My computer will turn on but will not send a signal to the monitor.
September 26, 2016 12:28 PM   Subscribe

What could be the problem? What should I do?

A while back I turned on my computer. I hear the hard drive spinning up, the fan, two beeps. After a few seconds a little box comes on the monitor saying "No Signal" and the monitor goes to sleep. I check the HDMI connection on both ends. Seems good. I pull the HDMI cable out of the desktop computer and plug it into my laptop. The laptop and monitor work fine together. I unplug everything, open the side panel of the tower, and poke around, wiggle the cables, make sure the graphics card seems to be seated properly. Everything seems OK. I close it back up and plug it all in and try again. Same result: No Signal. Well, I need something on the hard drive, so I pull the drive out, put it in an enclosure, and access my files via my laptop with no problem. Hard drive seems fine.

A while later, I take the tower into a PC repair shop. The guy plugs it into power and attaches it to a monitor. Power on and the computer starts to boot up. The logo of the motherboard appears on the monitor. Text on the monitor says PCI failure [no hard drive], no bootable media, attach bootable media and retry. I notice he is not using a HDMI cable. He tries the same routine with an HDMI cable with the same results. The computer seems to be able to send output to the monitor. He opens up the tower, pokes around, finds nothing amiss.

I return home, plug the tower into my monitor and turn it on. I get the same result as back at the repair shop. OK weird, I guess it works. I power off and go get my hard drive, plug it and everything else back in, and boot up again: No Signal. I attach the laptop to the monitor: works fine. I get a brand new HDMI cable and connect the tower back to my monitor: No Signal. I carry the the tower over to my TV and plug it in with the HDMI cable that is currently attached to my Roku: No Signal. I open it up and take the hard drive out and try again with the TV: No Signal. I take it over to the monitor and try with the new HDMI cable: No Signal.

Not sure what to do. It is mid-tier (lower mid-tier?) computer from 2011, specs below. I would be willing to pay $1-200 for a new graphics card, but only if I was fairly sure it would fix the problem. Could it be the motherboard? It doesn't seem like the motherboard has onboard graphics. Can anyone confirm? I have the skills to replace the graphics card if I can determine which one to by, but I replaced a motherboard once before and it was really stressful trying to seat everything without using too much force and getting everything to fit in the case. I barely kept myself from throwing the whole mess out the window but it got done. Taking it back to the shop is also a pain for unrelated logistics reasons, but maybe they could test the graphics card and motherboard more thoroughly? I have the laptop, so I am not desperate for a second computer, but I prefer the desktop for 1) gaming and 2) when I need to work for long periods of time and can use the full keyboard, widescreen monitor for comparing documents, desk chair for comfort, etc. Maybe I should just wait until I can afford a new one? I hate to throw it out or even donate it if it is a simple fix as the specs are fine for my needs.

Processor: AMD Athlon II X4 640
Motherboard: Gigabyte GA-770T
Storage: 2x1-TB Hitachi 7200 RPM drives
Video Card: ATI Radeon HD 5770
Memory: 2x2-GB DDR3-1600 RAM modules
Operating System: Windows 7
posted by nequalsone to Computers & Internet (10 answers total)
When this happened to me, it was the motherboard. I didn't discover that until after replacing the power supply, though. For what it's worth, that motherboard was also a Gigabyte. (GA-870A, which I think makes it the model after yours)

My first suggestion is to replace the video card. Just get a cheap basic one for testing.
posted by INFJ at 12:38 PM on September 26, 2016 [1 favorite]

Are you sure it's actually booting when you're getting no graphics on the screen? There's not a solid initial way to test this, but listening to the distinctive clicking of your physical hard drive might be a good sanity check. My first thought would be to connect it to the network, let it boot, and then see if I could access that computer via Remote Desktop in order to check out the system log.

My initial guesses would be that something is screwy with the graphics card or power supply. If it's the latter, then connecting the hard drives would have been enough of a power sink to stop the system from booting.
posted by mikeh at 12:39 PM on September 26, 2016

Could it be the motherboard? It doesn't seem like the motherboard has onboard graphics.

If it does, there should be a video connector or two on the motherboard I/O panel. What connector you'll get depends on the motherboard, but it might just be HDMI. IME the system will just use whichever video device has a monitor plugged in -- if it's plugged into onboard video it won't use the video card.

One possibility is that HDCP (HDMI copy protection) is failing with your particular combination of devices. Did you try DVI instead of HDMI, maybe? Or VGA?

Replacing a video card should be much easier than replacing the motherboard.
posted by neckro23 at 12:40 PM on September 26, 2016

I checked the back panel on that particular motherboard, no VGA (or DVI, or anything else) out.

for reference

echoing mikeh's post and I'd be inclined personally to think it's the power supply, especially with the weird behaviour when you're connecting two hard drives and then getting failure.
posted by majuju at 12:44 PM on September 26, 2016

Ah, nevermind then.

PSU is a likely culprit, yeah. That's usually the first thing PC builders skimp on.
posted by neckro23 at 12:48 PM on September 26, 2016

So, the power supply was replaced maybe half way into the life of the computer with a higher output and better brand model. When the original power supply failed, the PC wouldn't turn on at all. The repair guy (same guy) said the one that came with it was indeed not great, but I would hope that the new power supply would not fail so quickly. But of course it could I guess... (Also, despite the purchase specs above, I am only running it with one hard drive in, so there is somewhat lower power consumption than maybe it would seem.)

When I boot with the hard drive in, I can hear the hard drive continuing to spin even after the monitor goes to sleep. I punched return on the keyboard and it started accessing files, so I assumed it was on the "Your computer didn't shutdown properly. Do you want to start in safe mode?" screen. Relevant?

If it is an HDCP thing, it is an HDCP thing related to the tower because I tried with 3 different HDMI cables and two different monitors and all configurations worked with my laptop but not the desktop. Also, it worked with both HDMI at the repair shop. So that boils down to either graphics card or motherboard, right? I asked the guy if the HDMI jack on the graphics card could be faulty but he dismissed that idea pretty confidently. I will see if I can dig up a DVI cable though. That's a simple thing to test.
posted by nequalsone at 1:06 PM on September 26, 2016

I think I may have disabled remote access but if I can get in where would I find the system log and what would I look for when I found it?
posted by nequalsone at 1:16 PM on September 26, 2016

A couple things to try:

1). Look at the capacitors on the motherboard. Run your finger on top of them. Do they feel indented or bulging? If bulging or leaking, time to replace motherboard. Was there a storm or power issues?

2). How many sticks of RAM do you have? If multiple can you take out all but one? And try again. Switch them out and put in different slots.

As a tech. I've seen a power spike hit a motherboard and blow some capacitors that cause same symptoms as well as bad RAM.
posted by bleucube at 1:42 PM on September 26, 2016

Simple solution - buy (or borrow) a video card that you can return. Install and test. If it works, you can keep the card and if it doesn't, you can return it and move on to the next step in troubleshooting.

The AMD R7 360 is a good card for $100 and the Nvidia GTX 950 is good for $150.
posted by cnc at 3:58 PM on September 26, 2016

You could take both computer and monitor to the fixit shop.
posted by SemiSalt at 4:22 PM on September 26, 2016

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