Question about Compaq Presario SR2020NX Power Supply Replacement

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Flashing light on power supply

Computer not coming on

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  • Compaq Master
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Indicates bad Power Supply,






The Power Supply in your Compaq is an SMPS.
Switched-Mode Power Supply,

The cooling components are Heatsink's used inside, and a small internal fan.

The Heatsink's used in the above unit, are located in-between the letters A/B and C, plus C and D.
Aluminum block shaped finned areas, that are spaced apart, then connected to each other by a piece of metal.

The Heatsink's absorb heat from whatever they are placed against, and their thin fins then radiate the heat away.
Air flow from the small internal fan, helps carry heat away from the thin fins.

As the computer get's dirty inside, so does the Power Supply. It draws air Through the computer, and exhausts it out the back.
As the 'Gunk' covers the Heatsinks, and internal fan; the Power Supply overheats.

[Gunk = Dirt, dust, hair, carpet deodorizer, lint, name it ]

Heat = Wasted Energy

The Power Supply strains to keep up with the call for power, but eventually cannot, and fails.
Components inside fail.

The Power Supply converts 100 to 240 Volts AC, from your home, or business; into three low DC Voltages;
3.3 Volts
5 Volts
12 Volts

In comparison two D cell flashlight batteries store 3 Volts DC.

In your 24-pin ATX main power cable, there are Orange wires, Red wires, Yellow wires; and Black wires.

Orange wires are 3.3 Volts
Red wires are 5 Volts
Yellow wires are 12 Volts
Black wires are Ground wires (Negative. Same/same. This is a DC circuit)

[Note* For this connector, color of connector does NOT matter ]

DO NOT attempt repairing the Power Supply.
The Radial Aluminum Electrolytic Capacitors, that are in the Input Stage, and marked by the letter B; are HIGH voltage.
An Electrolytic Capacitor can keep it's charge for weeks, months, sometimes over a year.

Your fingers touch the terminals on the bottom; the charge could be released to YOU!
Your fingers complete a circuit, that one or more capacitors are in; the charge can be released to YOU!
Shock is BAD to FATAL!

Replace the Power Supply.

A) IF all of the LED's were on at once, they would use less than 1 Watt of power.
B) EACH fan uses 2 to 3 Watts of power.

C) A typical Processor can use 51 to 125 Watts of power.
Just depends on what Processor it is.
Specifications on HP Support, state it comes with an AMD Athlon 64 3500+ processor.
Reviews state it came out in 2006,

Believe it to be part number;
ADA3500IAA4CW (May 23,2006)

Uses up to 62 Watts

So you can see a Power Supply with a weak voltage rail, can light LED's, and maybe spin fans; but not have enough power to turn the Processor on, or keep it on.

Just thought you might like to know some of the stuff above.
Thought it would be better than, "Replace your power supply".

FOLLOW Anti-Static Precautions, BEFORE reaching inside your unplugged from power computer.

To make sure the Power Supply is your problem, before spending your hard earned money, you can test the voltages; or borrow a KNOWN to be good, compatible Power Supply, and use it for a temporary test unit.

Need guidance in replacing, or buying; post back in a Comment.

Posted on Jan 19, 2013


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Related Questions:

1 Answer

System health is critical. Red light flashing and system won't coming on

There is a critical system component hardware failure of some kind.
Front panel indicators:
1System power LEDGreen = Power on2Health LEDGreen = Normal3Power cap LEDGreen = Power cap configured4NIC 1 activity LEDGreen = Network link 5NIC 2 activity LEDGreen = Network link 6UID LEDBlue = Activated
Rear panel indicators:

1Power supply 2 LEDGreen = Power supply is on and functioning2UID LEDBlue = Activated3Power supply 1 LEDGreen = Power supply is on and functioning4iLO 2 link LEDGreen = Linked to network5iLO 2 activity LEDGreen or flashing = Network activity6NIC 2 link LEDGreen = Linked to network7NIC 2 activity LEDGreen or flashing = Network activity8NIC 1 link LEDGreen = Linked to network9NIC 1 activity LEDGreen or flashing = Network activity

Sep 09, 2013 | HP ProLiant ML370 G6 Server

1 Answer

Dell Inspiron 1721 will not power on,light on power supply flashes rapidly.

First, try and take out the battery and start the computer with just the power adapter. If the power adapter is still blinking, replace the power adapter. If the computer turns on with just the power adapter, replace the battery.

If the battery status light rapidly flashes amber, the battery may be defective. Purchase a replacement battery from Dell.

If the power supply status light flashes, the power supply may be defective. Purchase a replacement power supply.

Feb 15, 2011 | Dell Inspiron 1721 Notebook

1 Answer

The green light on the back is flashing, but when I push the power button nothing happens, any ideas what it could be?

The Green LED light flashing indicates a bad Power Supply. Weak voltage power rail.

Troubleshooting Power Supply Issues HP Pavilion A520n,

Click on > Power Supply light is on or flashes

"If the LED is still flashing (it should not flash with all connectors removed), plug the power cable into a different power outlet that is known to be good. If the LED still flashes, the power supply should be replaced."

The leading cause is the computer is dirty inside, to include the Power Supply
The next cause is that Electrolytic Capacitors have failed inside the Power Supply.

Solution is to replace the Power Supply.

The Power Supply used is the ATX form factor. The type of Power Supply used in over 80 percent of PC computers out there, and very readily available.

Size of the power supply case is approximately 6 inches Wide, 5-1/2 inches long (5.5), and 3-1/2 inches Tall. (3.5)

It is a 250, or 300 Watt generic unit, probably made by Bestec, Delta, or HiPro.

Scroll down to see the illustration and photo of the motherboard.

Power cables needed are;

A) 20-pin ATX main power cable,

{ ATX power supply's today come with a 20 + 4-pin ATX main power cable.
The power cable can be used as a 20-pin, or a 24-pin.

Add the 4-pin connector to make it a 24-pin, or do not use it, and have a 20-pin }

B) Enough standard 4-pin Peripheral power cables for the IDE (PATA) harddive, {1}, and the optical drive/s.

Today's power supply's come with either at least 4, or 6 of these power cables.

C) One Floppy Drive power cable.
Won't be used for a Floppy Disk Drive on your computer. It's power for the Memory Card Reader.

All of the above power cables are typical when purchasing an ATX power supply today.
Need guidance in choosing a Power Supply, please state in a Comment.


Nov 30, 2010 | HP Pavilion A520n (DW233A#ABA) PC Desktop

1 Answer

Flashing green light on power supplyonly fans come on at start up

just open ur pc case replace the ram and all connections for 5 to 10 min clean dust inside pc and also clean ram and put back in to pc and restart i hope ur comp will be right back to normal!

Aug 02, 2010 | HP (152769-001) (152769001) 250-Watt Power...

1 Answer

My monitor power light keeps flashing. It won't

usually this is a bad power supply. most electronic shops can repair them

Jan 10, 2010 | Acer AL1916W 19" LCD Monitor

1 Answer

Has green light that flashes 1 time when it's plugged in, then nothing comes on.

It might be the motherboard. Take the computer to your local computer repair shop and have them test the power supply and the motherboard. I hope this helps!

Jul 14, 2009 | Bestec (ATX100-5) (ATX1005B) Power Supply

2 Answers

When comp pluged in just a green flashing light

If you are sure that the 110 volt power is coming into the computer then the most likely problem is that th epower supply died. Obtain a new one of the same or larger wattagge as the one you are replacing . It does nto have to come from the manufacture of the computer. 

Nov 26, 2008 | Compaq Presario SR1000T (568657) PC...

5 Answers

Computer won't come on

I had the same problem, I unplugged my computer to move it before it had fully powered down. It wouldn’t start and all I got was the flashing lights.

I asked a friend who suggested I remove the power to the motherboard then reinsert it while it’s hot. Here’s what I did. Unplug the computer. Touch something metal so you’re grounded and don’t create a static shock on the motherboard. Now GENTLY pull the 16pin wire harness off the motherboard. Now plug the computer power cord back in. Then GENTLY plug the motherboard back in. With any luck the fan will start up and the computer will begin booting up. It seems to be some type of problem where the power supply doesn’t recognize the motherboard so it doesn’t do anything until it “sees it”? Probably some type of a safety to prevent motherboard burnout?

Oct 20, 2008 | HP Pavilion a705w PC Desktop

2 Answers

Power Green Light Flashing HP Desk Top PC m7250n

The 'cure' for this is to replace the power supply.
Inside your power supply are Electrolytic Capacitors. These are Filters for a power supply. To simplify detailing the construction of them, let's just say they are small aluminum 'cans', with an Electrolytic paste inside.

They are used to filter the incoming AC electricity from your house, (Business, school, whatever) They are also used to filter the DC electricity, coming out of the power supply. (Your computer power supply converts AC electricity, into DC electricity)

The one's we're going to concern ourselves with here, are the Output capacitors. The one's that filter raw DC into true DC.

When a capacitor (Of this type) starts failing, it's because Electrolytic paste is developing a gas inside. (Hydrogen gas) The gas expands, breaks a seal, and begins pushing the paste out. (Oozing out)
So much paste loss, and the capacitor can still function, but at a weakened state.

These capacitors deal with the voltage power rail for a power supply. Weak capacitor? Weak voltage rail!

Your processor requires a steady, 'clean', supply of DC voltage. It operates in a very TIGHT tolerance. Too much, or too little, it turns off. Too little it doesn't turn on.

The power surge has weakened Electrolytic Capacitors inside your power supply.
Lights light up. Fans spin. It sounds like the harddrive is running. (It IS! It's just sitting there spinning. More about that to come)

ALL the lights use less than 1 watt. EACH fan uses 2 to 3 Watts. The harddrive just sitting there spinning, uses about 5 Watts.

When it's time for the processor to turn on, (BIOS turns it on), it can't! Processors use 55 Watts to 125 Watts. Depends on the processor make and model.

Your harddrive just is just sitting there spinning, because the processor isn't running.

Solution? Replace the power supply, be happy.

Apr 02, 2008 | HP Media Center m1080n (PC099A#ABA) PC...

1 Answer

No power

No power or computer does not turn on. Additional information to why you may be recieving now power from the computer and/or why the computer is not turnning on.
Computer Power Supply Information Because of these precautions, no extensive information will be found on this page about opening power supplies.

No display on monitor. If no power light (green or orange light) is seen on the monitor display try pressing the power button until it comes on. If no light comes on after several

Good Luck/Please dont for get to Vote.Thank you.

Dec 15, 2007 | Acer Aspire 3002LCi Notebook

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