No more video signal on MSI Z97-G45 rig (NOT solved)

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#1
Edit: it was my crummy PSU. Replaced it with a nicer one and my PC is working beautifully again.

Edit 2: Well, after installing a new PSU, the PC lasted for maybe a day before losing the video signal again. Now looking for another fix.

Original post:

I booted up my PC this morning - same as I always have for the past several months that I've had it - and only after a couple minutes of use, my monitors suddenly started flickering once or twice before completely turning off. The PC itself still appeared to be running.

Puzzled, I switched my computer off (can't remember if I had to hard-switch it off or if I was able to do a soft shutdown, sorry) and I turned it back on again, hoping maybe it was just a fluke. Still no video signal. Grabbed a flashlight and took a closer look at the GTX 980 inside my computer. One of the fans wasn't spinning. The other fan appeared to be working, but the fan speed was oddly fluctuating up and down. Weird. So maybe something was wrong with the GPU.

I opened the case, dusted everything out, re-seated the GPU, and also reset the CMOS for good measure. Turned it back on and still no video.

The 980 is definitely toast, right? I set aside the GTX 980, clear the CMOS one more time, and try turning on the PC again, this time using the integrated graphics on the motherboard. Nope... still the exact same behavior, even with integrated graphics.

So regardless of whether I use a dedicated GPU, or the integrated GPU, I get no video signal. There must be a deeper problem somewhere. I started slowly unplugging different things both inside and outside the case - any unnecessary USB peripherals, USB connectors, audio connectors... I even unplugged all of my SATA drives.

I tried booting the computer back up multiple times during this process (clearing the CMOS almost every time). So far there's been one occasion when I did manage to get a BIOS setup screen very briefly before the monitor turned back off again. Didn't really give me any time to actually do anything.

So maybe there's an electrical short somewhere in my computer, some kind of foreign object or debris that's causing the problem? But it's so strange that it would just randomly happen to my PC in the middle of use. Regardless, I took apart almost my entire PC (bar the CPU cooler) used my electric duster to clean everything off, and carefully-reassembled everything. Pressed the power switch and... still no video.

I don't know what to do. At this point I think it might be a motherboard problem, but I don't know for sure. My CPU (an i7-4790k) was overclocked to 4.6Ghz at 1.20v, which I know is the outer-limit of OC for that particular chip, but it's always been completely stable and rarely goes into the 70's temperature wise, unless playing demanding video games. Everything else in the system was running at stock.

Any advice on what to do next would be appreciated. Thanks in advance.

Specs:

i7-4790k @ 4.6Ghz
MSI Z97-G45 mobo
Corsair Vengeance 16GB DDR3 1600Mhz RAM
MSI GTX 980 GAMING 4G video card
Samsung 840 EVO 120GB SSD
WD Black 4TB HD
Corsair CX750M PSU
Corsair H80i cooler
 
Last edited:

ArisVer

Golden Member
Mar 6, 2011
1,192
0
76
#2
Do you have a second computer and monitor?

If you have: test the monitor on different computer. And test the graphics card on different computer.
 

Ketchup

Elite Member
Sep 1, 2002
14,372
16
106
#3
Unplug everything not necessay for the computer to boot (extra RAM, drives, USB, etc) and see if things change.

If that makes no diff, I am guessing the power supply first.

Are the fans plugged into the board working? If they are not working, but the ones plugged straight into the PS are, could mean a board problem.

Keep us updated.
 

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#4
The PC started exhibiting some different, more bizarre behavior this morning. In addition to no video signal, the PC also appeared to be stuck in a boot-loop. The fans spun up and the LEDs turned on, stayed that way for a few seconds, then turned back off. A couple seconds later, everything turned back on, and then back off again. I was only able to reproduce this behavior a couple times before it went back to its previous state. Very erratic.

Do you have a second computer and monitor?

If you have: test the monitor on different computer. And test the graphics card on different computer.
I forgot to mention that I am using a dual monitor setup with this PC. Would be very strange (but very unfortunate) if both of them stopped working at the same time. Pretty sure they're not the problem. I can power both of them on, make them scan for inputs, and manipulate the built-in menus. I've also tried different combinations of them (both, or one, or the other) plugged into the motherboard, using both DVI and HDMI cables. Neither are getting any video. I think we can rule that out.

Unplug everything not necessay for the computer to boot (extra RAM, drives, USB, etc) and see if things change.

If that makes no diff, I am guessing the power supply first.
The only things I have plugged in at the moment:

External

Main power cable
DVI video cable

Internal

24pin motherboard power
8pin CPU power
1 stick of RAM (in slot closest to CPU)
Front-panel power switch, reset switch, and LEDs
Fans

That's it. All of my audio cables, network cables, and USB peripherals are disconnected. Inside the case, the audio and USB pins are disconnected, the SATA drives are disconnected, and my video card isn't in there either. Doesn't seem to make any difference.

Are the fans plugged into the board working? If they are not working, but the ones plugged straight into the PS are, could mean a board problem.
The chassis fans plugged into the motherboard are working fine.

I'm definitely beginning to suspect a PSU problem, especially with the weird boot-looping that was happening earlier this morning. My power supply may be on the fritz.

If that's the case, Corsair does have a respectable RMA service if I recall correctly, so I will probably go that route. If anyone has any additional insight it would be much appreciated. Thanks.
 

daveybrat

Super Moderator
Super Moderator
Jan 31, 2000
4,950
45
126
#5
Corsair CX750M PSU
It's funny but i JUST replaced that exact same power supply for a customer 2 days ago. His system was exhibiting strange symptoms with a GTX 970 card. Replaced the power supply with an EVGA 600Watt and it works great.
 

Ketchup

Elite Member
Sep 1, 2002
14,372
16
106
#6
I agree, power supply is the best place to start.
 

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#7
Problem solved, it was definitely the PSU. :) I went ahead and bought a new Rosewill PSU (one of the Capstone units, mind you; arguably better than Corsair's low-end units) and it just arrived today (thanks Amazon Prime). Installed it and my PC is back up and running beautifully.

Since the old Corsair PSU is still under warranty I might as well still RMA it. I'm keeping the Capstone though, the higher efficiency and complete lack of coil whine is pretty great.

Thanks everyone!
 

Ketchup

Elite Member
Sep 1, 2002
14,372
16
106
#8
Great news! It is hard to beat Amazon Prime.
 

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#9
Well... I spoke too soon. My PC worked for all of about a day. When I got home from work today, and flipped the PC back on, it lasted for a few seconds before the monitors flickered off and the computer hard-froze. I've tried rebooting it a couple times, and I simply cannot get a video signal. :( It's the exact same problem all over again.

Agh. I hope the power supply isn't dead again, especially considering I literally just bought it. Maybe there's another component somewhere in my setup that's decided it's going to fry every PSU I connect to it?

One weird thing to note: When I press the power button, the computer sounds like it's POSTing. Not only do the LEDs turn on and the fans spin up, but after a few seconds I can hear the fans "settling down" to their regular speeds controlled by the BIOS. If that makes any sense.

Any advice would be appreciated. I'll look at it some more tonight but I really don't want to have to go through this whole process again of unplugging everything and trying to deduce the culprit. Sounds like I might have to though.
 

Ketchup

Elite Member
Sep 1, 2002
14,372
16
106
#10
We have been through a good many things already, so I will try not to repeat :)

You said it seems to POST. Can you tell if it is accessing the boot drive?

Have you tried removing the video card and trying the onboard video again?

Have you tried a different video cable?
 

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#11
Have you tried a different video cable?
Yes. Although keep in mind there are already two monitors hooked up anyway, so unless both cables just happened to fail at the same time... :p (But yeah, I did swap out one of the cables just for good measure).

Have you tried removing the video card and trying the onboard video again?
Yeah. I've removed the video card, cleared the CMOS and am currently attempting to boot the computer with the integrated graphics. Still no video signal whatsoever.

You said it seems to POST. Can you tell if it is accessing the boot drive?
I suspect it's not. The disk access LED isn't blinking/lighting up. I would try listening, but the boot drive is an SSD so it wouldn't be making any noise anyway.

Basically, I press the power button, the fans spin up, the LEDs on the motherboard (and the closed-loop water cooler) light up, you can hear the optical drive initializing, and after a couple seconds you can hear the CPU fans fluctuate/lower in speed. But no video.

I believe the system is definitely freezing/hanging internally. If it was booting into Windows without any problems, I'd be able to simply tap the power button (which is set to "Shutdown" in Windows power options) and the system would do a soft-shutdown after a couple seconds. Such is not the case however. I have to physically hold down the power button for a moment and make the system hard-shutdown. And yeah, like I said, the disk access LED isn't blinking so I don't think it's actually booting into Windows.

I'm not really even sure that the system is actually getting through POST. I only suspect it is because of how I can hear the CPU fans going full blast at first and then automatically changing speeds a few seconds in, the same way it usually does when booting up. So it sounds like *something* is happening in there. But I guess it doesn't get very far before hard freezing.
 

Ketchup

Elite Member
Sep 1, 2002
14,372
16
106
#12
The POST beep on a successful boot occurrs after the spin down, so I agree the POST may not be finishing if you don't have a speaker attached or on the board to verify. If you are encountering the exact same thing as before the power supply was replaces, I think you either got a bad power supply, or have a short somewhere in the case. Being able to hear the POST beeo can be very helpful in situations like this.
 

Dankk

Diamond Member
Jul 7, 2008
5,539
5
81
#13
I really wish my motherboard had an internal speaker output, or a built-in seven-segment display for debugging. Would be really helpful right now. Unfortunately it has neither. :\
 
Jul 13, 2015
89
0
0
www.indiegogo.com
#14
It sounds to me like not enough wattage. You can go to pcpartpciker and enter those parts and it should tally them up for you and show you a total watt estimate.
 
Jun 22, 2018
1
0
1
#15
I really wish my motherboard had an internal speaker output, or a built-in seven-segment display for debugging. Would be really helpful right now. Unfortunately it has neither. :\
Hi!!
I'm sorry to resurrect this topic, but I have the same motherboard and I'm going through the same problem. I was beginning to think it was the PSU until I found this topic.
Were you able to solve the problem?
 

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