No video signal to the Monitor?

[SuRGV]

I hope you guys can help me fix this problem.
I left my computer on last night and when I woke up in the morning, the monitor was black ( I've NEVER set to turn off monitor or harddisks or go to standby if idle for a certain time) but the computer seemed still working as all the fans were still blowing (all case fans, PS fans and CPU fan). Since then, my computer has not been able to boot with video signals. I've tried many things but to no avail. Here are what I've done but none made anything difference:

- Turned off the computer by pressing and holding the Power Switch button (the Reset button now no longer works). Checked all the cables. Turned it on but same thing. NO
- Tried different working monitor. NO
- Tried different working Videocard (ATI Radeon 8500). NO
- Disconnected 2 HDDs on RAID. NO
- Removed Mainboard battery and reset mainboard BIOS using the onboard jumper. NO
- Tried another mainboard battery from the second working computer. NO

I have no clue where the problem lies. As I am writing this post, the computer has been turned on for several hours (of course no video signals) but all components are cool as if never been turned on. All fans are still working. No sound from the HDDs. There is power to all the lights.

Can someone think of something that I can try? Thanks a lot in advance.

BTW, nothing overclocked.

[Wombat]

You might have just lost the MB. Generally, if the CPU were bad, the CPU fan spins up for a second and stops.
And you're not getting any beeps.

It could be the PSU (warm exhuast there?), but I'm leaning towards bad MB.

[SuRGV]

Thanks Wombat for quick response.

There are no beeps at all, only the sound of fans spining up as I turn on the computer.

The exhaust from the PSU is a bit cooler than normal, i guess, since the interior my the case is cooler now with components seem idle.

No !!! the MB death shouldn't be true.

[SpiralDragon]

ay... defently seems like a case of a dead MB..... try removing all your PCI cards and anything else conected to the pc except for the bare minimums... boot drive ..kbd..mous.. and monitor.... if the computer still dosent even beep on boot up well then it should be the MB..... this has hapened to me once not to long ago.. turned out to be a bad NIC card doing something to the bus... the card went out and the PC booted fine

[SuRGV]

SpiralDragon,

I just tried to remove as many things as I can (all CD drives, all PCI cards, printer) but same thing

oh no...Its warranty just ended less than 2 months ago !

[rylan]

If you have a voltmeter check the levels on the power supplies. I'd also make sure something isn't shorting the motherboard to ground. Unscrew the motherboard from the chassis and try it then.
Unfortunately if you don't get the beeps without any cards installed its most likely the motherboard, although I've seen a bad cpu do that also, or if the heatsink shifted and is putting too much pressure on part of the cpu core.

[SuRGV]

Rylan,
I tried another good PSU (Enermax 350W) but it's still the same.
I will try to unscrew the MB as you suggested to see if it will help.

BTW, if the MB is dead (which is very likely), getting another MB means reinstalling the Windows. Do you think I will have problem accessing my encrypted folders on the RAID-1 disks ?

[SuRGV]

was trying to unscrew the MB and discovered that one of the capacitors was burned making a large dark circle on the otherside of the MB!

alright new MB is on its way here. Now nothing to loose with this MB. assuming I will get a right capacitor and with my little soldering skill, do you guys think replacing the capacitor would resurrect this board ?

[Wombat]

Maybe. Your dark circle description sounds like serious damage though.

[Greebe]

quite possibly, but you should change all of them (they are a set so to speak)

Here are two links to those who can either repair or supply you the correct replacement parts.

http://www.motherboardrepair.com/index.php?sec=services

http://www.badcaps.net/kits/

[VJ]

I once had a similar issue... Turns out the resetbutton was pressed permanently (the plastic case button was positioned normally, but the actual button behind the front panel made contact).

As a result, I had no video and no power on the PCI bus.
(took me a while to figure it out; I noticed the leds on my NIC and SCSI card didn't light up)

edit:

Originally posted by SuRGV
was trying to unscrew the MB and discovered that one of the capacitors was burned making a large dark circle on the otherside of the MB!

Whoops... (I should really learn to read the entire thread before I reply)
Best of luck with the repair/new mainboard.

Jörg

[rylan]

Oof, depends on how deep the burn on the board is. Unfortunately when a cap fries like that it can take out another component with it, or one of the regulatory on the board died and cooked the cap.

[SuRGV]

I have a friend whose job is buying electronic components and assemblying them. He said the burned thing is a Filter, not Capacitor (sorry for my near-zero electronics knowledge ) and he will try to replace it if he can find the component.

The darkened area on the otherside of the MB looks scary but it does not seem to damage much (hopefully ). It only looks like the Filter was too hot and got burned, a bit melted. Hopefully the friend will be able to fix it.

[rylan]

Oh burned inductor filter would definately cause something to stop working then, since it acts as a fuse with too much current. Only question is what frequency characteristics it had.

[Kurt]

Originally posted by SuRGV
Rylan,
I tried another good PSU (Enermax 350W) but it's still the same.
I will try to unscrew the MB as you suggested to see if it will help.

BTW, if the MB is dead (which is very likely), getting another MB means reinstalling the Windows. Do you think I will have problem accessing my encrypted folders on the RAID-1 disks ?

You won't necessarily need to reinstall windows. just get a mainboard with the same chipset and make sure the BIOS has the same ACPI settings as the old one (if you remember them).