Can't detect input signal on monitor.

[Tisane]

Hello,

So last week I've bought a new graphics-card for my computer, but I can't get it to work. Now first of all, I'm not a computer expert. Anyway, I've bought a AMD Radeon HD 6850 Sapphire 1GB graphics-card. And replaced my old AMD Radeon card for it. Once I started up my computer, I kept getting the message ''No input signal'' and than the monitor would go immediately to sleep again. Today I've been a computer-store with it and they told it must be because I was using a 250W power supply. And for the Radeon HD 6850 a minimum required power supply of 500W is required according to the product information and the computer-store. So we though that must have been the reason why the monitor doesn't load. So I've bought a 500w power supply today. And we placed both the power supply and video card correctly. But AGAIN the monitor says ''no input signal'' and goes to sleep right after again. There is no visible damage to any of the computer parts and everything seems to be working fine by the sounds and view of it, except the monitor not loading. I really got no idea what to do anymore. Does anyone have any advice? I've looked around on the internet all day and I can't find anything helpful. We've checked every component of the computer, changed cables etc, and everything looks just fine. So I hope someone is out there with a golden advice.

Thanks in advance,

Tisane

[Deleted]

It's possible that trying to boot with insufficient (low quality) PSU fried out something. Still, just in case, are the GPU's additional power cables connected?

E: Does the system work with old GPU?

[Butler to Baby Sloths]

Have you tried hooking the monitor up to the motherboard's video output (if it has it)?

[Whidbey]

I'll shoot a wild guess you have a AOC brand monitor, as I had this happen when i bought a Radeon 6570 hd card. For some reason the Radeon hd cards seem to get into this funk where they think they are sending signal fully when they are actually half asleep. Not an issue with a lot of monitors, but the AOC ones won't wake up with that low of a signal.
My remedy is the power down the computer, shut off the rocker switch on the power supply for 5-6 seconds, turn it back on, then power up the system. I forces a hard reset of the vid card and clears any interference with the signal.
If that doesn't help.. I'd try to keep looking for an answer.

One other question though.. did you hook the 12v power line to the front of the vid card?? A lot of cards require 12v off the rail lines plugged into the front. I know my radeon hd does.

[Tisane]

It's possible that trying to boot with insufficient (low quality) PSU fried out something. Still, just in case, are the GPU's additional power cables connected?

E: Does the system work with old GPU?

I don't think the PSU friend out anything, anyway not that I noticed something. The GPU cables are connected. But my PSU has some cables left which I can't plug into anything. And it doesn't look the leftovers have to be plugged into anything as my previous PSU had less cables as the new PSU. So I used all the cables which I used with my old PSU. And for the leftover cables I can't find anything to plug them into.

[Xosimos]

I'm curious if you have an AOC monitor too. I have one and mine wouldn't work with a Universal Monitor Cable. I tried to set up my computer at a friends house one time and it wouldn't work because it didn't like the cable for some reason. It gave me the ''No input signal'' when I tried to load my admin account, but worked fine when I tried it in Safe Mode.

[Tisane]

I'll shoot a wild guess you have a AOC brand monitor, as I had this happen when i bought a Radeon 6570 hd card. For some reason the Radeon hd cards seem to get into this funk where they think they are sending signal fully when they are actually half asleep. Not an issue with a lot of monitors, but the AOC ones won't wake up with that low of a signal.
My remedy is the power down the computer, shut off the rocker switch on the power supply for 5-6 seconds, turn it back on, then power up the system. I forces a hard reset of the vid card and clears any interference with the signal.
If that doesn't help.. I'd try to keep looking for an answer.

One other question though.. did you hook the 12v power line to the front of the vid card?? A lot of cards require 12v off the rail lines plugged into the front. I know my radeon hd does.

I've got a HP monitor, and I've hooked the powerline to the front of my videocard. Tried the rocker switch on my PSU, but didn't help.