PC "no signal" upon booting?

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woodson

187 posts

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# 250677 21-May-2019 12:05

Have an issue where a PC is powered on, but no signal to the monitor. Problem is not consistent though – after unplugging the power cord for a while, sometimes it works.

Specs. are a 2014/15 Pentium G, 4GB DDR 3, Asus H81M+ mobo, Corsair 430 watt PSU.

Troubleshooting so far:

Checked seating of all cables and RAM.
Tried swapping RAM to different slot
Power cycled
Tried brand new PSU
Tested RAM with MemTest86
Reset CMOS by removing battery.
Tried different monitor cables (DVI and VGA - have not yet tested with an HDMI connection)
Ran Crystal Disk on the HDD - no problems

Funny thing is, it's fine when just restarting (as opposed to powering down completely and starting up again). But if I try to boot from scratch twice in a row, I get 'no signal'the second time. Only way to get it working again is to power down and unplug for a few minutes.

Any advice is gratefully received at this point. Pulling my hair out!

boland

248 posts

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# 2242287 21-May-2019 12:24

Maybe far fatched, did you try a different monitor?

Is the PC booting, or do you hear beeps indicating a boot error?

Did you clean the case, removing dust inside?

woodson

187 posts

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+1 received by user: 5

# 2242299 21-May-2019 12:45

Have tried two monitors, but have yet to try one with hdmi, just in case (long shot)

There are no beeps upon power on - not sure the motherboard has a speaker?

The case didn't have much in the way of dust in it.

tyronne

14 posts

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# 2242466 21-May-2019 16:48

One person supports this post

Diagnosed a PC with the exact same symptoms. Thought it was a overheat situation due to "cooling off" allows a boot. The issue ended up being standoffs were not installed causing a short. Luckily didn't have to bust out the multimeter. Worth checking.

woodson

187 posts

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# 2242523 21-May-2019 17:36

Yeah I was thinking the next step might be to take the mobo out of the case. The machine has been running fine for 4 years, so seems unlikely, but worth a shot.

Have also added an old GPU, but the intermittent issue still persists.

Am now looking creating even logs for when it boots successfully, saving and clearing an then creating another log for times when it doesn't boot, to see if anything shows up. There's a driver error of some sort that came up in the last log, around the time of a failed boot, or rather a 'no signal' boot. Will see what Google has to say.

sqishy

130 posts

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# 2242531 21-May-2019 17:51

One person supports this post

Had a few like this, try loading new bios firmware, I assume battery is still at 3V?

woodson

187 posts

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+1 received by user: 5

# 2242534 21-May-2019 18:03

I was just looking at BIOS updates on the motherboard drivers page - there was only one update after I built the machine, so I guess that's worth an install. I see there was also a new Intel Graphics Accelerator Driver released for the board a couple of years after I built the machine, so will try that as well.

woodson

187 posts

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+1 received by user: 5

# 2242535 21-May-2019 18:06

sqishy:

Had a few like this, try loading new bios firmware, I assume battery is still at 3V?

Do you mean the CMOS battery? I have no idea if it's still at 3V. I think I have a couple of fresh batteries lying about (it's a standard CR2032 type) - is it worth replacing?

sqishy

130 posts

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# 2242597 21-May-2019 19:22

One person supports this post

The CR battery is only used when you pull power of the PSU at the back, normally if CMOS settings drop on boot you will get a message or find it restores to default.

$2 shops sell these very cheap. Re-loading the BIOS firmware often fixes a corruption somewhere so good to try that in any case. I'll have a think about what else to try.

Also how may RAM slices do you have, sometime faulty RAM stops boot at start, if you have more than 1 then try 1 RAM slice at a time etc.

woodson

187 posts

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# 2242755 21-May-2019 21:50

Only one stick of RAM. Ran Memtest and it passed without errors.

sqishy

130 posts

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+1 received by user: 47

# 2242758 21-May-2019 22:01

woodson: Only one stick of RAM. Ran Memtest and it passed without errors.

Other thing to try is if it doesn't start then where the multi-colored cable from the PSU goes into the Mobo try to short with a small wire or paper clip the Green & Black for 1-2 seconds and release and see if it starts.

freitasm

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# 2242759 21-May-2019 22:06

And no GPU (assuming by your description it has on board video at least)?

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Aredwood

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# 2242760 21-May-2019 22:17

Next time it fails to start. Try removing all of the ram, then turn it on. It should beep continuously without any ram. Switch off, reinstall ram, retest.

My computer would fail to start sometimes as well. And the above was the only thing I found that would get it working.

Also check the voltage on the grey wire in the main ATX power connector. Should be 5V. If 0V it means that the PSU has detected that the voltages are incorrect. And the computer wont boot.

1101

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# 2242905 22-May-2019 09:09

Aredwood: Next time it fails to start. Try removing all of the ram, then turn it on. It should beep continuously without any ram. Switch off, reinstall ram, retest.

My computer would fail to start sometimes as well. And the above was the only thing I found that would get it working.

My home PC does exactly the same thing. When it fails to Boot (actually fails to POST), I move the RAM to another slot & it fixes it. Then the next time I move it back to the original slot & it fixes it. :-)

woodson

187 posts

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# 2242964 22-May-2019 10:33

Well, it seems the problem is resolved, though I'm not 100% what fixed it. Late last night, decided to have another crack at it. Decided to update the onboard VGA drivers (although at that point I was using an old 5670 GPU for video as that worked intermittently). I also flashed the BIOS to the newest version. Et voila, all was well. Left it running overnight, tried a few time this morning, all was good. Tried switching back to onboard video...and same problem. Odd! So, since then I've been powering up and down with the GPU connected and no problems at all. I feel like, based on some comments on here, and other things I've read, that the BIOS update probably helped, but that still doesn't explain why the onboard video still has the problem.

Oh well, all seems ok now. Massive thanks to all of your for your advice, really appreciate it. I'll definitely be saving this thread in case I need tips for any future issues with similar symptoms. :)