I recently did an upgrade of my PC and replaced the CPU and video card; I later replaced the Power Supply and then the motherboard was fried so I had to replace that. I finally got all the components to work and powered it on. I previously had an NVIDIA card (GeForce 9500GT) and the new card is an ATI (Sapphire Radeon HD 7850) so when it powered on I installed the ATI drivers and uninstalled the NVIDIA drivers. This lasted about 30 minutes until suddenly my monitor's screen went black, the power light turned yellow and I got "No Signal".

Now, I cannot get any signal to the monitor with my brand new gfx card. My old card works. Specs are:

CPU: AMD Phenom II X4 965 Black

Motherboard: ASUS M5A97 R2.0

Video Card: Sapphire Radeon HD 7850 (new), NVIDIA GeForce 9500GT (old)

Power Supply: Thermaltake TR2 700W

I just bought the graphics card around a month ago. What strikes me as odd is that it turned on and worked fine for 30 minutes, and then just went, mysteriously after I uninstalled the old NVIDIA graphics card drivers (however reinstalling them didn't fix the problem).

Since it's a bit confusing with the chain of events, here is the timeline:

  1. Buy new CPU and Gfx Card from Newegg

  2. Try to install gfx card and CPU; get "No Signal". Discover that I need more than a 300W power supply. Order a 600W power supply.

  3. Try (and fail) to connect power supply. Bring PC to a local repair guy to hook up and get to POST.

  4. Local repair guy says motherboard is fried (he could not get it to POST), bought new motherboard (the ASUS).

  5. Local guy still can't get it to POST.

  6. One month later, local guy says PSU is bad (this being the 600W that I had just bought); get computer back from local guy.

  7. Find out I have a Tiger Direct store ~25 minutes away.

  8. Go to Tiger Direct, pick out new power supply (700W), get Tiger Direct to install new PSU and make sure the PC boots.

  9. Tiger Direct says they could get the PC to boot to windows successfully, but a stick of RAM was faulty so I bought a new 4GB stick of ram (total of 6GB now).

  10. Bring PC home; it boots up. I install the new Radeon drivers and uninstall the NVIDIA drivers. While browsing the net (~30 minutes after hooking PC up), monitor suddenly goes black and I get "No Signal"; I do a hard shutdown of the computer and will only get "No Signal" to the monitor.

  11. Trying the old graphics card, everything works fine. Zero problems other than using a poor graphics card

The PSU and motherboard are brand new, motherboard being around 20 days old and the PSU being bought as of last Sunday. The CPU and Gfx Card I've had for almost two months now and have been trying unsuccessfully to get them to work since then. As of right now the new CPu works fine but I am using the old graphics card.


I'm looking at the chain of events here, but it's a little fuzzy as to what happened and when.


Ok. Looking at your detailed chain of events. The new video card was in contact and/or in use with...

  • old motherboard
  • 300 watt power supply
  • 600 watt power supply (bad?)
  • new motherboard
  • 700 watt power supply

It was out of your hands in the hands of the local computer repair guy for a month. Not saying anything bad happened... but I do question his diagnostic skills. Yes, it is possible that things went bad as were described... but if the 600 watt power supply was bad from the get-go, you wouldn't have needed a new motherboard... and he should have tested the power supply with a bona-fide PSU tester before you bought a new motherboard. At any rate... just putting that out there.

Underpowering a video card can cause issues. Depending on how cheap the power supply was that you initially used, you could have blown a solid capacitor on the video card, or a capacitor inside the power supply, or yes... even on the motherboard. If you attempted to power the system with the weak power supply more than once, this chance is increased.

But wait... the Video card worked for 30 minutes at the end there... that's significant, right?

I've seen motherboards with obviously blown caps boot and function. I remember one that would not boot on a restart. The system had to be turned off completely, and turned back on if you wanted it to boot. I remember another that would randomly hang at the bios. Sometimes it would boot, sometimes it wouldn't. In both those cases, replacing the blown caps made the issues go away. There were others. In that second example, the random bootability, eventually, it stopped booting... which means that once the caps were blown, even though nothing else went or was bad in the system, the problem will get worse.

Blown capacitors are one of the largest power related issues that computer owners deal with, whether they realize it or not. If you trip the breaker in the room one too many times, you might end up dealing with blown capacitors even if you have a surge protector. And yes, underpowering a system with a PSU that is too small for the components can also cause issues.

It is possible that you are looking at this sequence then. Use 300 watt supply --> damage video card --> use 600 watt power supply --> video card damages PSU --> use new, better quality 700 PSU --> video card finishes dying.

You are most likely outside the 30 day return... but not outside the warranty period with Sapphire. RMA the video card with them. And, I'm still serious, you need to have your PSU's tested. I don't mean that they should be connected to another computer. I mean someone needs to connect a PSU tester to them. Everything that has touched the video card should be looked at. Why? If the video card was damaged initially, who knows what cascade of damage was passed on when it was connected to other motherboards and components. Have the 600 watt one tested too, if you didn't throw it away. Hell... you owned it for less than 30 days and for all you know, it could have been shipped from the factory bad and THAT was what killed the video card.

  • Sorry about that, it is a bit confusing :) I updated the original post with a timeline of events. The PSU I'm using right now I bought last Sunday and has only ever been used with the new board, not the old one that (purportedly) blew. – Wayne Molina Mar 19 '13 at 22:28

Try using a linux live cd and see if the graphics card works using linux. If that doesnt work, your GPU is probably fried and should be returned. Also try with a different computer and a linux live cd.

  • I can't get any signal to the monitor at all, just a black screen, yellow monitor light and "No Signal" briefly after I power on the pc. Also I can't test with another computer since my other one doesn't have a powerful enough power supply to run the card. I thought it might have overheated but after the first time it will not get recognized at all by the monitor although all the fans on the card spin. – Wayne Molina Mar 20 '13 at 15:43

I've built a few PCs from scratch and run into this problem fairly often.

I find the problem is usually that the graphics card is trying to send a signal to the display out. I'd try switching between the DVI/DisplayPort/HDMI ports on the card and see if any of them produce a signal for you.

It's a simple fix and I have no idea why it happens but it's worked for me on multiple occasions.

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