Member Avatar for akirson

This is a Dell Dimension 4500 that was working fine, and then was switched off for a few months. Now, when plugged in, the green LED on the mobo lights up, and there is faint green glow behind the power switch, but pressing the power switch does absolutely nothing. The disks don't spin up, no beeps, nothing. Also, the LEDs next to the Ethernet port don't light up at all. Usually they light up even when the computer is powered down.

I tested the PS - works fine
CMOS battery - AOK
Switch on the front panel - OK
No visible signs of blown caps, swollen caps, no evidence of anything burnt.

I tried resetting the CMOS by removing the battery for a minute or two - no go.

What is the absolute minimum config to see if it will turn on? There is no built-in display adapter on the mobo - separate card. It should show signs of life even without hard drives, right? What about RAM?

Any help will be appreciated.

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  • Latest Post Latest Post by coolraj003

Dani AI

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Building on advice from and the PSU question from , here is a compact, actionable bench checklist and what each result usually points to. The aim is to isolate PSU, front-panel/power logic, and the motherboard power circuitry without repeating tests already mentioned in the thread.

Recommended bench checklist:

  • Remove all drives and expansion cards; leave only the PSU, motherboard, CPU with cooler, and one known-good DIMM (use the first DIMM slot on the board). Attach a system speaker if available.
  • Ensure both the main ATX cable and the 4-pin/8-pin CPU power connector are seated. Some failures are simply the CPU power lead not plugged in.
  • Try shorting the two power-switch pins on the front-panel header briefly to rule out a bad case switch or harness.
  • If a PSU bench-start is needed, short the PS_ON (green) to a ground (black) to spin the supply and then measure rails with a multimeter rather than relying solely on LED testers.

What to measure and how to read it:

  • Check +5VSB (purple wire on the ATX connector) — its presence means the board can accept a power-on request. If +5VSB exists but PS_ON (green) is never pulled low by the board, the motherboard’s power-control logic may be dead.
  • Measure the main rails (+3.3V, +5V, +12V) under load or swap in a known-good PSU. Simple LED testers can miss faults that appear under CPU load.
  • If no POST/beeps occur, confirm the small speaker is connected; many boards will give no video but will give beep codes.

Dell notes and final pointers:

  • Dell front-panel or I/O daughter boards and proprietary connectors can fail; verify cables and the little front board behind the bezel.
  • Electrolytic caps can fail without obvious bulging; also check for mis-seated standoffs or motherboard shorts.
  • If bench isolation points to the motherboard, replacement (used OEM boards) or component-level repair is often the pragmatic route. Use insulated tools and basic ESD/mains safety while testing.

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Member Avatar for coolraj003

Try starting it with just the mobo, psu and cpu with heatsink/fan. See if it gets you some display. As you say the psu is ok, it should power up. No memory means it wont go far but definitely take you to the BIOS. Have a check. Is it fails then it could most likely be the mobo and thats what i am inclining towards as well.

Raj

Member Avatar for sittas87

Welcome akirson
mind me askin how did you test the PSU? you say theres no power at all?
??

Member Avatar for akirson

I tested the PSU by plugging it into a tester. It beeped and all the voltages are present.

Member Avatar for coolraj003

you can always double check by hooking up with another PSU if yu have access to any and see if it brings any change. But yeah make sure you boot it up with just cpu(with heatsink/cooler) and mobo without any ram installed and see what you get. Do let us know and we ll look into it further.

Raj

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