Long-term investigation of unstable input

[cybepine]

Small update:
Since I started investigating this, the transformer feeding my house has now been replaced four times.

The first three were on the same feeder. The newest transformer, which was installed in September 2026, has a Y/Zn winding and is brand new, having been manufactured in May 2026; prior to this, I had Y0 transformers.

This time, basically everything around the supply changed:
1) New transformer, around 2× closer to my house;
2) Different 35 kV substation;
3) Completely new 70 mm² line, with the last 20 m being 16 mm²;
4) Only around 5-7 houses on this new line;
5) Completely new cables and connections.

So the transformer, feeder, grounding, and upstream supply are all basically new.

And all of that changed nothing.

I also completely disconnected the house wiring and powered the PC through a separate line after the meter. I tested it both with my PE and without it. The overall problem remained.

And if there is anyone who has any ideas, I would appreciate any useful ones.

Anything related to the body, sweat, software-based, PC, BIOS, monitor, health issues, or perioperative stuff will be ignored completely.

Earlier you wrote this:

One thing that caught my attention is that several neighbors have deep water wells (around 90 meters) with submersible pumps. There are also a few houses with three-phase service and solar inverters. The electric boilers are probably irrelevant, but the water pumps operate year-round.

Could this be your source of the problems?

All of these 3 things can cause problems and it is always the best way to remove the source or add some emi suppression to these equipment.

I found this (ferrite mix 75):

https://palomar-engineers.com/ferrite-c ... p135607443

"DAVID F.
BRUCTON MILLS,
United States
Jun 27, 2025
After installing a tankless hot water heater 90% of the lights in our house flickered so badly it was almost strobe like. I tried replacing the dimmers and lights with some success but still every time you would turn on the hot water the lights would flicker. I installed these items on the Romex going to the tankless heater as well as the individual lines inside tankless heater housing and have all the eliminated flickering. Great product great support staff thank you for all the help David Friend"

[astroasis]

Have you guys tried moving your setup further away from your wall outlet?

[fa1kk]

One thing that caught my attention is that several neighbors have deep water wells (around 90 meters) with submersible pumps. There are also a few houses with three-phase service and solar inverters. The electric boilers are probably irrelevant, but the water pumps operate year-round.

Could this be your source of the problems?

All of these 3 things can cause problems and it is always the best way to remove the source or add some emi suppression to these equipment.

4-5 years ago, there was not a single neighbor with deep water wells with submersible pumps. And the problem was still there.

Have you guys tried moving your setup further away from your wall outlet?

Yes, and there is no difference.

[cybepine]

One thing that caught my attention is that several neighbors have deep water wells (around 90 meters) with submersible pumps. There are also a few houses with three-phase service and solar inverters. The electric boilers are probably irrelevant, but the water pumps operate year-round.

Could this be your source of the problems?

All of these 3 things can cause problems and it is always the best way to remove the source or add some emi suppression to these equipment.

4-5 years ago, there was not a single neighbor with deep water wells with submersible pumps. And the problem was still there.

Have you guys tried moving your setup further away from your wall outlet?

Yes, and there is no difference.

And do have any high amperage draw equipment near you? Like I earlier wrote such as electric tankless water heaters?

Is is possible to cut temporarily your coax cable at the point entry and then test your problems without electricity on and off (at the breaker panel)?

Does the problems still persist?

Other than that I don't have any more ideas...

[astroasis]

One thing that caught my attention is that several neighbors have deep water wells (around 90 meters) with submersible pumps. There are also a few houses with three-phase service and solar inverters. The electric boilers are probably irrelevant, but the water pumps operate year-round.

Could this be your source of the problems?

All of these 3 things can cause problems and it is always the best way to remove the source or add some emi suppression to these equipment.

4-5 years ago, there was not a single neighbor with deep water wells with submersible pumps. And the problem was still there.

Have you guys tried moving your setup further away from your wall outlet?

Yes, and there is no difference.

And do have any high amperage draw equipment near you? Like I earlier wrote such as electric tankless water heaters?

Is is possible to cut temporarily your coax cable at the point entry and then test your problems without electricity on and off (at the breaker panel)?

Does the problems still persist?

Other than that I don't have any more ideas...

Good point about the coax cables. I'll try this week to unconnect them

[unexpected8]

I have a severed coaxial cable point next to a power outlet; could that cause any issues?

https://h.top4top.io/p_3916ly2w60.jpg

[astroasis]

I have a severed coaxial cable point next to a power outlet; could that cause any issues?

https://h.top4top.io/p_3916ly2w60.jpg

Could be. I heard they can act as antennas for emi

[MK92]

Do not waste 90$ for bullshit ferrite cores linked above, this will NOT fix your problems because the problem is low-frequency noise, not high frequency.

You would need something that would fix 10-40 khz noise, not ranges from 150+ khz to 10 mhz, but this doesn't exist at consumer level.

[astroasis]

The issue is more so on the monitor side imo, the pc psu handles things fine. For example why would multiple devices like laptops without gpus, consoles etc all have the exact same blurry display on multiple TVs and monitors? Case and point being my monitor plugged into my online ups in conversion mode provides the greatest relief above all other attempts of fixes.