Dell Desktop Inspiron 620 won't switch on

Hi Assasin_creed00,

How comfortable are you with electronics? What I would do is try the paperclip trick to test the power supply.

I'm not sure what could have happened but depending on how the power was disconnected, you could have a bad power button, power supply or motherboard.

Thank you for replying.

I am quite into electronics and I have built PC's from ground up and stuff so I am not that novice with it.

I did try to short pin 16(green) and black and yes power supply does switch on and its fan works so its not a power supply issue. I have removed almost everything form the motherboard i.e. Hard drives and LAN/Wifi cards - I also removed both RAM chips and then installed one RAM module back.

When I plug the cable into the pc - there is light behind the powersupply and the red light on the motherboard is also lit. I suspect it is the power  button in the ATX casing that is causing the problem.

Is there any specification of that button's cable - I can short that power switch cable if i know which cable is of the power switch

Let me know.

Ok here is a quick update. So on some random thread over the internet I read the tip to disconnect the front panel USB panel's cable that is going into Mother board and yes that did the trick.

Removing the Front USB panel's cable from motherboard has got the job done - I am not sure why that is - but I will investigate and post for future reference

Removing the Front USB panel's cable from motherboard has got the job done - I am not sure why that is - but I will investigate and post for future reference

Are there any bent pins in the sockets?

Hello: i am unable to power on my Inspiron 620 and am willing to try to disconnect the "USB panel's cable" from the motherboard but am uncertain which cable to remove. On the front panel is a "block" about 4" wide and 1" high housing two USB ports with 3 black cables (each about 1/4" diameter) going to the motherboard. Is one (or more) of these the "USB panel's cable" that shd be disconnected from motherboard ?

Bewildered

There appear to be FIVE ports on "front i/o panel" (2 USB; 2 audio; 1 unidentified) but only THREE plugs on motherboard. If the problem persists and if none of the 5 ports is used can the plugs be permanently disconnected from the motherboard ?

UPDATE :  the 3 cables were still connected to motherboard during power on - it failed. When they were unplugged from motherboard power on works as advertised. It's a mystery to me why signal cables should prohibit power on but at least a work-around has been found.

Still Bewildered

Thanks to all who posted this fix. I just had the exact same symptoms from a Dell 620. I couldn't get the computer to not power on. The customer would take it home, plug everything in, get it to turn on once, and then after that it would not come on again. They brought it back to me for repair and I couldn't get it to fail to power on. They took it home and same problem again. After reading this thread the light bulb came on.  I asked my customer if she plugged anything into the front usb ports. She said she had always plugged her keyboard in the front. In all my testing I had always plugged the keyboard into the back usb port.  So I had here move the keyboard to a back usb port. Guess what, it powered on without a problem. She'll let me know if it stops coming on but not having anything plugged into the front usb ports when powering on the 620 seems to be the answer.  Don't know what the fault is in the Dell motherboard for the front usb ports (or the port itself) but maybe there is some kind of a 5Vdc fault or overload condition that the crowbar circuit in the power supply is detecting and prevents it from powering on. 

After purchasing a new Dell power supply and installing, nothing happened.  Read this information and cannot believe that after disconnecting two of the USB cables the computer powered on... so frustrating!  Our 620 Desktop has been so reliable until our last power outage.  Just figured it was time for a new power supply.

Dell needs to find out what is causing this and posting on this site so we can repair them.  I just kept the cables disconnected for now.  Thanks to all those that figured this out or we may have just bought a new computer.

UPDATE - the original bug (failure to power on) returned with a vengeance ! A replacement power button cable assy was purchased long ago and seemed to fix the bug but for some unknown reason recently failed. The original cable assy that came with the machine was re-installed but it too failed. Since there is a spring-loaded button which, when pressed, starts the power on sequence it seemed reasonable that both switches (original and replacement) were defective. The switch was removed from one cable assy and the 2 leads were "shorted" together - power on started but quit after only 1 second ("one small step for man"). However by "un-shorting" the 2 leads and just touching them together briefly the power usually turns on. But on one trial a USB device had to be removed from a REAR port before the machine started. Apparently the tech gremlins have taken control of this from Dell. They used to make sturdy equipment but apparently have decided to focus on profits by using cheap components and refusing to make needed upgrades for their faulty machines.

Bewildered

I bought an Inspiron 620 slim back in September 2011 and has worked great until today. I had the same problem as reported in this forum.

So I just unplugged the front panel USB connector (USBF1), the one that has a green plug on the end of it, and the PC started. I then turned it off, plug the cable back in and it started again. I then tested the front USB ports and memory card reader and everything worked.

I'm hoping this will not happen again, but if it does, I can live without the front USB ports.

Hope this helps.

Thanks to all who posted before regarding this problem.

My 2 cents: Removed front usbf2 from motherboard and restarted computer with no problems. What gives, Dell?