Slight static discharge causes second monitor to go blank

[mafocari]

I've had a three monitors connected to the back right USB-C port on my MacBook 2019, all through a 3-port adapter I bought at Walmart, and even the slightest little static shock from my pants or whatever to the table can cause the monitor to blank out, and sometimes stay off, so that the monitor appears to not be aware that there's output going to it from the Mac, but the Mac doesn't seem to be aware that the monitor is not aware of the Mac. It's a bizarre situation.

I can try a USB-C to DVI cable, but I had a USB-C to DisplayPort cable on the adapter before.

I could try replacing the adapter with a USB-C to DVI cable, but I don't know if that will fix it. I don't know how much money I'll have to spend to fix it. The problem could be the Mac, the adapter, the table... I don't know. My first monitor is coming from the front left USB-C port to HDMI, and the previous monitor was USB-C to DisplayPort.

Have you experienced problems like this with the Mac or a port? Maybe the adapter is not well shielded, but maybe the Mac has an issue. I'm not sure how to figure out if the Mac or that port has an issue.

 

[chscag]

It certainly sounds like a case of poor shielding and/or improper grounding. The 3 port adapter you purchased at Walmart may be the culprit.

This time of year when the weather gets colder and consequently drier, static buildup becomes more serious. I noticed when sliding out of my auto front seat and touching the door handle, I can feel a slight shock and pop.

Your 2019 MacBook is likely properly shielded and grounded. I would focus on the adapter and cables to resolve the problem. This is assuming your monitors are also properly shielded and grounded.

 

[Kenney]

Cscgag is correct, it’s a grounding problem. Is the outlets that your power strips are plugged into three prong? If not that could be your problem. Also a humidifier in the area would help also.

 

[mafocari]

It is colder and drier here now, and I do notice more static electricity buildup and discharge everywhere.

The funny thing is that the discharge only happens from my pants touching the bottom of the table (the metal or plastic (?) part), no matter what pants I'm wearing (sweatpants or jeans... maybe I shouldn't wear pants?). The table I'm using is a Mainstays 6-foot fold-up table (maybe I should use a wooden one?!).

The monitors are set up as normal as I've ever seen, and I've never had this problem before. They all use 3-prong plugs.

The power supply is a Tcstei PS953 Surge Protector with 12 Outlets and 4 USB Ports I bought on Amazon, and I think the problem also happened with the previous surge protectors, a Dynex like the current one and some generic 6-plug strip.

The MacBook is plugged in with the power supply Apple put in their box, which only has 2 prongs; I'm assuming this is intentional on Apple's part... I don't know why they don't use a ground prong, but I haven't had static electricity issues with Macs.






Note that the adapter used to be laying directly on the table, and putting the box under it didn't fix anything.

The surge protectors have shifted positions over the months like any other, and plugs from devices have had different arrangements with no noticeable difference in this issue.

I think maybe the issue is the adapter or the table, though it'd be nice if I could jerry-rig a grounding workaround somewhere... any ideas? I'm wondering if wrapping some thin metal wire around the DVI adapter metal that plugs into the adapter and then stringing that wire somewhere it can ground would prevent it from grounding into the monitor haha.

I bought a USB-C to DVI direct adapter, which may fix the problem, who knows. I hate wasting an adapter lol

 

[Kenney]

There is little that you can do without knowing something about Electricity. If the electrical outlet in or on the wall is NOT grounded then you are SOL. From your pictures it looks like your in the basement. Is the wiring from the outlet in conduit all the way back to the Fuse Panel ? It will take someone that knows what they are doing to safely check the ground to the Fuse Panel (ELECTRICAL SHOCK CAN KILL) and repair or replace the wiring if not. Get an Electrician to do this.
Adding a Humidifier to the room (40% Humidity) would help.
Static discharge can and does destroy electronic components. The more frequently they occur the faster this happens. This gets expensive.
If the electrical box on the wall IS grounded then adding a ground strap to the desk and maybe an antistatic mat to the floor also.

KenK

 

[mafocari]

If the electrical outlet in or on the wall is NOT grounded then you are SOL.

I'm assuming the wall outlet is as grounded as any other otherwise I'd be having a lot of problems with other things plugged into it, not just monitors plugged into the adapter, when there was static discharge to the table (even the tiniest amount). Maybe you could explain how that would work so uniquely?

I'm not in a basement, and I'm not able to check the wall wiring. I don't know where it goes. I have a fusebox in another room but I feel like this is going down a broad path for such a unique issue... is there no way to test whether it's the adapter or the outlet besides getting into the fusebox and wall wiring? I'm not having any disruptions with anything but the monitors through the adapter. I'm waiting for a direct USB-C to DVI cable to arrive, but since you seem skilled at electrical troubleshooting, I think maybe you can come up with a safer suggestion than getting into my wall wiring and fuse box. What do you think? Is there something safer I can test and how would you do it?

I suppose I can try a humidifier if the cable replacement doesn't work... but I'm not having an issue with all of the other electronics in any rooms.

adding a ground strap to the desk and maybe an antistatic mat to the floor also

I suppose this is a good idea... I'll have to figure out how to do the ground strap. Not sure how a floor antistatic mat will fix this, but I'm going to get an office chair carpet cover... maybe that will help?

This is a such a strange issue.

 

[Kenney]

Please understand that due to "a possible electrical shock hazard" I can't suggest that you try to troubleshoot your electrical wiring. You will need an Electrican for that. For a better understanding I would suggest a web search on "How to Eliminate Static Electricity", and on " Understanding electrical Grounding and How it Works".

Most of the "Home Offices" that a homeowner builds do their own wiring and may not know what they are doing when it comes to "sizing the circuit" and making correct connections. Like leaving out or not connecting the ground wire in outlets or only connecting 2 wires to an existing circuit. While these might work it can cause all types of problems.
Not saying you did this but maybe a previous owner did.

Also:
Leave it to an ET to forget KISS (Keep it Simple Stupid)
I may have misunderstood you original problem, Did this just start? (winter months) if so then it is probably a humidity issue and can be fixed with anti static sprays and or a humidifier. This is a lot cheaper way to start. Also forgot about these, Lowes, Home Depo, or Ace, etc. should have them "grounding tester electrical". This will tell you if the outlet is properly grounded. (If not call an Electrican)

KenK

​

 

[mafocari]

Most of the "Home Offices" that a homeowner builds do their own wiring and may not know what they are doing

The room is simply a second bedroom, not a home office; I'm just using it for work. That's completely irrelevant anyway, any room could be miswired whether it was intended as a home office or not.

I swapped out the adapter for a USB-C to DVI cable, and while touching the table with some discharge causes the monitor to blink once or a few times, it doesn't shut off or screw up the display anymore. So the adapter seemed to have caught the discharge and send most of it straight to the monitor in some way that jerked around with it. The new cable seems to be better with it, or at least not send chaos to the monitor. My bet is the adapter will work just fine in any other situation, though I don't know when I'll ever use it again. I hate wasting money on an adapter like that.

I'd think about bigger solutions if I can't just blame it on the cable/adapter to the monitor, but the fact remains that the MacBook or its port could still be to blame. I don't know how to troubleshoot that, but I got the same behavior from the front port as from the back port. I could try swapping the cable from right to left, but that's inconvenient and awkward, and really, it'd be nice to know if anyone else has had weird electrical issues like this with MacBook or its ports. The whole MacBook surface is metal (lid is closed), so who knows why only the monitors connected to these ports or their cables are having static discharge issues... if there's some way to troubleshoot the MacBook or its ports in relation to electrical output, I'd love to test that, but I'm not sure how.

Have you ever had issues like this, or tried testing the ports? That's what I'm curious about now. I'm not an Apple fanboy enough to think that the problem couldn't be with the MacBook 2019's design.

 

[mafocari]

You know, I realized something else was going on with another computer in the room that I thought was just me walking too hard or sitting down too hard or bumping something too hard to wake up the computer (through inadvertent mouse wiggle)... today I sit down, hear a loud electrical shock from my pants to the table, and not only does the second monitor blank out for a sec, but the other computer (plugged into a different wall socket) turns on before I even sit down...

So!

electrical

It seems like there may be a grounding issue in at least the wall outlet my work table is plugged into... that may also be affecting my other computer! That other computer I noticed recently (I actually haven't used it in months) had a blue screen "store" (storage?) crash... which could have happened from an electrical issue!

So, now, I guess I need to file a work order to have the outlet(s) investigated for proper grounding...

It's just so strange that it's only affecting the 2nd monitor and that computer behind me... I'm good with computers but I don't know that I'll never understand electrical

 

[Kenney]

In most cases there are UP TO 8 outlets on a circuit (15 AMP breaker). These outlets may not be in the same room. One "bad" outlet can cause problems for all of the others.
I understand that this may take some $ to Fix ( service call ) but it is a lot cheaper than having to replace computer equipment, and still having to fix the problem, and also possible more serious issues.
Please get it looked at.

 

[mafocari]

In most cases there are UP TO 8 outlets on a circuit (15 AMP breaker).

I'm not sure where the circuit is, but the room has 5 outlets with two 3-prong jacks (?) each. As far as I've ever seen, before this current issue, they've all behaved as normal. I'm not having issues with the other 3 outlets (just the two on my work side of the room, apparently).

The current surge protector has 12 3-prong ports and 4 USB ports; I mentioned the brand previously, but here's the literal listing: Amazon.com

That device is plugged into the corner outlet, in the bottom socket (due to the shape of its wall wart), and the top socket has the lamp plugged in; the lamp is powered on by the room's light switch, so that that socket is enabled/disabled by the room's light switch across the room. For most of my existence here, I've only used that socket for the lamp; it's only been the last year that I've used it for my work computer, and the 2nd monitor issues didn't start immediately but started growing worse and more erratic over the months regardless of devices used.

The previous device was a Dynex - 8-Outlet 2-USB-Port Surge Protector Model DX-AVSP8, which I probably bought at Best Buy: Dynex - 8-Outlet 2-USB-Port Surge Protector - Multi (bad link removed)

That one has been used the majority of the time for that wall outlet (same socket), and the issues have not changed due to swapping out.

So, if you see anything obviously bad about those, let me know, and recommend something. I have other surge protectors, but I just can't say that the surge protector is the problem.

I understand that this may take some $ to Fix ( service call ) but it is a lot cheaper than having to replace computer equipment, and still having to fix the problem, and also possible more serious issues.
Please get it looked at.

I wasn't arguing against making a service call or having it fixed Me saying "I guess I need to file a work order to have the outlet(s) investigated for proper grounding" means I'm for having it fixed. The issue with that of course is that the problem may not be the wall outlets... but I'm not against having them investigated, so I don't need to be further convinced to try that. The problem still could be the MacBook 2019 design, and if so, it'd be nice to know mitigations/fixes for it.

 

[chscag]

Several suggestions before calling in an Electrician:

Buy one of these to test your outlets:

https://www.amazon.com/dp/B0012DHVQ0/?tag=macforums0e4-20

Surge protectors are okay and I also use several around my home, however, for my computer equipment I use an UPS. You can buy a good UPS from Amazon or any other store that sells them.

https://www.amazon.com/Computer-Uninterruptible-Power-Supply-Units/b?ie=UTF8&node=764572&tag=macforums0e4-20

 

[mafocari]

Buy one of these to test your outlets

Ah OK! Thanks.

Maybe I should use a UPS... but I don't know why none of them seem to come with more than 1 USB port.

 

[mafocari]

I wonder if replacing the desk would fix it... it's a nice long foldable desk that I can swap out for a guest bed when I need it, but it may be contributing too much to the static discharge to the monitors. Maybe a proper desk from Office Depot or something would better distribute the discharge.