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How to discharge electrolytic capacitor for testing or replacement,POWER OFF procedure.

When the electronic or electrical circuit power is on,the whole system capacitors ,along with other parts consume electric power and become charged ,the higher value of capacitance grab more potential voltage, now if we need to test the capacitor with some meter or oscilloscope and need to remove it from the circuit board ,it become necessary to discharge them for the protection of sensitive test instrument and also for safety ,the procedure is very simple ,for this purpose we need one insulated bulb holder and place any filament type bulb in the bulb holder about 0 watt to 5 watts value,take two piece of thick insulated pieces of copper wire and solder the two ends to bulb holder and insulate them properly ,this procedure is for system POWER OFF test ,take out the power plug from the wall out let,and make sure power is completely OFF.
for discharging the capacitor we have to simply touch two ends of wire that came out from the bulb holder to the capacitor two terminal ,the potential in the capacitor will drain from positive to negative through the bulb filament resistance and discharge procedure will be completed,some time bulb will glow for short time some time it will not depending upon the current in the capacitor , now we can de solder or test the capacitor for replacement safely and securely.

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discharge a capacitor


Use a jumper wire with alligator clips on both ends. This may be dangerous if the voltage is very high and the capacitance is large say 1Mfd and a large spark is anticipated. If a circuit board I anticipate voltages less than 12 volts and you can hook one end of the alligator clip one side of the capacitor and the second alligator clip to the remaining terminal of the capacitor. Expect a spark to discharge when you short the capacitor.

Mar 25, 2012 | LG 42PC3D 42 in. Plasma Television

1 Answer

Computer does not want to stay on


Generally this means a bad Power Supply, or bad Electrolytic Capacitors on the motherboard.

I wish I knew what exact eMachines model number, you were referring to.
Because I do not, this solution will be generic.

Looking at the back of the computer tower where the power cord plugs in, this is the Power Supply.
(Rectangular in shape metal case, has it's own fan)

eMachines are a budget computer. Designed to save the consumer money, while trying to provide a medium design of personal computer.

However, in saving the consumer money, there are less than quality parts used.
The Power Supply is one of them.

(IF I had the model number from the back of the computer tower, next to the Windows product key, or up on the side of the tower, I could give you exact Power Supply replacement options, and guide you in replacing)

One of the main electronic components that break down in a Power Supply, are Electrolytic Capacitors.
They are the 'weakest link'.

The type of Power Supply used in a personal computer is an SMPS.
Switched-Mode Power Supply,

http://en.wikipedia.org/wiki/Switched-mode_power_supply

Click on the photo to the upper right.
The two round blue circles are Electrolytic Capacitors. This is a top view. The blue circle is the top edge of a plastic sleeve, which goes around the capacitor's body.

The letter E also points out more Electrolytic Capacitors.
Top view.
(The ones in B are Input Stage capacitors. They filter the incoming AC electricity. The ones marked by the letter E are Output Stage capacitors. They filter the outgoing DC electricity )

This is a side view of an Electrolytic Capacitor. (Radial Aluminum Electrolytic Capacitor, to be more exact),

http://en.wikipedia.org/wiki/File:Capacitors_electrolytic.jpg

The one at the bottom with the light blue sleeve, and 160V, and 10uf, on it. It is a Radial Aluminum Electrolytic Capacitor)

This is not an invite to replace these components. The preferred method is to replace the Power Supply.
(A good capacitor can hold a charge for weeks, months, sometimes over a year. The charge can be released to YOU, if the capacitors are not Properly discharged first)

Bad Electrolytic Capacitors on the motherboard. (Again, these are also Radial Aluminum Electrolytic Capacitors )

http://www.capacitorlab.com/visible-failures/index.htm

Part of what Electrolytic Capacitors do on the motherboard, (In referring to the motherboard's capacitors in your eMachines), is to regulate voltage.
This is the Motherboard Voltage Regulator Circuit.

Part of what the MVRC does, is to regulate voltage for the Processor.
The Processor MUST have a steady, clean, supply of voltage, and it MUST be within the voltage range for the Processor.

Can't be too much, or too little.

The capacitors that make up the part of the motherboard voltage regulator circuit, that handles voltage for the Processor, are in a Series circuit. Just like Christmas tree lights. If one capacitor goes bad, none of the rest will work.

http://www.hardwaresecrets.com/article/616

A short video (Not made by me) showing what happens when Electrolytic Capacitors are bad on the motherboard. (These 'caps' also are in the motherboard voltage regulator circuit, that handles the voltage for the Processor),

http://www.youtube.com/watch?v=KN6_-8fYHo0

(Starts at 0:04)

Replacing 'caps',

http://www.youtube.com/watch?v=YCSNWi3UHf4

http://www.youtube.com/watch?v=VaKobAKmYA4&feature=related

For additional questions please post in a Comment.

Regards,
joecoolvette


Dec 11, 2011 | E-Machines eMachines Desktop PC

2 Answers

I just put in a new battery and withina month it drained


something is draining the battery while the ignition switch is off. there are some things which remain on, but their drain is supposed to be very low. get an ammeter, which measures current, and remove the positive battery cable and place the ammeter between the battery post and the battery cable. there should be some very small amount of flow. now pull the fuses one by one while someone is watching the ammeter for you. eventually you will pull a fuse and the current drain will go down to almost nothing. that will be the fuse on which the offending circuit or doodad resides. now put the fuse back in and begin disabling each doodad until you hit the one which is causing the high current drain. typical things are autolocking mechanisms, lights which do not go off in trunks, under hoods, glove boxes.

Apr 09, 2010 | 1995 Mazda 929

1 Answer

Daewoo DVR-06 dead set


In CD players and in 99% of home electronics, power supplies are no longer being made with bulky iron "Transformers" but use a precision electronic circuit to replicate the transformer. This circuit uses a variety of transistors and other semi-conductors to accomplish this. Within this same "circuit" are capacitors which along with the other parts in the supply, must be within a precise tolerance for them to work.
In the quest to keep electronics marketable, some manufacturers have tried to cheapen their products with innovative ideas on how to make the same old parts and have failed miserably. One of the biggest failures in the industry has been the "capacitors" and the biggest failure has been within power supplies. THIS I BELIEVE is the problem you are experiencing as many many other electronics owners have also. One of the biggest outbreaks of these failing capacitors has been within the computer industry where "motherboards" have had to be replaced in great quantities.
The problem is fixable but in general, not worth the cost of repair and replacement is the obvious remedy. Sorry, I hope you haven't gotten to attached to your disc player as it has become a "Throw-Away" world unless you invest some bigger bucks in a better disc player. Good Luck!

Jan 31, 2008 | Daewoo DVR-06

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