XPS 420 will not turn on

Mystic  Sage,

The diagnostic lights on the XPS 420 are located on the top left front of the cabinet as shown in the front view shown here: 

The diagnostic light codes are described here:   

The power indicator light is the light in the front power button.  The amber or yellow LED on the motherboard turns green when the motherboard is working properly.  If you unplug the power cord and hold down the front power button for 15-20 seconds the motherboard LED should go out.  If it stays amber when the unit is plugged in and the power button is pressed, then you may have a motherboard problem.

Unplug all devices except the keyboard, monitor and mouse.  Unplug the power cord.  Press the power button for 15-20 seconds.  Reconnect the power cord.  Press the power button and watch the diagnostic lights and power button light.  What happens?

Tony

Thanks for responding I did what you said when I connect the power cord no indicator lights turn and and the motherboard LED stays the amber color and when I remove the power cord for a split second something happens and the amber light fades.  In the end it's still not working and from what your saying I might have a motherboard problem rather than a power supply problem or maybe both?

MysticSage,

It surely sounds like a motherboard problem.  If electrolytic capacitors on the motherboard appear swelled on top, you can pretty much figure the motherboard is toast.   However, occasionally a system will go bonkers due to a power line glitch, electromagnetic pulse, or something similar.  Some things you can try are as follows:

Note: Disconnect power.  Press power button to clear "flea" power. 

Remove CMOS battery for a few minutes and then reinstall it.

Remove and reseat memory chips.

Remove all I/O cards such as dial-up modem, network card, and video card.

Disconnect all drive cables from the motherboard.

Clear CMOS.  See the Service Manual referenced in my earlier post on the diagnostic lights.  Note:  Memory chips must be installed when clearing CMOS.

Disconnect all power supply connectors to motherboard and drives.

Let us know what you find.

Tony

Thanks tgsmith,

ugh...it seems it's a never ending problem so I've replaced the CMOS battery and reconnected the power cord and now a blinking yellow light appears on the power button but the amber LED on motherboard is still on then I hit the little switch on the back by the power connector then all of a sudden it turned on.....except its not functioning regularly like normal.  I look at the indicator lights and its showing 1-3 and from the list it means another failure and I'm totally stumped also the LED on motherboard is still on amber color. oh and the screen is showing this .3-B16903-103 RV610 GDDR2_16x16 64bi not sure if it means anything >_>

@MysticSage​ have u solved it? Happend me the same for almost a year ago exactly the same as u, i upgraded my pc with some rams, new gpu and ssd and i try to fix it the powerbutton shows no light but the motherboard shows yellow as it was b4

@tgsmith​ a question i have the same problem as this guy if i change the capacitor will the motherboard work again? If thats the problem ofcourse i havebt checked up the psu yet... 

When troubleshooting a Dell XPS 420 that won't turn on, it's important to go through a series of steps to pinpoint the issue. Here are some steps you can follow:

1. Check the Power Supply and Outlet:

   • Ensure that the power cord is securely connected to both the computer's power supply and a working electrical outlet.
   • Try a different power outlet to rule out issues with the outlet itself.
   • If you have a known working power cord, consider trying it to eliminate the possibility of a faulty cord.

2. Inspect the Power Button and Indicator Light:

   • The "power indicator light" mentioned in Dell's response typically refers to the LED on the computer's power button. It should be solid green when the computer is powered on.
   • If the power button LED is not lit, even when you press it, it could indicate a power supply or motherboard issue.

3. Check Diagnostic LEDs:

   • The diagnostic LEDs mentioned are typically located on the back of the computer near the I/O ports. They are small LEDs labeled 1, 2, 3, and 4. These LEDs can provide information about the computer's status during startup.
   • If none of these LEDs are lit, it suggests that the computer is not receiving power. In this case, it could be a power supply issue.

4. Inspect Inside the Computer:

   • Open the computer case and visually inspect the interior. Check for loose cables, particularly the power connectors from the power supply to the motherboard.
   • Ensure that RAM modules, graphics card (if present), and other components are securely seated in their respective slots.

5. Try a Minimal Boot:

   • Disconnect all peripherals (keyboard, mouse, monitors, USB devices) from the computer.
   • If you have multiple RAM modules, try booting with just one module in the primary RAM slot. If it doesn't work, try the other module.
   • Attempt to power on the computer with only the essential components connected (motherboard, CPU, RAM, power supply). This can help identify if there's a hardware component causing the issue.

6. Listen for Beep Codes (If Available):

   • Some Dell computers may produce beep codes that indicate hardware problems. Listen for any beep sequences when attempting to power on the computer.

7. Inspect the Power Supply Unit (PSU):

   • If none of the above steps resolve the issue, it's possible that the power supply unit has failed. Dell XPS 420 systems are known to have power supply problems over time.
   • Consider testing the PSU or replacing it with a compatible unit. Dell's support or a professional technician can help with this.

8. Consult Dell Support:

   • If you're unable to identify the problem and resolve it on your own, it may be time to contact Dell's customer support for further assistance or consider professional repair services.

Remember to take appropriate safety precautions when working with the inside of your computer, especially when dealing with electrical components. If your XPS 420 is still under warranty, Dell's support should be able to assist you further.

@Gatto Sama​ thank u

@Gatto Sama​ hello i watched only over my capacitors they are fine so what would u say is the problem? im guessing now its 100%  the PSU

I just want to tell u that i fixed mine with same problem the problem was psu (dc) and the psu is repaired now

@Gatto Sama​ hello i just want to tell u my psu was the problem and its fixed now (the dc was the problem)