Deminsion 8400 power problems

Never have any diag lights come on.

No beeps... NO display

Checked Mother Board... see No charring and I see NO bulged capacitors

Tried new power supply got same problem. Power supply FAN will NOT come on either, but if I unplug the 4 pin 12 volt connector, fan will come on and power light stays amber.

awjacobs

Check the sequence of the diagnostic lights on the back panel of the case  HERE.

Are there any 'Beeps', or error messages?

Also, check the motherboard for any capacitors with bulging tops or are leaking, the tops should be perfectly flat.c

Check the motherboard's 4-pin and 24-pin power connectors, to see if they are charred or burnt.

Bev.

Tried what you said with the power supply... Power Supply Fan Works.

I plugged the 24 pin back in to the MB and removed ALL cables to all HDs and DVDs. Removed Video card and ALL externals.

NOTHING, just the blinking Amber light. :)

Like I said, if I power it off, remove the 4 pin 12 volt connector and power back on. The fan works and the Amber light is solid.

NO, Beeps, no Diag lights nothing.

As much as I DID NOT WANT TO HEAR IT, I think you are correct... Mother Board. ARGGGG

What to do from here? Is it worth buying a New/Refurbed Motherboard?

awjacobs

Solid Amber, or Blinking Amber?

As there are no 'Beeps', or Diagnostic Lights, it could be a bad motherboard.

If you are comfortable working around computers, you could try the following:

Unplug the cord from the power supply, hold the power button in for about 15/20 seconds, open the case, unplug the 24-pin power connector from the motherboard and jump the Green wire to one of the Black wires, reconnect the power cord and power the system, if power supply's fan and the hard drive runs, then the PSU should be good.

Note: Do not remove any wires from the plug, use a small piece of wire or a paper clip as a jumper.

Power supply checks out and the system still does not work, again remove the power cord, hold the power button in for several seconds to discharge the residue power, reconnect the 24-pin connector to the motherboard.

Remove all the PCI cards, the video card [if applicable], memory, all peripherals, disconnect the data and power cables to all the drives, check that the front panel cable is connected to motherboard, with nothing else connected to the system, reconnect the power cable and power the system on.

If you do not get any beep codes and/or there is no change in the diagnostic lights, then it would appear that the motherboard has died.

Bev.

awjacobs

That's a bummer.   :emotion-6:

A refurbished Dell OEM, 8400 motherboard can be purchased from HERE for $119.99.

But, if you check eBay, you will find working Dimension 8400 are being sold for around $200+-, as the replacement cost more than 50% of the system value, it maybe more advisable, to put the $120 towards buying a new Quad Core, Windows 7 system, plus an obsolete system like the 8400 can become a money pit.

Bev.

I have a Dell Vostro 1720, and would prefer getting away from the Big Clunker anyway (although, I loved that machine). BUT, I have 2 Hard Drives, DVD WRITER memory.. that I have to do something with. :(  I will think on it.

Thank you very much!

You have been a big help!

tony

Tony.

Happy to have helped.

I know how you feel about the 8400, I had two of them and sold the last one, on eBay two/three months ago.    :emotion-9:

Bev.