Member Avatar for dj admz

Hi there guys!

Got problem on the unit itself.. The motherboard of the unit has power but won't turn on.. I'd tried to replace the power supply unit but the same problem persist... I have two units of these and both have same problem.. I've already tested the power supplies and they are all good.. I had changed the CMOS battery.. still same result...

Please give me any idea on how to fix this problem without changing the motherboard.. (if there is any)

Thanks

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  • Latest Post Latest Post by System Jay

Dani AI

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Quick, practical bench checklist and diagnostic tips for the Dimension 4400 situation described by — both boxes show the standby LED but neither responds. Several members have suggested the usual swaps; below are focused, testable steps and checks that go beyond simply changing PSU/RAM and help pinpoint whether the board, front-panel wiring, BIOS, or a short is to blame.

  • Verify the front-panel power switch and header: unplug the case connector and momentarily short the two power pins on the motherboard (with the PSU connected to mains) to emulate the button. If that starts the system the front switch/header/cable is the culprit. If you don’t hear POST beeps, attach a known-good PC speaker to the board’s speaker pins — many systems ship without a speaker so beep codes may be missed.
  • Measure standby and start signals: with a multimeter confirm ~5V on the standby rail (5VSB). Then watch the PSU’s “PS_ON” signal while pressing the power button; the board must pull that lead low to start the PSU. If 5VSB is present but PS_ON is never asserted, the motherboard isn’t issuing the start command.
  • Rule out chassis short and bad caps: bench the board on a non-conductive surface (remove from the case) and try the above again. Inspect closely for bulging/leaking electrolytic capacitors, burned components, or swollen voltage-regulator parts near the CPU power area — these fail on older Dells and can produce a totally silent board.
  • BIOS/firmware and repair options: a dead or corrupted BIOS/EC chip can prevent any power-up; if the BIOS chip is socketed a swap or reflash (with proper equipment) can revive the board. If advanced checks show 5VSB present but no start and no obvious shorts, the next sensible step is either a board-level repair (capacitor replacement, MOSFET check) or sourcing a donor board that lets you salvage CPU/RAM.

If you’re not comfortable with mains wiring or PCB-level testing, stop and seek a technician. These steps show whether the board is merely silent or truly irrecoverable, and will make any repair shop work cheaper and faster.

Recommended Answers

All 9 Replies

Member Avatar for ramjo

Do you hear any POST (Power On Self Test) when you boot up the machine? If not it means your motherboard or a hardware within it has a problem

Member Avatar for khakilang

If you heard several beep sound than it maybe be the graphic card or RAM than is having the problem. If not than it could be your motherboard.

Member Avatar for dj admz

Do you hear any POST (Power On Self Test) when you boot up the machine? If not it means your motherboard or a hardware within it has a problem

I don't hear any beep sounds (which is weird). The motherboard won't react to any thing.

Member Avatar for dj admz

If you heard several beep sound than it maybe be the graphic card or RAM than is having the problem. If not than it could be your motherboard.

No beep sounds sir. I've tried to change the memory cards and the graphic card, as I did changing the power supply and HDD's. Still nothing, but the flea power light of the motherboard is on.

Member Avatar for airbourne

No beep sounds, no fans, nothing means: motherboard is bad. Sometimes a bad motherboard can affect the CPU, sometimes it doesn't. To fix the problem your only option is to at least replace the motherboard. :(

Member Avatar for dj admz

No beep sounds, no fans, nothing means: motherboard is bad. Sometimes a bad motherboard can affect the CPU, sometimes it doesn't. To fix the problem your only option is to at least replace the motherboard. :(

Yes sir I'm thinking of it too. I might have a dead motherboard. but I'm still looking for any solution to the problem. Thank you

Member Avatar for benmar

no beep, no sound anything, no bios. means motherboard is 95% dead...

Member Avatar for crunchie

What about the other 5%? Is that still good?

Member Avatar for System Jay

Remove all components and start the machine. if you get a post boot. start adding components 1 by 1.

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