• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1326
  • Last Modified:

Dell XPS 400, mb light on green, but not power

Hello,

I have a Dell XPS 400, the green light comes on on the motherboard, but when I press the power button, nothing at all happens, I've tried it w/ another power supply w/ no results.

Any suggestions?

Thanks
0
PavPPZ1
Asked:
PavPPZ1
  • 21
  • 10
  • 8
  • +2
1 Solution
 
Peter HartCommented:
disconnect all extras and just leaft the screen attached and switch on. then if nothing
then disconnect and remove the RAM and try again - it should beep twice.
if nothing then its either the mobo or the CPU or both.
check the capacitors on the mobo and see if they are bulging (they should be flat topped)
if bulging - dead mobo
0
 
alecg13Commented:
There might be a problem with the motherboard. Have you check (if you know how) all the connections on the motherboard on the inside of the computer to see if there are any motherboard connections unpluged. You might also want to try holding down the power button when you try to turn on your computer. Otherwise, you might want to consider contacting Dell and see if they can repair it.

Hope this helps!
0
 
PavPPZ1Author Commented:
The capacitors look okay from what I can tell, but I tried what you said, and it still won't turn on, its as if the power button doesn't work at all or something.
0
Protect Your Employees from Wi-Fi Threats

As Wi-Fi growth and popularity continues to climb, not everyone understands the risks that come with connecting to public Wi-Fi or even offering Wi-Fi to employees, visitors and guests. Download the resource kit to make sure your safe wherever business takes you!

 
Peter HartCommented:
sorry must ask - you have connected 2 power leads to the mobo and the switch leads to the mobo?
if so...
sounds like a dead mobo.
0
 
PavPPZ1Author Commented:
yeah they're on, and the green light is lit
0
 
jamietonerCommented:
Could be a bad control panel or control panel cable. This is a PITA but try and trace the power button wires on the ribbon to where it plugs into the motherboard and short the 2 pins with a screwdriver and see if it will power on.
0
 
Peter HartCommented:
could be static - sometimes I've found with dell, - power supplies not working and then after they have been earthed and discharged they work again.
do you have a power supply tester ?(about £10 in the uk)
0
 
nobusCommented:
that's when they go into protection (of ten caused by an overload) some get out quick, or automatic, some have to bleed.
if you want to short the power pins, check if this helps  :
Dell-Power-on.doc
0
 
PavPPZ1Author Commented:
I've tried a different power supply, it does the same thing
0
 
Peter HartCommented:
sounds like the mobo is brown bread (dead)
0
 
PavPPZ1Author Commented:
alright, i'm going to order a replacement motherboard, i'll let you know how it works out
0
 
jamietonerCommented:
Did you try the control panel trick? A control panel is alot cheaper than a motherboard.
0
 
PavPPZ1Author Commented:
What is that?
0
 
jamietonerCommented:
On most dell systems the power button connects to it. Try tracing the power button wires to where it plugs into the motherboard(usually a ribbon cable) and short the 2 pins quickly, if the system turns on the powert button and/or control panel is bad, if it still doesn't turn on then it's the motherboard.
0
 
PavPPZ1Author Commented:
There is one ribbon cable leading to the motherboard, the motherboard connector it goes to has 39 pins, I tried shorting all of them and nothing happened, am I trying it on the right thing do you think?
0
 
PavPPZ1Author Commented:
I ask that because nobus's document shows only 10 pins on receiving end up the motherboard.
0
 
nobusCommented:
you must remove the 20-pin connector, and short those pins on the mobo (the wires can be broken)
0
 
PavPPZ1Author Commented:
I did remove the connector, but on the document you sent, it shows 10 pins on the motheboard end, on the motherboard there are 39
0
 
nobusCommented:
i only drawed 10, but there are 39, as you can see on the picture next to it.
it is ONLY for showing the location!
0
 
PavPPZ1Author Commented:
Ohhh, gotcha, so if I short the two right most pins it should turn on if the motherboard is okay?
0
 
nobusCommented:
i don't thinkk so.
you have the small PCB with small cable (2 right pins there)
connects to      BIG PCB with large cable and this connects straight to the mobo
on the BIG PCB, i pointed out the switch pins are the one under and left of the missing pin; and the 3rd one.
is that more clear ?
0
 
nobusCommented:
...to show which pins on the MOBO you can short
0
 
PavPPZ1Author Commented:
Okay, I ordered the new motherboard, I'll let you know how it works out, thanks for all the suggestions so far!
0
 
Peter HartCommented:
hopefully its not the CPU ? ;-o
0
 
PavPPZ1Author Commented:
If it was just the CPU wouldn't it at least power up, fans come on or anything?
0
 
Peter HartCommented:
as far as I know the CPU tells the motherbnoard what to do. without the CPU the motherboard is like a body wityhout a brain.....
having said that - it could  be the motherboard is dead and not the CPU. or it could be both or it could be the CPu. sorry.
0
 
nobusCommented:
odds are 95% mobo, 5% cpu failure
so normally, it is the mobo
0
 
PavPPZ1Author Commented:
So I replaced the MB and the same exact thing happens.
0
 
Peter HartCommented:
what motherboard did you get? a dell replacement ?
I assume its got the same pin outs for the switch, power....capatible CPU....
0
 
PavPPZ1Author Commented:
same exact motherboard that was in it
0
 
nobusCommented:
then it looks like you hit the 5% ..
0
 
PavPPZ1Author Commented:
shouldn't it at least power up even w/ a bad cpu though? generally the fans etc will at least come on, i'll try another one though
0
 
PavPPZ1Author Commented:
It does the same thing w/ another processor as well.
0
 
nobusCommented:
that would depend on the actual fault
an example : if you keep the reset button closed,  try booring, and see what happens...
0
 
PavPPZ1Author Commented:
There is no reset button, and I don't know what you mean by "booring"
0
 
nobusCommented:
booting
0
 
PavPPZ1Author Commented:
oh, when you press the power button absolutely nothing at all happens, so i can't try booting
0
 
jamietonerCommented:
I would replace the control panel(also called i/o panel), the i/o panel cable and the power button. I'd get the cable first(part# Y8227) as I've seen these get pinched and cause issues similar to yours, then the power button(part# J8995), then the i/o panel(part# f8912). These I think are much more likely to cause this issue than a bad cpu. These parts can be found on ebay(cheapest place), from impact computers(www.impactcomputers.com) and from Dell(usually expensive).
0
 
PavPPZ1Author Commented:
So the motherboard was probably fine, its just these parts?
0
 
jamietonerCommented:
Probably.
0
 
PavPPZ1Author Commented:
Why would the audio/usb board need to be replaced?
0
 
jamietonerCommented:
The power button connects to it, a short in it would cause the power button to not function.
0
 
PavPPZ1Author Commented:
Any suggestions on which one I should start w/ to replace instead of having to buy them all?
0
 
Peter HartCommented:
is the motherboard (both versions) seated correctly on the chassis ? have you tried a new power supply on the new motherboard - maybe the old motherboard shorted out any power supply and so when you changed the mobo  - no work  - as the power supply was stuffed by the last mobo.
just a thought. double check the earth and the power supply.
0
 
nobusCommented:
i was answering to your question "shouldn't it at least power up even w/ a bad cpu though? generally the fans etc will at least come on"
and i said  (on a normal working pc) to hold the reset button , and try booting
then NOTHING happens, since the cpu is kept in a reset condition
and yes, i KNOW you can't boot
0
 
PavPPZ1Author Commented:
Thanks so much 100% right, I had tried another PSU before replacing the motherboard, not not after, tried another one after putting in the new MB and it came right on, thanks again!
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

  • 21
  • 10
  • 8
  • +2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now