|I took a look on the web.|
There are used PSs for this model (XPS 400, 410, 420) on the web. I don't recommend you buy any used power supply.
- many have wires coming out of the bottom of them rather than the back, or from both the bottom and the back, of the PS (???)
- I see no test button on the back of any of them
If you have no test button........
Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this:
New replacement PSs listed on the web for this model are a standard size and have all the wires coming out of the back of the PS, the standard way.
I looked at the Dell Owners manual for XPS 420
- It appears there's no reason you couldn't use a power supply with the wires coming out of the back of the PS the standard way - there's enough room inside thecase.
"Removing the Computer Cover
"Lay your computer on its side with the computer cover facing up."
(The left side as seen when you face the front of the computer faces upwards)
"Pull back the cover release latch on the top panel."
Remove, replace the power supply; required connectors
According to info here:
XPS 420 FAQ
this model came with either a 375 or 425 watt power supply.
The mboard has a PCI-E X16 slot for a video card.
If you need to replace the power supply,
- one that has the same wattage capacity, or more, is fine, unless the PCI-E X16 video card has been replaced with one that requires a greater power supply capacity, or you think you might require one with more capacity for a better video card in the future. One that has a 600 watt capacity or greater will handle any current PCI-E X16 card.
- get a decent power supply, not the cheapest one you can find.
See response 3 in this: