Slow to start up power supply

E

Electron Mick

New Member
Hi This is my first post as a new member.
I have a DELL Dimension 4600 computer which is now 4 years old. Recently the power supply started to take some time to respond to the mains power being switched on at the wall before the computer front panel momentarily lights up and then goes out. Only after this will the computer start up in the normal way when I press the button on the front panel. First noted with a delay of 5secs it now takes around 30 seconds before I get a response with the PS relay kicking in. If anyone is familiar with this fault and can give me some guidance on repair or has a circuit I would be most grateful.

Electron Mick
 
Could be the PSU...but..remember that the Power supply is "controlled" by the motherboard. Depending on how comfy you are with messing whats "in" the case you can isolate the Power Supply and determine that it either responds on demand or takes more time than it should to come up.

Keep the Computer plugged in but shut off at the rocker switch on the back of the Power Supply. (This helps with removing static electricity...we dont want ESD to kill your Mobo )

Put on your Static wrist strap and clamp on to the computer chassis

First thing you want to do is disconnect the main 20+4 power supply connector into the mother board...and then the smaller P4 connector

You can either use a PSU Checker to plug into the 20+4 connector or just simply short the green and black wires.

Turn the Power Supply Supply switch to the on position. If the Power Supply is healthy, the checker will indicate it...but at the very least you should see and hear the fans spin up immediately.

Isolating the problem component should help point you in the right direction.
 
I have now confirmed the problem lies in the power supply. I guess in the start up circuitry of the SMPS. No output voltages are present to spin up the fans or provide power to the mother board to take control when the button on the front of the computer is pressed until after about 30 seconds from the time power is switched on. Apart from this initial delay the PSU appears to function quite normally.
 
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