from the power supply to the boards and devices and disconnect all the cables by unplugging them.

Find the big connector plugged on the the motherboard, make sure it is disconnected and short the two pins: (GREEN & BLACK) Short green pin (14) to GND (any black) to switch power supply ON, disconnect green from GND to switch OFF.

This will switch the power supply, you should hear or see the fan in the power supply spin. If you do not see the fan spinning, and your sure you have shorted the correct wires, you have a faulty power supply. If you see the fan spinning, you can now test the voltage coming out of the power supply.

Place a volt meter on the following colors to test voltage:

The color code for the wires is: Red = +5V, Black = Ground (0V), White = -5V, Yellow = +12V, Blue = -12V, Orange = +3.3V, Purple = +5V Standby (not used), Gray = power is on (output), and Green = Turn DC on (input).

Feb 12, 2011 | HP Pavilion a6110n PC Desktop

2 Answers

The on-off button will not turn the computer on. I shut it off last night using the "shut down" software sequence, clicking two sequential "shut down" icons and waiting for the machine to power off. What...


Yeah I have seen switches fail a few times, its rare though, trace the wire back to your motherboard and disconnect the lead, then short the pins. If it comes on replace the switch, if it doesnt reset the bios via a the jumper and try again, disconnect the long ATX cable from the mother board and all power connectors from peripheral devices and on the Long ATX connector that was connected to the motherboard you will see a green wire, connect your mains to the power supply and short the green wire on the ATX connector with the black wire next to it, the power supply should fire up, if it doesnt try a new power lead and outlet, if it still does not fire up its your powersupply. If however you power supply does power up you should reconnect everything and try your power switch and shorting power switch pins on motherboard again, if the power supply does not come on then yor motherboard should be replaced.

Jun 22, 2010 | Dell Dimension 5100 (D51L1) PC Desktop

2 Answers

Faulty power supply or MOtherboard?


Test the Power Supply first.

If you have a multimeter, use the Positive (Red) probe lead to connect to the power wire to be checked.
The Negative (Black) lead connects to ANY ground wire. (ALL Black wires are Ground wires)

Three main voltages are produced by a personal computer Power Supply.
1) Orange insulated wires are 3.3 Volt
2) Red wires are 5 Volt
3) Yellow wires are 12 Volt.
(Again, ANY Black wire is a Ground wire)

Or use an economical power supply tester.
One example,

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=5250576&CatId=5471

You are making a connection from the green Soft Power On wire, to any Ground (Black) wire with that jumper wire.

Using an HP Pavilion A1330E desktop computer for an example,
we can see that the main power cable is a 24-pin ATX main power cable.

This is readily shown by looking at the motherboard,

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00496280&tmp_task=prodinfoCategory&lc=en&dlc=en&cc=us&lang=en&product=1829044

Scroll down to the motherboard illustration, and the motherboard photo underneath the illustration.

This is the pin-out for a 24-pin ATX main power cable, and connector,

http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24

The Green wire (Pin 16) is the Soft Power On wire. The other end of the jumper can touch ANY Black ground wire.

1) ALL the lights use less than 1 Watt of power.
2) EACH fan uses 2 to 3 Watts.
3) A typical Processor can use anywhere from 51 to 125 Watts. Depends on what Processor it is.

The three Processor options for the Pavilion A1330E are, (Socket 939 style),

A) AMD Athlon 64 X2 4800+
B) AMD Athlon 64 4000+
C) AMD Sempron 3200+

The Sempron 3200+ can use up to 62 Watts
Athlon 64 X2 4800+, 110 watts, and Athlon 64 4000+ can use up to 89 Watts.

Point?
You have nothing but the motherboard plugged in, and the Power Supply takes a 'nose dive'.
Power LED turns off.

Bad Electrolytic Capacitors in the Power Supply.
Replace power supply.

What causes this?
1) Most computer failure can be attributed to the inside of the computer is dirty, as well as the Power Supply.

When the cooling components of the Power Supply, (Fan, and internal Heatsinks), are clogged, the cooling capacity drops tremendously.

Heat = Wasted Energy

The Power Supply tries to keep up with the call for power, and eventually components inside the Power Supply fail.

A can of compressed air for computers, used on a regular basis as needed could prevent this. (Observe Anti-Static precautions Before placing hands inside computer)

2) Cheap quality power supply.
Saves the computer manufacturer money.

May 22, 2010 | HP Pavilion A1330E Customizable PC...

1 Answer

Green light next to power button stays on - no response from computer, totally frozen for up to 12 hrs, then green light goes off, computer suddenly comes on for 5-10 min then freezes again.


Good day sir, hi, You need a thorough check on your PC.
But first try testing the Motherboard, Processor and Memory module.

As this point you need a friend, that knows how to tinker with your PC

Or you may need to do this.

1. memory testing:
Try replacing a new memory ram module on your PC, get the modules out of the memory slot, and let it be tested on another PC. if good,

2. power supply
Test for the power supply box, remove the 20/24 pin power connector from the mainboard and short the green and any black wire, your fan should blow out air.

3. Test for motherboard.
remove all coonections from the motherboard, except the 20/24 pin power connector, and the 12v 4-pin molex power connector, connect the pc speaker or the thumb speaker on the speaker port, connect a keyboard, clear the CMOS, (or remove the battery temporarily), connect the header panel (power switch, reset, power led) place the processor and memory (the tested good one). power on.


You should hear a beep (good) The keyboard will light up the three leds, then a few seconds, the numlock led.

If you hear 1 long and 2 or 3 short beeps, problem with the display section. Reseat any graphics card. test again.

If you hear continous beeps, reseat the memory, if the beeping persist, replace your motherboard.

If you hear nothing? only fan blowing, replace your motherboard.

I can only give you instructions, you need a someone who knows how to service a PC.

Dec 17, 2009 | Compaq Presario 5000 PC Desktop

2 Answers

No power up. green led on broad is on and unit


If the connector is integrated in the motherboard, the entire motherboard needs to be replaced. You can check with some local tech shops to see if the connector unit can only be repaired

Jul 03, 2009 | PC Desktops

1 Answer

With power supply removed from chassis, how to get the supply on.


!! the signal you want to short is not the power supply good (pin 8, gray wire) but the power supply ON (green wire, pin 14) which needs to be grounded to turn on the PSU. (short pin 14 and pin 13 or 15)

hope this helps
Alex
www.CAS411.com

Mar 25, 2009 | E-Machines eMachines Desktop PC

1 Answer

Dell Dimension 8300 wouldn't start


Sounds like a power supply. You are getting the standby voltage and not the switched. plug all your wires in except the big 20 or 24 pin motherboard connector, take a small wire and short the green (PSU_ON) to black (ground) wires. This will simulate the computers "ON" signal. The fans should all spin up and your plugged in accessories should work, which means bad motherboard, if not bad power supply.

Mar 24, 2009 | Dell Dimension 8300 PC Desktop

1 Answer

Not sure about updated power supply


Gee. If HP recomends you not to hook up the extra four pins it must be because the four either go nowhere,which may cause a short or ground condition.Or that the extra pins will power something that will then  be in excess andd cause it too burn out. They know what will happen and for that rwason caution you not to do it. Of course it is you machine and  if you have extra money to replace things with go ahead and do it if you really want to know that badly.

Feb 20, 2009 | HP COMPAQ Presario SR5410F Pentium...

2 Answers

My computer won,t turn on


2x2 or 2x4 Power Connector Not Plugged In
If the power supply cable with the 2x2 connector or 2x4 connector (depending on your desktop board), is not plugged into the 12V processor core voltage connector located near the processor socket, the system will not boot up. You will see lights onboard and on the chassis front panel and the processor fan will spin, but nothing will appear on the monitor. See figures below for cable placement.
  • Make sure the fans on the processor are connected properly and running.
  • Make sure that the thermal interface material or the thermal grease is applied to the processor properly.
  • Make sure that the power supply fan is running properly and any other external case fans are running properly.
  • Make sure that the air intakes for the external fans are unobstructed and have at least several inches away from walls and other items.
  • Oct 08, 2008 | Gateway 3250S PC Desktop

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