20 Most Recent E-Machines Bestec ATX-300-12E Rev. D 300w E-Machine GTW Power Supply Part 100929 (ATX30012E) Power Supply Questions & Answers

check the power outlet, try swapping power cord with the monitor power cable. if still no power, try disconnecting power to motherboard cd rom. leave the hdd connected and see if the power supply fan come on. if not the you have a blown power supply.

E-Machines... • Answered on Apr 20, 2012

Test your PSU or replace it if your power supply units fan is not working your PSU is faulty

One bad lead can cause a computer to continue on a cycle or to shutdown or fail to detect/ boot up a computer hard drive

Test all leads that attach to your hard drive including electrical extensions,IDE,SATA

the leads from your "((motherboard to your hard drive))" make sure they have a secure connection and are not faulty or just replace them they could be faulty make sure all leads that are attached to your drives dvd\cd 3 1/2 inch floppy have secure connections and are not faulty even the electrical extensions or just replace them they could be faulty a computer needs its connections to continue its cycle and have an end so any faulty leads will end up with a computer error hope this helps

E-Machines... • Answered on May 10, 2011

eMachines uses low quality hardware components inside their computers. This is the way they can sell them at budget prices.

One main hardware component is the low quality power supply they use.
A generic power supply made by Bestec. (A generic power supply manufacturer)

(PSU. Power Supply Unit. The type of PSU used is a SMPS.
Switched-Mode Power Supply,

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

Low quality;
A) Electrolytic Capacitors (Radial Aluminum Electrolytic Capacitor)
B) Rectifier Bridge
D) Wiring is too small in gauge
to name a few of the components.

However IMHO it is also best to check out the Power On switch.
There is a simple test to see whether the problem is a faulty Power On switch, or a faulty Power Supply.

The test involves bypassing the Power On switch. The Power On switch is not involved in this test.
A jumper wire is used on the Soft Power On wire, [ PS-ON ], and a Ground wire in the ATX main power cable connector.

If you bypass, and the Power Supply comes on you have a bad Power On switch.
If the Power Supply does Not come on you have a bad Power Supply.
If you would like to know more in detail on how to perform this simple test, simply post so in a Comment.

The Power Supply used is just a common ATX version.
ATX refers to the Form Factor of the power supply.
Regular size ATX form factor is approximately 6 inches Wide, 5-1/2 inches Long, and 3-1/2 inches Tall. (Height)

There are also differences in the pinout of the ATX main power cable.
Yours may have 20-pins, or 24-pins.
Power Supply's sold now take this into consideration.
Their ATX main power cable can be used as a 20-pin, or a 24-pin version.

[ General example of a 20-pin ATX main power cable, and it's connector,


Example of a 24-pin ATX main power cable, and it's connector,


Your motherboard may also require an additional power cable, commonly referred to as a P4 power cable, or P4 ATX 12V power cable, or just ATX 12V.
The actual name is 4-pin ATX +12 Volt power cable,


If you would like help in finding an inexpensive reliable Power Supply, please post in a Comment.
I will need to know what Model Number of eMachine you have. It's on the back next to the Windows product key, or up on the side of the computer tower.

If you need anything explained that I have stated here, please let me know in a Comment.

E-Machines... • Answered on Apr 21, 2011

If you know the receptacles that you have plugged the computer into, indeed have power, I would suggest you diagnose the Power On switch, and the Power Supply.

See of the problem is the Power On switch, or the Power Supply.

A jumper wire is used on the main ATX power cable.

1) If the Power Supply comes on you have a bad Power On switch.
2) If the Power Supply does Not come on, you have a bad Power Supply.

Your problem is posted in the eMachines Bestec ATX-300-12E power supply section.
Going with that we are discussing a Bestec ATX 300 watt power supply, the main ATX power cable is a 20-pin ATX main power cable.

Typical pinout of a 20-pin ATX main power cable,


Note the Green wire in the BACK of the connector, in the photo to the far right.
This is the Soft Power On wire, or also abbreviated as the PS_ON wire.

Note the Black wires. ANY Black wire is a Ground wire.

With the 20-pin ATX power cable plugged into the motherboard, as shown in the photo, a jumper wire is touched to the Green wire, and to ANY Black wire.
The computer (Power Supply) is also plugged into power.

Generally a paper clip is used for the jumper wire.
The paper clip is straightened out, then bent into a U shape.
Black plastic electrical tape is then wound around the middle of the U shape.
This taped area is for your fingers, and thumb to hold onto.

The 'legs' of the paper clip, are then inserted down into the socket holes, in the back of the 20-pin ATX main power cable's connector.

Down into a socket hole with the Green wire, and also into a socket hole with ANY Black wire.
The 'leg' of the paper clip goes down into the socket hole, RIGHT NEXT to the existing wire.

At the end of every wire in the 20-pin ATX main power cable, is a metal terminal end.
The metal terminal end is pretty far down in the socket.
You must ensure that the metal end of the paper clip, touches the metal terminal.

The voltage is 5 Volts DC.
Two D cell flashlight batteries produce 3 Volts DC.
There may be a small spark as you make the connection.

Warning you in advance.
You can see the voltage is VERY low, however.

I would like you to perform this test, then post back in a Comment as to your findings.


E-Machines... • Answered on Apr 04, 2011

You can check if the power supply is bad using a multitester.

Connect the power cord at the back of the power supply and plug it in an AC outlet. Measure the voltage out from the connector. Using the multitester (set it to DC range), insert the black probe to one of the black wire in the peripheral connector of the power supply while the red probe in the yellow wire. Reading should be +12VD. Now, transfer the red probe to the red wire, reading is +5VDC. Reading below this measurement is a clear indication of a bad power supply.
Put some load in it, like connecting a hard drive or a cd rom drive.Try measuring the output voltage again. If voltage out dropped then it is Bad.

Hope this will help you understand.
Thank you for using Fixya.

E-Machines... • Answered on Feb 06, 2011

power supplies are common failures..a 300Watt ATX power supply is not very expensive these days so it would be an inexpensive way to see if this is the problem..the brown spot concerns me though..seems maybe you have a filter in the supply that may have leaked electrolyte...if you have another computer with the same type of supply in it..you can try it..as long as the plugs are the same and the wattage is the same or higher

E-Machines... • Answered on Jan 08, 2011

These are fairly cheap units. Just buy a replacement and fit it yourself. The conncetors are made in such a way that you will not make a mistake.

Finding someone to fit it for you will cost you twice the amount of the Power Supply.



E-Machines... • Answered on Jan 06, 2011

Had the same problem myself a few weeks ago.

1) Check the cpu and heatsink are clear of dust and rubbish. If CPU's overheat, the PC can also shut down.

2) If so, then yes it could well be your PSU. Give it a good blow through/clean.
If that doesn't work then it needs to be tested, you can get small testers or go to a repair shop and ask them to test it. But make sure the test is run for about 30 minutes. I had mine tested, paid money, test came out good, but it wasn't run for long enough. Tested again it failed after 15 mins.

3) If you want to avoid that route first, take out the psu, dismantle it and check the printed circuit board, if you see what looks like a yellow fluid stain under some capacitors, one of them has failed. You need to replace it. But as a replacement CPU shouldn't be too much, I wouldn't go to too much trouble, unless I wanted to have the fun of repairing it.

E-Machines... • Answered on Dec 09, 2010

hi follow the output voltage of this capacitor, 5V, 12V, 3.3V and then its simple to knew the value,

E-Machines... • Answered on Oct 27, 2010

Does the fan on the power supply run? As you say the power on switch lights up and so does the motherboard, means that the power supply is working. Monitor gets power from the socket on the power supply. Try plugging it in the wall socket. Try to unplug the main power cord from power supply to the motherboard. The one that has a broad plug at the motherboard end. Replug it and they power on the PC.

E-Machines... • Answered on Sep 11, 2010

It's not your power supply. It's your graphics card that's the problem.

E-Machines... • Answered on Aug 12, 2010

Actually no, the power does continually comes in but, when stopped, the PS is in a state that could be assimilated to stand-by - only a small side circuit is continually operational.

E-Machines... • Answered on Jun 23, 2010

No it is not neccassary to use a E-machine power supply if your previous one has become faulty. You can use any one as long as it has the required power rating.

E-Machines... • Answered on Jun 16, 2010

ok first you disconnect the power supply from motherboard then measure the output voltage if it is ok then there is two wires green and black at o/p of power supply short green and black and see fan is rotating or not if rotating then power supply is ok if not then open the power supply check ac voltage in the pcb if present then check dc voltage after bridge rectifier and ckeck part by part

E-Machines... • Answered on Jun 02, 2010

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