carmanz1gal, and olik2,
Power won't stay on - Bad Power Supply
Computer restarts - Bad Motherboard
[olik2,
Bad Motherboard:
Electrolytic capacitors used in the motherboard Voltage Regulator Circuit, are failing, or have failed, is the general cause of motherboard failure.
Part of what the motherboard Voltage Regulator Circuit does, is to regulate Voltage for the Processor.
A Processor must have a Steady, 'Clean', supply of Voltage, and it must be within a VERY tight tolerance range.
Electrolytic Capacitor failure, also applies to the Power Supply 'tip' you read.
When the 20/24-pin ATX main power cable is plugged into the motherboard, it supplies power to the Motherboard, Processor, Ram Memory, optical drives, cooling fans, and a graphics card, if used.
(Provided the graphics card does not require additional power, from the power supply, via an attached power cable)
1) ALL the LED lights use less than 1 Watt of power
2) EACH fan uses 2 to 3 Watts
3) A typical Processor can use up to 51 to 125 Watts.
Depends on what Processor it is.
Unplug the 20/24-pin ATX main power cable, and the failing Electrolytic Capacitors in the Power Supply, have a chance to build up a full charge again.
[A capacitor slowly builds up a charge, then releases it all at once.
Think of a capacitor as a large swimming pool, being slowly filled up by a garden hose. Then one wall of the pool is taken down all at once ]
Plug the 20/24-pin ATX main power cable back in, and the stored charge is enough to turn the Processor on, and keep it running.
It's all due to the Electrolytic paste's chemical composition, and amount, at the time.
Electrolytic Capacitors used in the Power Supply, and on the motherboard, are essentially small aluminum 'cans', with electrolytic paste inside.
There are three strips inside the 'can' case.
1) One is a metal strip, and is thin aluminum foil. The Positive lead is connected to it.
It is the Conducting strip.
2) One lead is also a thin aluminum foil, and has a non-conducting medium applied to it.
It is the Non-Conducting strip, and has the Negative lead attached to it.
3) The last strip is composed of a paper-like substance, and is soaked with Electrolytic paste.
The Electrolytic paste soaked strip, is placed in-between the two metal strips, and all three strips are rolled up tightly, then placed in the aluminum can case.
At the top of the aluminum can case is a flat, thin aluminum disk.
The disk has a shape etched part way into it.
The shape is usually a K or X.
At the bottom of the can case where the Positive, and Negative lead protrude, there is another seal.
It is called a Bung.
The Bung is a round, flat synthetic rubber disk.
The Negative, and Positive lead protrude through it.
(The above is a description of a Radial Aluminum Electrolytic Capacitor)
When an Electrolytic Capacitor starts to fail, there is a gas developed inside the case. (Hydrogen Gas)
The gas expands, and pushes against the case, and the upper, and lower seals.
The top seal X or K will break open with enough pressure, and this action allows the Electrolytic paste to be pushed out.
(Oozes out)
The bottom Bung seal can also be compromised. One side of the rubber-like disk, will push out of the bottom of the can case.
This too allows the Electrolytic paste to be pushed out.
So much paste loss, and the capacitor will operate at a weakened state.
Too much paste loss, and the capacitor will fail ]
carmanz1gal,
You have a bad Power Supply.
Weak Voltage power rail.
Causes of Power Supply failure:
1) Most of the time due to the inside of the computer is dirty, as well as the inside of the Power Supply.
Computer unplugged from power, computer case open, a can of compressed air for computers used on a regular basis as needed, could prevent this problem.
A computer that is dirty inside is a Very common thing.
If one does not know how to open the computer case, or use the correct procedures, it may seem a daunting task.
To have a computer tech do the procedure cost bucks.
2) There are outside sources that can also add to the detriment of a Power Supply.
Power surges from the power utility company, brownouts, and the power utility company does not always supply THE correct voltage.
Example:
In the US, the common Voltage used is 120 Volts. The utility company is only required to keep the voltage between 108 to 127 Volts.
However the transformer on the utility pole outside your home, that feeds electricity to your home, may be stepped up too far.
I have had instances, where I had to call the utility company to have a lineman, turn the voltage down on the stepdown transformer to my home.
It was at 135 Volts!~
(If you have lightbulbs that seem to not last very long, you may want to have a licensed electrician, check the AC voltage amount coming into your home)
3) Lifecycle:
A computer Power Supply's usage is rated in hours.
So many hours of usage is it's Lifecycle.
Your Power Supply may be at the end of it's Lifecycle.
What HP Compaq d330 computer is it?
http://h20180.www2.hp.com/apps/Lookup?h_lang=en&h_cc=us&cc=us&h_page=hpcom&lang=en&h_client=S-A-R163-1&h_query=HP+Compaq+Desktop+D330&submit.x=9&submit.y=4