Computer powers on, but monitors get no signal

ATI radeon 4800 GPU, Intel Core 2 Duo CPU, 8GB ram, Gigabyte mobo, 2 1280x1024 monitors I've been having problems with the computer crashing pretty often when I start playing games. When I say 'crash', I mean that my two monitors go dark, and sound gets glitchy a few seconds later, but remains powered on. I was able to get around this for a while by having a (real) fan blowing next to my open case, and when that started failing, also underclocking the GPU (with the software included). Last night, when the computer went to sleep, and I tried to wake it up later on, the CPU/lights/whatever turned on, but the monitors stayed off. I turned off the computer, tried turning it on multiple times over a long period of time, and it still wouldn't work. Same thing this morning. I boot from CD because I kind of ****** up my partitions a while back and have to detect my operating systems with a program, but that doesn't seem to be the problem since the CD does start spinning shortly after I power on. I've ordered a new Video Card, as I imagine that's the problem, but I just wanted to post this here to see if anyone thinks the problem could be something else. Thanks!

Whenever I get strange hardware issues, I always want to verify I got good power before I start committing money to other parts. So if me, I would swap in a known good PSU and see what happens. Also note that graphics are often the most power hungry devices in a computer, so it is common to need a bigger PSU when replacing the card. The fact a desk fan used to help but no longer does is not a good sign. It could indicate something that was failing, has now failed completely - and hopefully, it is not the motherboard.

Hi Zedd, After reading about the fan issue, I'm just wondering if you have been doing a bit of overclocking? Cheers, Lee

Hi Zedd,

After reading about the fan issue, I'm just wondering if you have been doing a bit of overclocking?

Cheers,
Lee

Not really. The previous owner did, but the most I did was bump the CPU up from 3.16 to 3.4, and that was early on.

Whenever I get strange hardware issues, I always want to verify I got good power before I start committing money to other parts. So if me, I would swap in a known good PSU and see what happens.

Also note that graphics are often the most power hungry devices in a computer, so it is common to need a bigger PSU when replacing the card.

The fact a desk fan used to help but no longer does is not a good sign. It could indicate something that was failing, has now failed completely - and hopefully, it is not the motherboard.

I don't have another Power Supply, but you may have a point. In the last week or so before its death, my computer would occasionally glitch up the screen for a split second, as if the voltage changes shorted out the video card for a split second, every few minutes. I'll look into it if the new Video Card doesn't help. If it's the mobo's fault, well… carp**.

If the PC has previously been overclocked and the PSU originally came with the PC (these PSU's are mostly poor quality), it might be a good idea to buy a quality PSU with an 80+ rating. No need to go higher than 550-650w. Next time you upgrade your case, replace it with the 80+, or if it's a second-hand PC, swap over the PSU's. Apparently, cheap PSU's loose about 20% of their power after a couple of years and are not very stable. Good quality PSU's are like good quality leather bicycle seats. Always hold onto both Most hardware nowadays is much more power efficient than it used to be. My 1GB - 9800GT video card doesn't even need it's own power supply, just slots into the mobo, so ignore all the rubbish you hear on many sites about needing an 800 -1000w PSU for gaming or future proofing your rig. I'm not saying your PSU is causing your present problems (though it might be), I was just pointing out a good option. Cheers, Lee

If the PC has previously been overclocked and the PSU originally came with the PC (these PSU's are mostly poor quality), it might be a good idea to buy a quality PSU with an 80+ rating. No need to go higher than 550-650w. Next time you upgrade your case, replace it with the 80+, or if it's a second-hand PC, swap over the PSU's. Apparently, cheap PSU's loose about 20% of their power after a couple of years and are not very stable.

Good quality PSU's are like good quality leather bicycle seats. Always hold onto both

Most hardware nowadays is much more power efficient than it used to be. My 1GB - 9800GT video card doesn't even need it's own power supply, just slots into the mobo, so ignore all the rubbish you hear on many sites about needing an 800 -1000w PSU for gaming or future proofing your rig.

I'm not saying your PSU is causing your present problems (though it might be), I was just pointing out a good option.

Cheers,
Lee

I'm not familiar with PSU's, but the one I have now is a Corsair VX550w. The rig was custom built, or so I was told, so I doubt that the power supply is bad. Do you know anything about it?

I'm not familiar with PSU's, but the one I have now is a Corsair VX550w. The rig was custom built, or so I was told, so I doubt that the power supply is bad. Do you know anything about it? I have a Corsair too (there made by Seasonic) and as far as PSU's go, well you would be hard pressed to find anything better. A 550w would easily power your PC, even if you had twin video cards. Corsairs are all 80+ Gold Standard Certified (can deliver 80+% of it's power 24/7) and that means Top Shelf. I'd be looking in other directions for a problem with your PC. Your PSU would be at the very bottom of the list as a likely cause of your your PC issues. Your Video Card came out in 2008 and might be the issue depending on what games you are playing, especially if your using twin monitors and high game settings. Unlike your PSU, it was never a top shelf card and might be seriously struggling. Cheers, Lee

I have a Corsair too (there made by Seasonic)

Only some are. Some, including the 550VX the OP has, are made by Channel Well.

Even the best can have failures. While the PSU may be at the bottom of the list of possible cause, it would still be at the top of my list of things to check. I would still want to verify my PSU was good or else you may be chasing shadows all day.

Apparently, cheap PSU's loose about 20% of their power after a couple of years

All power supplies lose capacity - even the best, using the best made capacitors lose 10% or more.

I have a Corsair too (there made by Seasonic)

Only some are. Some, including the 550VX the OP has, are made by Channel Well.

Thanks for that heads-up Digerati (I should have researched it).

I knew that my Corsair HX 620W modular was made by SeaSonic, so I concluded all Corsair PSU's were.
I was unaware that Corsair had a "value" range, the VX series and that they are made by CWT. Still, after reading a review of the VX550W, they are still a very good unit and yes, it might be the cause of the Zedd's problems.

However, without a spare PSU to swap in, I didn't like to recommend testing it with a multimeter. The PSU should be taken to a Tech. to do that. so I'm thinking of other causes first, PSU last unless Zedd would like to head off to a Tech (?)

Cheers,
Lee

Bookmark this - Tom’s Hardware, Who’s Who In Power supplies: Brands, Labels, And OEMs.

As far as testing PSUs, here's my canned text on that:

To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive ripple and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

Note the required voltage tolerance ranges:

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NOTE: Disregard the -5VDC reading. It is no longer used.

Swapping in a known good supply is a tried and true method of troubleshooting used for years, even by pros. If you have access to a suitably sized, spare power supply, carefully remove the suspect supply and replace it with the known good one, and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

Note the ATX Form Factor standard does not "require" specific color coding for power supply connector wiring. It has recommendations but manufacturers often do not follow them. Sadly, many testing guides or tutorials will refer to wire color only and that can lead to improper testing.

The voltages can be checked in the BIOS Setup Menus of most motherboards but they do not reveal ripple or other anomalies either. And of course, booting into the BIOS Setup Menu requires a working PSU.

As always, before working in the interior of the computer case, take necessary ESD precautions to ensure static buildup in your body does not discharge through and destroy any sensitive devices. Unplug from the wall and touch bare metal of the case before reaching in. And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user-serviceable parts inside a power supply. If you do not have a tester or a suitable spare to swap in, take the PSU to a qualified technician for testing.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

I use a multimeter, a very high quality one with a large LCD readout. However, I always take a PSU out to test it and never test it while it is installed as that would be asking for trouble. As you probably know, there is a very simple trick to fool the PSU and power it on while it is disconnected from the motherboard. I couldn't see any point in purchasing an Ultimate PSU Tester or one the cheapie LED testers. For all intents and purposes, although not perfect, a quality multimeter is a very good PSU tester for the average Tech.

I agree with your sentiments about "comprehensive" testing.
However, having a PSU comprehensively tested is rather a mute point..It would cost more than the PSU is worth and how many PC Techs. have the required equipment? I know of none outside of a City.

Cheers,
Lee

As you probably know, there is a very simple trick to fool the PSU and power it on while it is disconnected from the motherboard. I couldn't see any point in purchasing an Ultimate PSU Tester or one the cheapie LED testers. For all intents and purposes, although not perfect, a quality multimeter is a very good PSU tester for the average Tech.

Sorry, but no. As I noted in my canned text's opening sentence, "to properly and conclusively test a power supply unit (PSU), it must be tested under various realistic loads". You can not do that with a multimeter unless the PSU is connected to the motherboard and all is up and running. Pulling the PSU out of the case to test is certainly safer but the supply has no load. A supply with no load can easily show correct voltages then fail completely under a load.

A technician - which, in my book as a technician, is someone who has been through several hundred hours of formal classroom and practical "electronics" training (2 years for me), understands circuit loading. The quality of the multimeter has nothing to do with it. Multimeters are invaluable, but it is simply the wrong tool for the job here - unless you are willing to jam the probes into the heart of the electronics and test the voltages under a realistic load. I don't recommend users do that unless they know what they are doing and have a steady hand. This loading for accuracy is the same with batteries, and car engines too. They need a "realistic" load for a proper measure.

Also, as noted before, most multimeters cannot test for ripple. So regardless, testing would be inconclusive. And yes those testers are inconclusive too. They do provide some loading, but it is not realistic and they don't measure ripple either. You need a power analyzer, scope, or a multi-meter that does test for ripple. But then again, that also requires jamming probes into the electronics - so not recommended.

Shorting the pins just signals the PSU to turn on. It supplies no load whatsoever.

A meter can conclusively tell you a PSU is bad, but it cannot tell you conclusively it is good. And with potential power issues, that's not good enough.

Many shops charge a very nominal charge to test a PSU. When you already have motherboards on a test bench, it only takes a couple minutes. The easiest way for a user is to swap in a known good supply.