Strange PC issue. Monitor flickers when opposite side electric switches are touched.

Futureized

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Feb 11, 2013
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Hi there,
Having weird issues with pc over many weeks.
Noticed monitor flickering issues when electrical switches on opposite side of wall are turned on/off
Called an experienced electrician today (after 2+hours of trying everything, he unplugged all sockets, rechecked earthing, rechecked loose connections) who finally came to conclusions that PC has issues.

I have spare working PSU which can be tested. Any other suggestions?
 

NanditaRoy

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Jun 10, 2022
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Hi there,
Having weird issues with pc over many weeks.
Noticed monitor flickering issues when electrical switches on opposite side of wall are turned on/off
Called an experienced electrician today (after 2+hours of trying everything, he unplugged all sockets, rechecked earthing, rechecked loose connections) who finally came to conclusions that PC has issues.

I have spare working PSU which can be tested. Any other suggestions?
Does the Flickering Happen With Turning on and of , with all the switches like Fan , Ac , Lights etc or does it happen with specific switch ??
For fans it can happen , because a motor has a surge current or momentary Voltage transit caused by starting current inrush when the fan is started or speed is switched. If Possible Plug the pc and the monitor to a UPS and check if the problem persist .
This is due to Electromagnetic interference or Radio Frequency Interference. which happen not only with HDMI but also with dsub component,dvi etc video/ audio interference. be it analog or digital does not matter. Also Try using a shielded HDMI or whichever display Cable You are using .
 

kiran6680

Disciple
Oct 5, 2021
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These issues can be weird. I used to have a PC, which used to resume from suspend if anything in surrounding area was switched on/off. Changed the motherboard, it did not help. Changed the PSU, it did not help. Many years later I changed the battery in the UPS, and, voila, the issue got fixed.


So yes, try the spare PSU. Try with UPS if you don't have, or without UPS if you already have it. Using a long cable, try switches of another room. All of this separately for PC, monitor, and both.
 
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enthusiast29

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Jan 15, 2021
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It's normal, monitors are sensitive to electrical disturbances such as sparks. Replace those switches if you have issue otherwise it's fine to ignore.
BTW make sure there's no loose cables on the monitor itself, that'd be dangerous and could be fatal to the monitor.
 

Futureized

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Feb 11, 2013
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Does the Flickering Happen With Turning on and of , with all the switches like Fan , Ac , Lights etc or does it happen with specific switch ??
For fans it can happen , because a motor has a surge current or momentary Voltage transit caused by starting current inrush when the fan is started or speed is switched. If Possible Plug the pc and the monitor to a UPS and check if the problem persist .
This is due to Electromagnetic interference or Radio Frequency Interference. which happen not only with HDMI but also with dsub component,dvi etc video/ audio interference. be it analog or digital does not matter. Also Try using a shielded HDMI or whichever display Cable You are using .
Specially with fan only.
Don't have ups to check though.
Monitor is connected via HDMI
Yes will give other PSU A try.
Those are 1000 and 750 watts from corsair
Test on that psu if electrician said alls well...
Ordering and trying on new power cables as well, existing cables are almost 8+ years old.
Any suggestions for 2 good power cables from Amazon?
 

roygarg

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Aug 29, 2017
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Bangalore
Does the Flickering Happen With Turning on and of , with all the switches like Fan , Ac , Lights etc or does it happen with specific switch ??
For fans it can happen , because a motor has a surge current or momentary Voltage transit caused by starting current inrush when the fan is started or speed is switched. If Possible Plug the pc and the monitor to a UPS and check if the problem persist .
This is due to Electromagnetic interference or Radio Frequency Interference. which happen not only with HDMI but also with dsub component,dvi etc video/ audio interference. be it analog or digital does not matter. Also Try using a shielded HDMI or whichever display Cable You are using .
Second this. Try it with a UPS.
 

kvn95ss

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Jun 18, 2020
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Have a similar issue with my monitor (Lenovo L series 24) but only when the generators kick in. I'm using a UPS as well. However, my brothers display (LG 22Mp68Vq ) doesn't :/
 

Emperor

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Jan 12, 2006
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Check HDMI cable (if not using same that arrive with Monitor in box), I have had issue with Generic HDMI Cable (used 3 different local brand and all 3 have same issue).

I again start using original cable that got with Monitor and no issue so far.
 

NanditaRoy

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Jun 10, 2022
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Try with a voltage stabilizer if UPS is not available .
Using a good quality shielded HDMI cable surely does help
 

Futureized

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Try with a voltage stabilizer if UPS is not available .
Using a good quality shielded HDMI cable surely does help
Hdmi cables seems new.
Came with old 2nd hand monitor.
Specially with fan only.
Don't have ups to check though.
Monitor is connected via HDMI
Yes will give other PSU A try.
Those are 1000 and 750 watts from corsair

Ordering and trying on new power cables as well, existing cables are almost 8+ years old.
Any suggestions for 2 good power cables from Amazon?
Got this cables too. My hardware is already 10+ years old. Completely unsure what can be faulty.

Gizga Essentials Laptop Power Cable Cord- 3 Pin Adapter Isi Certified(1 Meter/3.3 Feet) https://amzn.eu/d/2KP52TS
 
Last edited:

salian

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Apr 27, 2022
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Hdmi cables seems new.
Came with old 2nd hand monitor.
I don't remember exactly which cables, but if they are the flat ribbon-like HDMI cables then they are not shielded and are a bit long as well.

If you have an electrically noisy environment, the best HDMI cables for you are:

1) as short as possible for your application
2) not flat but round (twisted cables pick up less noise)
3) shielded as per the manufacturers description
4) with ferrite cores at one or both ends
 
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Futureized

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Feb 11, 2013
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I don't remember exactly which cables, but if they are the flat ribbon-like HDMI cables then they are not shielded and are a bit long as well.

If you have an electrically noisy environment, the best HDMI cables for you are:

1) as short as possible for your application
2) not flat but round (twisted cables pick up less noise)
3) shielded as per the manufacturers description
4) with ferrite cores at one or both ends
Thanks @salian .
Can you provide amazon link to purchase same.
HDMI called can be required anywhere, will go with good quality
 

salian

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Apr 27, 2022
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51QJpskwcfL._SL1200_.jpg
Something like this, short, round and with ferrite cores, should be most noise-resistant.
Couldn't find that exactly on amazon, but perhaps this or this?
 
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NanditaRoy

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Jun 10, 2022
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Can You Try Connecting Your display with a vga cable , just to rule out if the hdmi cable could be the culprit ...just ruling the possible sources one by one .
 
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