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Weird Monitor Problem

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Jan 22, 2020
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I have a very very strange problem and I really need your ideas.. My monitor always blinks for about 1 second whenever I turn off/on my light. Fearing this may cause harm to my newly built Ryzen system, I decided to buy a top quality line interactive UPS from Schneider Electric. I connect everything including speakers and monitors to ups. But the problem goes on..
In the end, I isolated the ups completely, unplug from the mains, means there is absolutely no connection with outside world, but the problem still exist.. I turn on/off the light, and monitor blinks even there is no electrical connection..
What are your ideas? What can I do? And most importantly, does it harm my pc??
 
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Sound like EMI/RFI (electromagnet/radio frequency interference). I would start by making sure the video cable between the computer and monitor is securely fastened. If it is, then replace it with a different cable.

What kind of light is it? Florescent lights are notorious for generating RFI. Make sure the light is securely tight in its socket - better yet, replace the bulb. It could also be loose wiring in the switch or fixture. This should be checked as that could pose a fire hazard.

BTW, nice troubleshooting technique, isolating everything by having it run only on the UPS batteries! :)

***

As a side note, since the problem is there with the speaker connected to the UPS too, I recommend you move the speakers' power connector off of the battery side of the UPS. Beside the fact you don't need audio during a power outage, audio amplifiers can draw a lot of power and drastically reduce your battery run time.
 
Joined
Jan 22, 2020
Messages
76 (0.19/day)
Location
Türkiye
System Name Asus Tuf
Processor AMD Ryzen 3900X
Motherboard Asus Tuf x570 Plus Wifi
Memory 16 GB
Video Card(s) MSI 1660
Storage 500 GB WD nvme + 2 TB Seagate HDD
Display(s) 21,5" AOC Full HD
Case Asus Tuf
Audio Device(s) Altec Lansing
Power Supply Seasonic
Mouse Logitech
Keyboard Microsoft
Software Windows10 LTSC 64 bit
Most probably it is about Emi yes, but how could a stupid tiny electrical line could emit that kind of radiation? I'm thinking about wrapping the DVI cable with aluminium foil to protect any interference. will update the result.
 
Joined
Jul 25, 2006
Messages
8,190 (1.54/day)
Location
Nebraska, USA
System Name Brightworks Systems BWS-6 E-IV
Processor Intel Core i5-6600 @ 3.9GHz
Motherboard Gigabyte GA-Z170-HD3 Rev 1.0
Cooling Quality case, 2 x Fractal Design 140mm fans, stock CPU HSF
Memory 16GB (2 x 8GB) DDR4 3000 Corsair Vengeance
Video Card(s) EVGA GEForce GTX 1050Ti 4Gb GDDR5
Storage Samsung 850 Pro 256GB SSD, Samsung 860 Evo 500GB SSD
Display(s) Samsung S24E650BW LED x 2
Case Fractal Design Define R4
Power Supply EVGA Supernova 550W G2 Gold
Mouse Microsoft Wireless 5000
Keyboard Microsoft Wireless Comfort 5050
Software W10 Pro 64-bit
If wrapping the cable with foil helps, you need to buy a new cable as that cable (or one of its connectors) is clearly bad.
 
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