Desktop screen turns off randomly and then turns on again af

Dell S2240m black 21.5 7ms (gtg) widescr...
December 4, 2016 at 00:35:49
Specs: Windows 10, Intel Core i3/8GB RAM
I have a NVIDIA GT 620, ASUS H61M-CS motherboard, Inter Core i3 3240, Dell S2240M monitor with Windows 10 installed.
The monitor itself turns off (doesn't go into standby mode) and then turns on again with the Dell logo showing up, behaving exactly like when screen starts up after power is supplied. This hasn't happened whenever I stayed on a particular screen for a while, for example when writing this, or watching a video. I've noticed it happens more if there's activity, for example, when I switch tabs on my browser, or scroll down when reading something. I think the power is somehow disconnected for some 20-30 seconds from the monitor before coming back up.
I've no idea how to troubleshoot this; seems completely bizarre. Any ideas?

Title edit: Desktop Screen Goes Off Randomly and Turns On Again After About 20 Seconds.

message edited by RoboWarrior0714


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#1
December 4, 2016 at 01:07:25
Are you able to use the motherboards integrated graphics to rule out any hiccups with the graphics card?

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#2
December 4, 2016 at 01:27:28
Did that, and it still happens. No hiccups with the graphics card. And when the screen goes off, I don't get the hardware connection/disconnection sound either.

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#3
December 4, 2016 at 02:37:40
> The monitor itself turns off (doesn't go into standby mode) and
> then turns on again with the Dell logo showing up, behaving
> exactly like when screen starts up after power is supplied.

If the monitor turns off completely, rather than going into
standby mode, then I would expect you to have to press its
power button in order to turn it on again. Very surprising if
it comes back on all by itself. Does this monitor not have a
power button? It is normally always either on or in standby
mode as long as it is plugged in, never off?

-- Jeff, in Minneapolis


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#4
December 4, 2016 at 03:33:51
I have a Dell S2240M. Yes, it does have a power button, and pressing that doesn't help. It comes back online after 20-30 seconds. I've tried unplugging the power cable from the back in the monitor quickly as it turns off and then plugging it again, but the screen doesn't come back until those 20-30 seconds have passed. I'm thinking something's up in the adaptor in the power cable.

message edited by RoboWarrior0714


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#5
December 4, 2016 at 04:16:09
Hi Robo,

I am wondering psu.
Reason for this is certain psu connectors and/or cables are strictly for graphics supply..

How old is the PC?
Could it need the dust blowing out including from inside the psu.

I would consider carefully disconnecting/connecting each psu to mobo connector 2 or 3 times, which should clean them.

Do some googling first on what each connector supplies.
If a graphics one is very tight, it could be it is being overloaded.
.

Good Luck - Keep us posted.


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#6
December 6, 2016 at 05:10:51
My PC is one and half years old (The monitor over 3 and half-ish years old). I did blow out dust (which was a lot), but couldn't find any power connector for the PCI slot. I don't know if I'm looking correctly, but here's how my motherboard looks-https://www.asus.com/websites/global/products/kFyd5JQHKtkiATTF/line_01.jpg [ASUS H61M-CS]
The screen is going off less frequently now that I've cleared all of that dust. Btw, I've run into different kinds of problems before because of the dust.

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#7
December 6, 2016 at 11:42:52
I'm still surprised that the monitor comes back on by itself.
Once it turns off, it should stay off until you press the power
button, unless it is designed to turn on whenever it receives
a video signal, which is certainly possible but I don't recall
ever seeing such a thing. If that is the case, then likely the
problem is with the detection of the video signal by the
circuit which automatically turns the monitor on and off.
I'd think it would go to sleep rather than turn off, though.

-- Jeff, in Minneapolis


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#8
December 6, 2016 at 16:08:50
looks like your PC is restarting.
Less frequent after dusting out? Check if the CPU cooler is properly mounted. Where is this PC box located? Home, office, workshop?

message edited by sluc


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#9
December 6, 2016 at 20:14:28
The GT620 does not use a separate power connector. Power supply is unrelated unless Windows is also restarting.
The problem might be in the monitor's power cable (try a different power cable) but I doubt it, it does sound like there is an issue with the dust. Either there is still a lot of dust there still or a little bit but in a critical place and it is causing an overheating issue. Try blowing it out again or open it and blow it out that way.

You have to be a little bit crazy to keep you from going insane.


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#10
December 7, 2016 at 00:15:46
Yes, this is baffling. The PC is at my home. It doesn't go into sleep mode, i.e., I don't see the yellow standby light on the monitor.
If it were a problem with video detection, then why would the monitor go off instead of the monitor going into standby mode? The monitor going off (i.e. losing power) has to be power related. And since this happens for a specific time interval, I think its some circuit that deliberately cuts it off (maybe because it overheats?)
And it's less frequent after the initial dust blowing, which could mean less overheating so that circuit doesn't switch off.
I'm going to check the fans and blow out the dust again.

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#11
December 10, 2016 at 02:23:51
Hi Robo,
to isolate where the fault lies, are you able to try the Monitor on another PC?
(or a different Monitor on your PC)

If so and the faulty Monitor fails, the problem is with the Monitor
Suspect the Dell logo is coming from the Monitor.
Could be its power cable - as suggested above.
If rewireable Mains Plug - check its connections - and tightness of (if present) fuse contacts.

If you go inside the Monitor, be VERY VERY careful, as voltages that kill remain after switching OFF and/or disconnecting.

Good Luck - Keep us posted.

message edited by Mike Newcomb


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#12
December 17, 2016 at 06:09:16
I've blown all the dusk I could. Cleaned the board, the graphic card, RAM, the PSU connections, fans, the PSU (by removing the PSU cover). It still happens.
But I've yet to try another power cable for the monitor or any temporary monitor.

message edited by RoboWarrior0714


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#13
December 18, 2016 at 05:34:40
I would coordinate with a friend if necessary and test your monitor on another computer and another monitor and another monitor cable (first one, then the other, then both). This should nail down if the problem originates in the computer, the monitor, or the cable. If anything defective is still under warranty, then bring/send back for replacement.

You have to be a little bit crazy to keep you from going insane.


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