No video input on monitor, cant see POST, HDD sounds ok keyboard lightcan toggle

[futbolfan]

last night was doing some video editing when bam screen goes black. Rebooted - i can hear the HDD working, but on my monitor it says "No Video Input" - after a while, i hear the windows chime turn on, my keyboard caps lock can be toggled but no display - so i assume it was able to post and load windows but just no display

- rebooting did not work, same as above


i've reseated ram, components, tried video card on another pc - worked - tried monitor with another pc - worked, moved video card to another slot - same problem
disconnected all power except for boot drive, video and normal motherboard connectors

reset cmos, remove battery,

same effect- i know it is booting, ram test with mobo elicits the right number of beeps
scoured the web for answers, it turns out this seems to be a common problem but no common solution -
only thing i haven't tried is replacing ram

so posting it here in case some of ya might have an idea or two to check out

my system core i7-920, 6GB RAM, ATI4850, Win 7 64 home premium, 400w ps

 

[mailpup]

I'd say the power supply may have failed such that it no longer provides enough power to the graphics card even though it can supply some power to other parts of the PC. A 450W or greater PSU is recommended for the Radeon HD 4850.

 

[Archean]

450 Watt or greater power supply with 75 Watt 6-pin PCI Express power connector is recommended for this graphics card; so i guess mailpup's diagnostic seems very plausible to me.

 

[futbolfan]

thanks Archean and mailpup - will try out another power supply
incidentally does this underpowered power supply preclude the pc working previously ? it worked for a good 6-8 months before
but i must admit this past week i started to hear the fan turn up louder (couldn't tell if it was gfx fan or ps fan)

 

[Archean]

Overtime with use the components of the power supply may have been degraded much faster due to heavier load. Anyhow; can you check the graphics card's temperature with ATI's tools installed with the drivers.

 

[futbolfan]

i can try to check it installed in a different pc - can't get past the 'no video input' in the problematic pc

Overtime with use the components of the powerfully may have been degraded much faster due to heavier load. Anyhow; can you check the graphics card's temperature with ATI's tools installed with the drivers.

 

[Archean]

If you can please do so; perhaps both the suspects i.e. PSU & graphics card.

 

[futbolfan]

oh and another thing - in a another forum, it was suggested that the battery (for cmos) might be bad - how likely is this as a possible cause? cheap enough to try it when i get home, but wondering if it's the wrong rabbit hole

 

[Archean]

I am not sure it may be the cause; but there is no harm in changing the cmos battery its dirt cheap anyway when compared to other components.

 

[futbolfan]

thanks archean - will try that as well
question on the graphics temperatur - what should i expect? if it is within tolerance does it rule it out as a culprit?

 

[Archean]

the answer in that case have to be yes.

 

[futbolfan]

no video input no post on boot - SOLVED

unlikely as it may seem teh solution was replacing the CMOS battery - yes a $0.73 cent battery brought a $1000 system down

replaced the battery and everything booted up with display

 

[Archean]

oh well; such is perils of tech but I'm glad rest is just fine, enjoy and peace.