Question about Computers & Internet
Sorry, first time I have seen your query.
Restarting is bad Electrolytic Capacitors on the motherboard.
Radial Aluminum Electrolytic Capacitors to be more specific.
May require a bright light for visual inspection.
You're not only looking for the Vent Cover to be bulged up, or popped open, Jay; you are also looking for the Bung to be partially pushed out.
Bung is on the Bottom of the capacitor, so this means if the capacitor is bad, it may be on a hard lean.
What is happening, and why:
Let's start with the basic construction of an Electrolytic Capacitor.
The case is cylindrical in shape, and made of Aluminum. Looks like a miniature Coca-Cola can with the top, and bottom cut out.
The top is sealed with a Vent Cover.
Flat thin disk shaped aluminum 'lid', that has an X or lK etched partway into it.
The bottom is a flat disk also, but composed of synthetic rubber.
This is the BUNG.
2) Internal Components:
There are 3 strip layers inside;
A) One strip is an aluminum metal foil. It is the Conducting Strip.
Has the Positive lead connected to it. (Lead. Think stiff wire)
B) One strip is also made of metal, but has a non-conducting medium applied to it. It is the Non-Conducting Strip.
The Negative lead is attached to it.
Both the Positive and Negative leads poke through the Bung, at the bottom of the capacitor.
C) The last strip is composed of a paper-like material, and is soaked with Electrolytic Paste
The Electrolytic Paste soaked strip is laid in-between the two metal strips, and all three are rolled up tightly.
This is a basic explanation. There are Several of these layers inside an Electrolytic Capacitor.
When an Electrolytic Capacitor starts to go bad, the paste inside (Electrolytic Paste), develops a gas. Hydrogen Gas.
The gas expands inside the case of the capacitor.
When enough pressure has developed, the seals on the capacitot are compromised.
The Vent Cover etched shape breaks open, and/or one side of the Bung pushes out. (This makes the capacitor lean hard to one side)
The Electrolytic Paste begins to ooze out.
So much paste loss, and the capacitor operates in a weakened state.
TOO much paste loss, and the capacitor fails.
A Capacitor is designed to Slowly build up a charge, then release it all at once. This can be seen in some camera flash units, that use capacitors.
Crude explanation, is to imagine a large swimming pool being filled up with a garden hose, then one side of the pool is taken down all at once.
Capacitors are used as Filters, and Voltage Regulators.
The one's used as voltage regulators are in the Motherboard Voltage Regulator Circuit,
Part of what the motherboard voltage regulator circuit does, is to regulate voltage for the Processor.
The Processor (CPU) MUST have a steady, 'clean', supply of Voltage, and it MUST stay within the tight tolerance range for the Processor.
Cannot be too little voltage, or too much.
Processor doesn't receive the correct voltage it turns off. (BIOS turns it off)
Weak capacitor, or capacitors; will regulate the voltage, then break down, and Processor turns off.
Capacitor builds back up again the Processor turns back on.
Starts at 0:04
Bad capacitors can be replaced.
Now...........are all bad capacitors going to show visual signs of failure?
Sometimes the Electrolytic Paste dries up inside, and no visual outward signs of failure are shown.
HOWEVER..........due to the Capacitor Plague, and the fact I have done this repair on SEVERAL motherboards; it is MHO they can be replaced, and a good motherboard again is the result.
What really transpired, but is no longer talked about;
In a large capacitor company, in a large country; there was espionage.
A gentleman was fired from the company. In retribution a female co-worker decided to steal the companies Electrolytic Paste formula. A HIGHLY guarded secret.
She took the formula to a neighboring country, where they used the formula, and produced 1000's upon 1000's of capacitors.
(Looking back now it must have been millions)
Unknown to her the company had caught wind of what was going on, and before she grabbed the formula, they gave her a bogus formula instead.
The formula did not have the correct ingredients, to keep the Electrolytic Paste from developing gas.
These capacitors are STILL affecting us TODAY!
(From I believe the early 70's)
All electronic units that use Electrolytic Capacitors can be affected, not just personal computers.
This is why I believe there is a high rate, of replacing the bad capacitors, and the motherboard will work again.
Capacitors used on your motherboard are rated in Microfarads.
Symbol is uF.
Let's use a 470uf capacitor at 16 Volts, for an example,
Under the Capacitance heading, scroll down. Click on 470uF
Under the Voltage heading scroll down, click on 16 V.
Under the Termination style click on -> Radial
Leave all the other fields ALONE.
At the left side there is an -> Apply Filters, and there is one to the far right side also, under the chart.
Click on Apply Filters.
This is what you get,
Scroll down a little.
The only thing you are concerned with now, is the size of the capacitor.
Case Diameter, and Case Length.
If it states General Purpose Electrolytic Capacitors, don't sweat it.
They ARE computer grade, I assure you.
Need advice in de-soldering, and soldering? Just post back in a Comment. I'm your man.
For additional questions please post in a Comment.
Posted on Jan 26, 2013
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Posted on Jan 02, 2017
Oplen the cover ... physically install the device ... making SURE it is the proper type ... plug it in following the manufacturers instructions.
Posted on May 02, 2010
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