Power supply problems?

frogmaster · 10 May 2012

I own a Dell Optiplex 745, minitower, and I do not understand what my problem is. It has a standard, 350 watt power supply with a 24 pin connector and I tried to replace it with a new ATX 750 watt power supply with the same 24 pin connector. I plugged in everything properly (I triple checked) and every time I try to start the computer, the Dell loading screen pops up as usual, but it stops loading and the computer makes a rapid beeping sound and stays like that (with the loading screen frozen and computer beeping) till you turn it off. Is there a way for me to tell if the power supply is bad or if it's not compatible with my computer..?

linnemeyerhere · 10 May 2012

Did you plug in the mobo 4 or 8 pin 12v connector?
http://www.brighthub.com/computing/h...les/26362.aspx

PooMan UK · 10 May 2012

Hiya pal

Continuous long beeps normally means your Graphics card is not inserted properly or you haven't connected the power supply to it (if needed)

Continuous short beeps normally means a power error

Continuous short to medium beeps can represent a memory problem (Try running a single stick in each of the slots and make sure they are seated properly)

Hope this helps a bit

TVeblen · 10 May 2012

Is there a pattern to the beeps?

Here is a list of typical Dell beep codes:
Documentation
Down towards the bottom of the list.

frogmaster · 11 May 2012

The beeps were continuous and short; I am almost completely positive they signified a power error. I plugged in everything that my computer had previously connected, and could find no additional ports to connect on the motherboard or any other internal devices.

linnemeyerhere · 11 May 2012

What is the make and model of this PSU?

frogmaster · 11 May 2012

The new one is a FSP750-80EPN 750 Watt ATX Power Supply. FSP FSP750-80EPN 750 Watt ATX Power Supply

TVeblen · 12 May 2012

That is a very 'inexpensive' power supply. The likelihood that it is defective has risen.

There could also be a short circuit somewhere. You want to visually inspect the board and the connections for any damage/defects.

If you have a multimeter you can test the power supply's connectors for proper voltage, particularly 12v on the yellow lines.

Why did you decide to replace the power supply in the first place? To solve a problem? What was the problem?

FaberTech · 12 May 2012

A long shot, but I have had to reset the cmos before to get a new power supply to work. give it a try.

frogmaster · 12 May 2012

I am going to try what you said, FaberTech, and with any amount of luck it will work. I do own a multimeter and will try to test the thing for short circuits too. A couple weeks back I bought a graphics card that required a greater power supply than I had in my machine, so the best option was to upgrade the supply instead of buying another card. I figured it would be better for the electric bill anyway.