LED on MOBO lights, no power up.

I've got a problem with a Dell Optiples 755.

When I plug it in, the fan doesn't spin as is typical with most dells. (Most Dells fans will spin when you plug power in)

When I push the power button, nothing happens. I have noticed that there is an LED that is lit on the MoBo, so it appears it has power.

Any suggestions?

Is it the PS?
7 answers Last reply
More about mobo lights power
  1. I assume the PC worked fine before now ? If so I would say the PSU.
  2. The LED on the motherboard simply indicates that the PSU is plugged in and the PSU switch is on. The LED is powered by the standby power supply, a small 5 volt power supply separate from the main section that provides power to the whole computer.

    I'd look at the PSU first also.
  3. Probably the psu, but one other small possibility may be worth mentioning.

    If the cpu fan does not come on, the system will not start up. If you can see *any* evidence (other than the LED) that the system is trying to start up, it may be a dead cpu fan.

    Again, its most likely the psu.
  4. If you have a videocard in the system, take it out and use the onboard graphics to see if that makes the problem go away.
  5. I took out the video card, and that did not fix anything, I then hooked up an extra PSU I have that is brand new, that did not fix anything either. So, would it be the CPU fan, memory, or what?

    Note: neither the CPU fan or the Graphics fans are spinning up.
  6. Since you've already tried a different PSU, I'll presume that the second PSU worked in a different syste, and will rule that out for now.

    Check the obvious first such as the front panel headers. Is the 2-pin power on connector plugged in?

    Is your motherboard the type with two separate connectors for power, a 4 pin and a 20 pin that are in separate locations on the motherboard?
  7. Just FYI
    I had same issue and I replace the PSU. It works for me
Ask a new question

Read More

Power Supplies Power Up Power LED Monitor Components