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Clicking noise, power and disk lights flicker after shut down


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#1
octal

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I have a custom built Pentium 4 system with an Asus P4P800 mother board. Presently running windows XP Professional. The system has been solid for years except for just recently. After doing a shut down the power, hard disk and card reader lights flicker. Also there is a noticeable clicking noise from the modem and speakers corresponding to the flickering lights. Sometimes power supply fan runs for awhile and the flickering lights gradually subside. Also the flickering lights will come back again later on there own, without doing anything to the computer. Sometimes after shut down the lights keep on flickering along with the clicking noise. The only way to shut it off is with power switch in back. I suspect either the mother board or the power supply. Any suggestions on what it could be?
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#2
Jack123

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01-Octal- Clicking sound on turn off-power & disc led flicker on( 1-13-2010)

Welcome to Geeks to Go –

I believe the some of Clicking Sound may also be your Hard Drive - - -powering On/Off - - -

There are several Motherboard Circuits that could have failures – but some of the components of theses circuits are not on the Motherboard ---
• [START/STOP] Switch –
• [RESTART] Switch ---
The wires may be compromised --- Switches are sort of dorky?? Mechanically Compromised??

Might want to physically inspect these components & wiring - -

Also might want to look at Motherboard for – Burnt /scorched areas – loose wiring from front panel switches – pinched/crimped wiring caught under motherboard or pinched fan wiring - -

Also there are 4 Similar Posts at the Bottom of your Post Page - - Scan thru them for ideas-
_________________________________________

If you have a Volt/Ohm Meter & feel comfortable using it – You can make some Measurements
At the 24 PIN POWER Connector – (Pin 8 – POWER OK) -- (Pin 9 - +5 STANDBY) -
PIN OUT --- http://pinouts.ru/Po...v2_pinout.shtml

Should be able to determine what is happening . . .. pretty safe

Also ---after shutting down - - -and you receive this OFF/ON condition . . .Try holding
PC Front Panel - [POWER SWITCH] – in for 4 -6 seconds & see if it can keep the Power OFF-
______________________________________________

The Power Supply could be the problem also-(as you mentioned)

When you shut the system down - - The Power Supply is still ON----It has Standby Power On ---
And has – [POWER OK] Signal waiting at The [START SWITCH] to Turn On the rest of the Power Supply –
Could be the – [Bleed-off Circuit] for the Large Capacitors are Open- keeping the Capacitors charged –

There are Power Supply Testers that you can purchase - - - to test it ???
But using a VOM & Pin Out http://pinouts.ru/Po...v2_pinout.shtml
& being observant - - -for physical damage ---- you should be able to discover problem
_____________________________________________

You also have some BIOS settings that you can have the Keyboard or Mouse to Turn PC ON-

Might want to check the - - -C-MOSS Battery - - -Might be low . . . That usually causes problem on TURN ON - - -

Also might want to check you’re your BIOS ACPI settings & Windows ACPI settings for conflicting settings ???
_____________________________________________

Just a few items to get you started
Jack123
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#3
octal

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Some of things I have already done: Vacuumed mother board inspected for damage, see none. Inspected wiring, checked connectors, switches don't feel flakey. Disconnected all external cabling from PC and checked PC on bench. When I turn off the power I have the clicking noise and lights blinking problem. Disconnected power connector to hard disk, still makes clicking noise. Pulled modem card, click noise gone but lights still flicker. Pulled all the PCI boards and graphic cards one at time , no help. You mentioned looking at the 24 pin connector pin 8 Power OK and pin 9 +5 Standby. I am not very familiar with these functions. What should I be measuring (results) with my volt meter?
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#4
Jack123

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02-Octal- Clicking sound on turn off-power & disc led flicker on( 1-14-2010)

You mentioned looking at the 24 pin connector pin 8 Power OK and pin 9 +5 Standby. I am not very familiar with these functions. What should I be measuring (results) with my volt meter?


First of all – I see that your Power Connector is a 20 Pin - - -not 24 Pin so you should use

http://pinouts.ru/Po...er_pinout.shtml
http://www.firingsqu...age.asp/1268/01

Pin 14 - Power Supply On (active low).
Low Signal (<1.0 VDC) switches power supply ON,
High Signal (>3.5 VDC) switches power supply OFF.

Pin 8 - Power Ok is a status signal generated by the power supply
to notify the computer that the DC operating voltages are within the ranges required for proper computer operation (+5 VDC when power is Ok) – CPU receives power – PC starts BIOS & Startup Routine begins
___________________________________________________

If you are not familiar with these signals & PC Start up sequence ---Then I do not feel that I should attempt to supply you with step by step measurement procedure - - - Too much room for error--- As you can see I already did not confirm your 20 pin power connector . . ..

I was just giving general statements/comments to get you pointed at a starting point - --

Your safest bet ---is to have your Power Supply Tested … Using a – PC Power Supply Tester …

But 1st - - Do you use a Protective Power Surge Power Strip for your PC? Maybe replace that ….
They only protect your Device ONE TIME- - - -then they usually cause other problems ??? after that –

Jack123

EDIT 1/14/2010---Jack123
Comments below -

Octal -
I am still interested in assisting you - - And will advise you with this problem - - -
I just have to put limitations . . . .

Jack123

Edited by Jack123, 14 January 2010 - 11:38 AM.

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#5
octal

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Jack123 - Note: All my troubleshooting was done prior to my first post and did not notice weather the PS connector was 20 or 24 pin. The computer is at a relatives house 25 miles away. I have repaired computers in the past with memory, PS and hard drive issues in the past. I have never seen a problem such as this one. I am Equipment Maintenance Technician in the Semiconductor industry so I feel comfortable with electronics. I am just not a PC Tech. I am trying to get just as much information together so when I make a trip to look at the PC, I can make the best of it and resolve the problem. I am grateful for any input you have on this issue.
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#6
Jack123

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03-Octal- Clicking sound on turn off-power & disc led flicker on( 1-16-2010)

I am Equipment Maintenance Technician in the Semiconductor industry so I feel comfortable with electronics


Ok- This is not your 1st Rodeo – Good--- That is good - -

Here are links for a - - -It is up to you whether you want to test it or not . ..
If it does a good test on Turning On/Off Supply then it would Fail or Eliminate the Power Supply.

• ATX Power Supply Tester http://www.tigerdire...e...&CatId=1107

• Power Supply Guide http://static.tigerd...pliesGuide.html

I do not know how well this tester – Tests the

• +5 VDC Standby PWR – PIN – 09
• POWER ON –PIN 14 (> +3.5 VDC = OFF) (< +0.25 VDC = ON)
• POWER OK – PIN 08 +5 VDC
__________________________________________________

Power Supply Research - -

The +5 VDC Stand By Section (Pin-09 = +5VDC OUT) & (Pin-14= Input) - - - Is the circuit in question-

Your symptoms - - LED Flashing – Fans Trying to Run – Modem Clicking etc. – indicates the Circuit may be breaking into Oscillations during Power Shutdown Procedure . . Which may be due to an open circuit …

I have an old Power Supply Schematic - - -It shows the Standby Power Supply section – It operates as soon as AC Power is connected to Power Supply – The +5V Standby Power is connected to(Power Plug – Pin-09). It also goes to Power (Plug Pin-14) thru a 4.7 K Ω Resistor – Labeled POWER ON {0V=RUN / +5V=STOP} ---

Pin-14 on the Motherboard goes to an I/O Connecter Header Strip on the Motherboard- - - Not directly but I could not trace it thru physically - - (Have No Motherboard Schematic) – but has to be connected –either thru a buffer circuit or a Voltage Divider??? This I/O Strip is connected thru a jumper to the – Front Panel POWER ON/OFF Switch ----- This switch applies a Momentary GND To this Signal POWER ON - -

What I am missing . . .Is How Windows is connected to this circuit to apply a ---Software Controlled 5 VDC Pulse to Turn the Power Supply Off - - -

I have searched the Internet - - -And I cannot find a decent description of the Shutdown Procedure. . .It just talks about Advanced Power Management Support - - but nothing concrete . . .

I have read where Microsoft has recently added an - - -Windows Update - - which may have changed the APM Power OFF Setting in - -Control Panel . . And possibly changed the BIOS Power Management Setting ?????
And be causing a conflict between these settings . . .???

(Typical Microsoft Update) . . . You did say - - -

The system has been solid for years except for just recently.



So it might be an Advanced Power Management Support Setting --- and/or BIOS Setting that was compromised by
A Windows Update . . .

1st Check BIOS Setting - - -Advanced Management Power

2nd Check Advanced Power Management Support Setting in Control Panel

• Click [Start]> [Control Panel]>[Performance and Maintenance] >[Power Options
• The Power Options Properties Property Sheet will open.
__________________________________________


Try the Power Management settings 1st - - -

Then try testing the power supply ---

You probably need to disconnect the supply - - Read the directions - - It appears that it is a GO/NO GO –type of test –

EDIT Jack123 ADDED This COMMENT ----(Anomalies to be aware of when Testing / working with Power Supplies)


- -Characteristic Anominalies with PC supplies –

They need a Minimum Load to turn ON - - The supply needs a load to regulate its output . . .

And you cannot Connect/disconnect thru a switch . . .

it needs to be connected to load - - And then Turn supply ON- - -

The Voltages need to be applied so they begin at O VDC and then ramp up to Nominal Voltage - - -

This Power Supply cannot regulate very well - --between (No Load – Full Load) or (Full Load – No Load)

Jack123

Edited by Jack123, 16 January 2010 - 03:43 PM.

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#7
octal

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Jack123 - I measured some of the voltages with PC turned off. The lights are flickering and the fans are turning. I presently have nothing connected to the computer. Measured pin 8 (PWR_OK)=.25V, pin 9 (5VSB)=4.7V and pin 14 (/PS_ON)= 5.1V. I believe this is OK for a PC that is suppose to be off. Well I found a neighbor that had a spare PS I could try. Problem is gone now. Put a brand new PS in, everything is fine now. Thanks for your help.

- Ken
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