Computer turns on but no video output

[teknikz]

A couple of days ago my pc froze on me and I had to hold the power switch for it to turn off (no reset button). Computer turned on and worked fine for a bit that night I shut downed properly. I woke up this morning to see that when I hit the power switch on my computer, it turns on beeps once, lights on cd drives flash but no video output. I POST tested and worked but cant seem to figure out the problem. Any help would be nice :)

[Whyzman]

Welcome tohttp://www.pcguide.com/ubb/pcgubb.gif Forums!

Do you have a floppy drive on this machine?

[teknikz]

Yes, I do have a floppy.

[Whyzman]

Two tests I would run:

Memtest86

The Harddrive diagnostics

Both of these are self-booting and will check things out besides loading without Windows...

[teknikz]

Thanks for the reply but, how would I run those tests if I can't see the output on my monitor.


P.S I'm using a perfectly fine PC to use these boards FYI

[Whyzman]

Sorry, I misunderstood. I thought you were able to make it through POST?

If no video...is it onboard or a card?

If a card, I would reseat a few times and retry.

[teknikz]

I tried reseating but still no dice. I've noticed none of the front lights on the computer are on and the monitor stays on standby with the orange light on.

[Paul Komski]

It sounds very likely that you need to replace your PSU.

[teknikz]

I'm pretty sure the PSU is fine because the fans are still spinning.

[Paul Komski]

Just because one part of the DC output is fine doesnt meant that all of it is. I noted particularly that: I've noticed none of the front lights on the computer are on

[teknikz]

Hrm. I`ll try to find a working PSU around somewhere. I don't have the money atm to get a new one =[. I hope this works.

[Sylvander]

"it turns on beeps once, lights on cd drives flash but no video output"
That suggests:
1. The single short beep means that the POST has successfully completed all tests to that point.
Where does your beep normally occur?
Just before attempting to load [an OS] off a drive?
Or just before displaying an image on screen?

2. "lights on cd drives flash"
That's the POST communicating with the optical drives during POST.
Again suggests POST is proceeding normally.
At which point in time during POST do these blinks take place?
In my Phoenix POST they happen when the POST is detecting the drives connected to the IDE controllers.
After the video card is initialised.
Just before the beep and then the BIOS loads off some drive.

"but no video output"
Quite possible that your video card has been successfully initialised; a signal is being sent out from the card; but it isn't reaching the monitor because THE SIGNAL CABLE HAS BECOME DISCONNECTED FROM THE VIDEO CARD SOCKET.
Anyone can produce this effect merely by unplugging the signal cable [or working it loose]. :)
So during startup, everything proceeds normally, but totally unseen.
Usually the monitor complains that it is seeing no input signal.
Yours has gone into standby [orange LED] because of no input signal.

[Paul Komski]

If the front panel lights are not coming on then either the leds have become detached from the mobo headers or the mobo is not getting power or there is primary failure of the mobo itself. The opticals and the PSU fans would be powered by different wires/PSU output and could thus be still receiving power.

[Fruss Tray Ted]

How odd and confusing without trial and error replacing parts or test equipment.

The 12 volt leg seems fine, the fans work. The 5 volt line also due to the optical drives also working. And POST seems to be successful which points to the 3.3 volt leg as sufficient.

I suppose a barebones boot with attempt to get into setup may be feasible for an attempt to rule out HDD or optical failures, even any extra pci cards not necessary which may be disallowing a full boot.

Also, some already asked if this is onboard video or a separate video card. Please post your computer specs (this should be a ROC around here..).

[teknikz]

The card is a separate card. Can't really tell you the specs because my friends uncle gave me the computer after he upgraded.

PS Thanks for all the advice. I'll try the barebones tests.