The computer is a Dell Dimension (300?). It uses the standard 24 pin supply. The computer will not power up. With the PSU disconnected or connected to the MB I can read approximately 5V on the Supply voltage pin and +3.85V on the Power On pin which I believe to be correct in the PSU off state. This computer uses a power switch/USB circuit card for power up. I have tested this card in another unit and it functioned normally. I measured +3.84V on input connector and across switch (switch open) as well as 0V (switch closed). The +5V supply was on in both states. In the unit in question the voltage across the power switch (switch open) is low at only +0.75V (even though the PSU input connector still measures 3.84). So I am dropping approximately 3V somewhere on the MB. This is the case whether the CPU is installed or removed. Where should I look for the voltage loss? Is there a component(s) sharing this signal line? Where on the MB does this Power On signal go...CPU...RAM...etc? Any help would be appreciated.
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The Dell Dimension 300 gets the amber blinking light when there is power to the computer (the power supply) but the motherboard isn't getting the correct power. Sometimes it can indicate a motherboard fault or that the power supply is not set to the correct incoming voltage.
Check the back of the computer. If the power supply has a switch for incoming voltage, make sure that it matches your incoming voltage. Next check that the main power cable (20 or 24 pins depending on the computer) is fully seated on the motherboard. (It can only be connected one way and should lock onto the connector on the motherboard.)
Next check that the power supply is providing the correct power. You can simply install another power supply (known to work on another computer). Make sure that the PSU is correctly sized for the computer components. Alternatively use a multimeter or a dedicated power supply tester or put it in a different machine.
If the problem is not cured with a new PSU, the motherboard has a failure. Unfortunately, it's difficult to identify the exact bad component. (If a major component other than the CPU on the motherboard had failed, the diagnostic lights or beep codes could help identify the issue.)
hi!, ok, is there any voltage appear in one of the terminal of psu or power supply is the fan of psu is running,if you suspected your psu is running or not try to unplug and disconnect your psu from the mother board,then bigger socket that contain 24 pin with different color of your psu try to connect the two pin that has a color blue and green by a small wire about 2 inches slotted at both end.then put power if the fan is run its good may be your memory or video card or processor is defected if your psu does not run replace.
This indicates power supply failure. PSU means Power Supply Unit.
Solution? Replace the power supply. MAKE SURE it is a compatible one!
What do I mean by that statement? In some years of Dell manufacturing, Dell made their computers "Proprietary". This means only Dell parts could be used in a Dell computer.
The wires in the 20/24-pin ATX main (Motherboard) power cable, were put in different socket holes, than a standard 20/24-pin main power cable. Yellow is 12 volts. Orange is 3.3 volts. Red is 5 volts. Black wires are Ground wires.
If an aftermarket power supply made by another manufacturer, were to be used in these type of computers, it will burn out the motherboard! Possibly the ram memory and processor also!
If you buy an aftermarket power supply, instead of a Dell unit, make SURE the colors of the wires are in the same place, as they are in the Dell 20/24-pin main power cable connector!
For more info about that last statement, I suggest you check out this page, http://www.playtool.com/pages/psuconnectors/connectors.html
Hi there. Rocket Fish RF-550wps PSU is standard ATX power supply. Dell tend to use their own power supplies which differ slightly from standard power supplies. I suggest you take or send the Rocket Fish RF-550wps PSU back as it won't fit and order one from Dell themselves, at least then you will have a guaranteed fit. Once you have your new power supply from Dell (or a Dell ATX power supply) it should be easy to fit in. Post back if you need any more help.
Be sure that the ATX or BTX power cable (the rectangular cable with 20 or 24 pins) is securely fit into the motherboard. Re-seat it if needed. Also, check the +12V 4-pin adapter (if exists) is seated, just like the 20/24 pin is. If that doesn't solve the problem, be sure that the PSU is switched on and is at 120V (USA) before plugging in the power cable. If that doesn't work, contact the computer manufacturer or the PSU manufacturer (depdending on what you purchased.)
there are fuses inside psu`s some are solderd and some pop out it i would suggest that u throw the psu away and buy new chances are that it will only cause continues and may even result in complete mobo failure problems heres a link to a cheap psu http://www.microdirect.co.uk/(3649)400W-P4AMD-quiet-PSU-with-PFC-20-pin-24-pin.aspx or a more upmarket more powerfull http://www.microdirect.co.uk/(11879)ThermalTake-TR2-500W-Black-Silent-ATX-12V.aspx the choice is yours.