Question about Motherboards

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I get no output from an LC-350 ATX BIAS SUPPLY

When I hit the power switch on the computer the systems fan twiches about 45 degrees and stops. I do not have a schematic diagram for this unit. How can I get one, and what should I be looking at ??
The wires are all color coded and feed into a 20 pin connector.
The mother board is P4VMM2. No leds light up at all when the power switch is operated, but the fan motor always twiches once, upon operation.
Thanks Tibor

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  • Celenous May 11, 2010

    This could be so many things. Please provide more information. What were you doing when you first experienced the problem? What is your memory configuration? What type of memory are you using? Did you mix DDR and SDRAM? Have you verified that the fan is working correctly? It might not be the power supply but the motherboard itself or one of the components in it. Here is a link to the manual for the motherboard.
    http://www.ecs.com.tw/ECSWebSite/Downloa...
    Send me the specs of your system and we can work out what the issue is.

    Cheers,
    Celenous


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DOES THE SWITCH HAVE 4 REMOVABLE CONNECTION, IF SO THE POWER SUPPLY MAYBE HOOKED UP WRONG, REMOVE ALL WIRES AND CONNECTION FROM THE MOTHERBOARD LEAVE ONLY THE POWER CONNECTION AND THE VEDIO MONITOR CABLE, ADD ONE CONNECTION AT A TIME AND TURN SYSTEM OFF AND ON UNTIL YOU HAVE A PROBLEM AND I KNOW IT IS ALOT OF WORK THAT WHY YOU PAY SO MUCH FOR A COMPUTER EXPERT TO LOOK AT YOU COMPUTER DESKTOP OR LABTOP.

CANDYMANGANDY

Posted on Jan 27, 2009

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My motherboard is getting power from a 450w smps coz the board LED gets on when I switch on the ups. But pressing the power button on the cabinet does not switch on the system. Please help!!!!


From your diagnoses you may have a bad Power On switch, or a bad Power Supply.

Reasoning?

An ATX power on switch is connected to the motherboard's Front Panel header.
From there the circuit is continued through the ATX main power cable, and into the Power Supply.

The Power On switch connects the Soft Power On wire, to Ground.
(The Soft Power On wire is abbreviated as PS_ON. The wire is Green)


If the Power On switch is bad the Power Supply will not turn on.


A bad Power Supply will have a weak voltage power rail, (Or more than one)
Enough power to light LED lights, and perhaps spin fans, but not enough power to turn the Processor on.
No Processor operating, no computer.

1) If all of the LED lights were on at once, they would use less than 1 Watt of power.

2) EACH fan uses 2 to 3 Watts.

3) A typical Processor can use from 51 to 125 Watts. Depends on what Processor it is.
(Older Intel Pentium III's, and comparative AMD processors used less than 51 Watts)

You may have enough power to light that LED light, but not enough to spin fans, or turn the Processor on.


There is a simple test to see if the problem is the Power On switch, or the Power Supply.
Bypass the Power On switch.

A jumper wire is used to temporarily connect the Soft Power On wire to ANY Ground wire.
The connection is made at the Back of the ATX main power cable's connector, with the ATX main power cable plugged into the motherboard, and computer plugged into power.

1) The Asus M2N-MX (And SE version) motherboard uses a 24-pin ATX main power cable.

http://www.asus.com/Motherboards/AMD_AM2/M2NMX_SE_Plus/

This is one example of a 24-pin ATX main power cable, and it's respective connector on the motherboard,

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

Looking at the photo to the far right, shows the 24-pin ATX main power cable plugged into the motherboard.
This is the position for the test.
(Computer also plugged into power)

The BACK of the connector is where the wires go into the connector.
The jumper wire is used on the Back side of the connector.

One end of the jumper wire goes down into the socket hole with the Green wire.
(Soft Power On wire)
The other end of the jumper wire goes down into ANY socket hole with a Black wire in it.
ALL Black wires are Ground wires.

The jumper wire goes down into the socket hole RIGHT NEXT TO the existing wire.
The jumper wire MUST go down into the socket hole far enough to touch a metal terminal.

At the end of every wire going down into the ATX main power cable's connector, is a metal terminal.
The metal terminal is pretty far down in the socket hole.

The preferred jumper wire used is a paper clip.
The paper clip's diameter is small enough, to go right next to the existing wire in the socket hole, and touch the metal terminal.

The paper clip is straightened out, then bent into a U-shape.
The 'legs' of the U-shape go down into the two socket holes.
The middle is wrapped with a few wraps of black plastic electrical tape.
The taped area is for your finger, and thumb to hold onto.

The voltage is 5 Volts DC.
Two D cell flashlight batteries produce 3 Volts DC.
There may be a small spark when you make the connection, advising you in advance.

The connection made is no longer than 2 seconds.
(The Power On switch is a Momentary Contact Switch)

Computer comes on, (Power Supply actually) you know you have a bad Power On switch.
Computer does Not come on, you know you have a bad Power Supply.

For additional questions please post in a Comment.
Regards,
joecoolvette

Jul 10, 2011 | ASUS M2N-MX Motherboard

1 Answer

Computer wont start after pressing the power switch.. the processor fan stops together with the power supply...what will i do...i already check the power supply, memory and the different cables inside the...


check *********** board if there are some capacitors that are deformed, busted parts may do the problem , try first to pull out socket,connections then place it back again 2-3 time to avoid corrosion.

Jul 07, 2011 | DFI NF3 250-AL NVIDIA Socket 754 ATX...

1 Answer

Hp palilivon a 1100y lost all power will not come back on i checked all cords power source everything seems to be ok. but no power still?


I'm going to base this solution on two scenarios from the info you have posted.

1) The power to your home/business went out. Now it's back on.

2) The power has been on all along, and the computer quit.


Based on 1) above;

The Power On switch could be bad, or the Power Supply.

A voltage spike could have occurred, and taken out the ATX power on switch.
(A generic ATX Power On switch is around $5. Example,

http://www.axiontech.com/prdt.php?item=78201 )

A voltage spike could have taken out a power supply that is of low quality, and/or on it's last leg.

The power supply used in an HP Pavilion a1100y desktop computer is of low quality.
Low quality components are used inside.
(Bestec, and Delta are two of the low quality power supply's used by HP in this time frame)

Plus add to the fact that the computer has some age on it, (5 years old?), and could be dirty inside.
Dirt,dust, etc. 'kills' computers and power supply's.

There is a simple test to perform to see whether the problem is the Power Supply, or the Power On switch.
(The Power On switch is located within the plastic Power On button assembly)
If you wish to know how to perform this test please post in a Comment.
(Free)


Based on 2) above;
The Power Supply is bad.
The test would be either to use a multimeter, and check the three main voltages coming out of the Power Supply,
Or,
Substitute the power supply with a KNOWN to be good compatible unit.
(250 to 300 Watt)

(Sometimes access to another known to be good, compatible power supply may be obtained from a computer that is no longer in use. The user has upgraded to a better computer.
Compatible being that the Power Supply has the required Wattage, and required power cables)

[The three main voltages produced by an SMPS (Switched-Mode Power Supply) used by the Pavilion a1100y desktop computer are;

A) 3.3 Volts DC (Orange wire)
B) 5 Volts DC (Red wire)
C) 12 Volts DC (Yellow wire)
In comparison two D cell flashlight batteries produce 3 Volts DC ]

This is HP Support>Pavilion a1100y desktop computer> Motherboard Specifications,

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00499325&tmp_task=prodinfoCategory&lc=en&dlc=en&cc=us&site=null&lang=en&key=null&product=1118244

Looking at the motherboard illustration, and photo at the bottom of the page, we can see what power cables are needed for the motherboard;

A) 24-pin ATX main power cable
(Connector on motherboard illustration marked as ATXPWER1. In the photo it is whitish, and has two vertical columns of 12 square socket holes. It is to the Right of the Ram Memory slots)

B) 4-pin ATX main power cable.
(Connector on motherboard illustration is marked ATX12V. It is to the left of the Intel Northbridge chipset - Intel 915GV GMCH.
In the photo it is the whitish square connector with four square socket holes. It is to the Left of the
aluminum finned Heatsink, sitting on top of the Intel Northbridge chipset)

Other power cables needed are;
1) A SATA power cable for the SATA harddrive
2) One or two 4-pin Peripheral (Standard) power cables for the optical drive/s. (CD/DVD drives)

The Processor fan cable attaches to the motherboard. (CPU_FAN)
The computer case fan attaches to the motherboard. (SYS_FAN)

The ATX form factor is used primarily for describing a motherboard.
Form Factor denotes the size, and shape, and power cables for a Power Supply.

The ATX form factor for a Power Supply;
Size: Approximately 6 inches Wide, 5-1/2 inches Long, and 3-1/2 inches Tall.

A $40 ATX power supply with 300 Watts will do just fine. No need to buy an expensive Power Supply based on advertising as a direct substitute.

One example of an inexpensive reliable ATX power supply for a Pavilion a1100y desktop computer,

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1389575&CatId=1078

Has all the power cables you'll need. Actual maximum wattage rating is 350 Watts.
Information,

http://www.hardwaresecrets.com/article/332

For additional questions or to clarify anything I have stated, please post in a Comment.

Regards,
joecoolvette

Jun 21, 2011 | Motherboards

1 Answer

Is it safe to plug my computer with an ATX 350 power pack into USA power supply?


look at the rear of the power source , there should be a voltage slider switch - put it in the 120v position.
If there is no switch then you will need a new source, one that has it.

Nov 29, 2010 | Motherboards

1 Answer

P4P800 MB will not power up. Power switch only yields flashing lights. Turn off and wait and repeat yields same result. Disconnect power from all drives = same result.


You'll need to check the voltage output of your current power supply. The ATXPWR1 connector. See page 2-29 in your manual.
You will need a volt meater to check the power out-put for each.
The link provided should help you test your power supply; http://www.compute-aid.com/atxspec.html
If you feel this is a bit too difficult you can swap out your current ATX power supply with another. The power supply for the Asus MB should support a minimal of 300Watts output. Its recommended to use a 350 to 400Watt PS. Please provide what LED light is flashing and what color it is. Also include any beeps you may hear during boot up of the system. (Long, short and repeating if any). You can send me an email at triptic12@yahoo.com

Cheers
Mike

Nov 23, 2009 | ASUS P4P800 SE (890552603657) Motherboard

2 Answers

System won't turn on but when i pushg down on one side of the power suply connectore the fan starts running but computer stioll won't turn on it used to boot up then opne day stopped


It sounds like you have a faulty connector - I would return the item under warranty. Otherwise, if it is out of warranty, you will have to source a new motherboard.

Nov 23, 2009 | ASUS COMPUTER INTL P5SD2-VM MBD MATX LGA...

2 Answers

Asus K8V SE Deluxe - will not turn on


it should have pins to reset it touch the two reset pins with screwe driver to activate it if still gont work you have a bios problem

Dec 05, 2008 | ASUS K8V-MX Motherboard

2 Answers

Intel D865PERLL Motherboard will not power up


Hi nkda2000, this is as close as I could find for power schematics. Intel D865PERL
http://support.intel.com/support/motherboards/desktop/D865PERL/sb/CS-027143.htm

(There is no Intel D865PERLL board). Sure it's a typo. Have done searches for D865PERLL & found it (Not on Intle's web site) but when looking at the specs it's listed as D865PERL. (One L ) not two.

I hope the Technical Product Specification pdf can help you check the power on the motherboard.

Luck!

Mike

May 07, 2008 | Intel D865PERLL Motherboard

2 Answers

Wont boot.


normally this happens if your MB sensor circuitry is not detecting the correct speed of your fan or the correct temp of your system and proc. Try to Load the default settings of your bios and test again. if still having same problem what I suggest is check the 12volts output and 5 volts output of your PSU. To check it you need a Multimeter set to DC volts and put the negative probe to the black wire in a standard PSU plug and the red probe to the yellow cable (for 12v) and for the 5 volts just transfer the red probe to the red cable. If you have the correct voltage output, you have to hot wire your Proc Fan to get DC supply directly from your PSU. Your Proc Fan normally runs using 12volts DC.

Hope this helps.

Apr 29, 2008 | Intel D865GVHZ Motherboard

2 Answers

Motherboard fried?


the problem is your power supply, since the power supply have differrent output voltage there is 12volts, 3volts and so on. the 12volts output voltage is not giving enough power. you can determine this by detaching the 20pins from your motherboard coming from the power supply then power-on the power supply then use a jumper wire insulated but scraped both ends (conductor visible) then connect it to the green connector and the grey connector if the fan of the power supply doen't rotate then you 12volts output voltage is busted.

Oct 22, 2007 | EliteGroup 915P-A Motherboard

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