Monitors turning off when one of them is unplugged

OK so this actually work related but it has me stumped.
The IT unit at a school has new wiring (1 year old) and on one work station bench there are about 12 or so computers and monitors all powered the same ring circuit.
Each double socket powers one computer and its associated monitor.
It has been discovered that when you unplug or plug in a monitor that sometimes some of the other monitors (either to the left or right of the monitor that is been plugged and unplugged) lose their display for a few seconds[1].
I have checked the circuit and it is fine.
Any ideas.
One other bit of info. The slower you plug or unplug the monitor seems to make this happen more often.
I can go back in for another look if anyone wants any more info. My job was only to confirm that the circuit was safe but I like a mystery.
[1] So the school closed the IT room for H&S reasons.
--
Adam

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARW wrote:

Presume by "unplug" you mean the power lead, rather than the VGA/HDMI/etc lead?
Do the monitors have external power bricks, or just an IEC mains lead direct to the screen?
If they have bricks, do they do it when when brick is unplugged from the monitor, or just when the brick is unplugged from the mains? Do they do it when the monitor it powered on/off by the front panel button?
Are they no-name or branded monitors?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 19/09/2017 19:48, Andy Burns wrote:

Yes the 13A socket.
I'll try and have another look later in the week.
ISTR the monitors had bricks, and were either Dell or HP.
No one tried the on off button on the monitor.
--
Adam

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
To answer an earlier response. We stopped using master switches for banks of computers in classrooms when the computers started blowing their PSUs. If you turned of 30, only 25 would come back on. After a short while the d ealers wouldn't fix em under warranty.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 19/09/2017 19:30, ARW wrote:

Sounds like some sort of interference from sparks disrupting the signal integrity. I presume they are all on digital interfaces these days?
Does it also fail if you plug and unplug an anglepoise lamp or similar 60W load that isn't one the monitors.
I presume you have eliminated the possibility of loose wiring in the various sockets on the ring main (and/or it not being a proper ring). A better quality of interconnect between PC and monitor might fix it.
Be worth checking that there is a proper earthing arrangement too.
Why are things getting plugged and unplugged though? Less wear and tear to switch off at the wall or have a master off switch for them all.

My favourite in the days of tube based monitors when mobile phones were new and exciting was watching the screen go crazy as the phone woke up when it was about to ring and accept a call. It gave about 3s warning.
--
Regards,
Martin Brown
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 19/09/2017 21:01, Martin Brown wrote:

I'd say the same. We once had a set of desks here where one monitor continually flickered after we replaced the PCs. We eventually found an IEC lead on an adjacent monitor (plugged into the same PDU) had a rewireable plug (rather than a moulded one) with loose screw connections. I'd imagine if it was a higher wattage appliance it would have got hot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, 19 September 2017 19:30:14 UTC+1, ARW wrote:

I have similar problems with laptops and TVs. Turning the TV on/off or plugging/unplugging it wakes the laptop up.
Owain
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gowanhill.com wrote:

Does the laptop "know" about the TV via a WiFi or Bluetooth connection?
Could it be something simpler such as the physical act of plugging nudges the mouse which wakes up the laptop?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That’s a different problem and easy to fix by turning the wake on features on the laptop off. Usually there is a wake on for the mouse, keyboard lan etc in the laptop settings.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 19 Sep 2017 19:30:12 +0100, ARW wrote:

I am imagining that somewhere buried below you might find one of those "smart" extensions which powers down when the current draw from a specific socket goes to zero. They had a brief vogue when people were mixing all sorts of kit, and just switching the PC off would also power down printer, monitor, scanner, speakers etc etc.
The fact it's a school is suggestive. Just the sort of institution to mandate such kit as part of a "green" initiative.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jethro_uk wrote:

Schools in general seem quite "anti" 4-way extensions ... if it's an ICT suite they do tend to install sufficient power and data points.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 20 Sep 2017 11:59:26 +0100, Andy Burns wrote:

Maybe in sight, but what horrors are locked away below ???
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 20 Sep 2017 11:59:26 +0100, Andy Burns wrote:

Meanwhile, chez Jethro, 4-way extensions have become a standard feature.
I cannot believe the hours I have spent scrabbling around behind furniture to access a plug in a room - notwithstanding the usual plug/ appliance ratio problem.
Not sure where inspiration came from, but about 10 years ago bought a bulk of 1m 4-way extension leads. Plug into a socket in a room and - presto ! You've got access to moveable power. Since the biggest thing that is ever plugged in is the hoover, I feel we're quite safe.
Cheaper than fitting 4 more double sockets (all of which would be full now anyway). Just have a rule that we never plug another adapter into an adapter.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

+1 (or perhaps I should say +4?)
We have dozens of them, for the same reasons you state.
--
Today is Prickle-Prickle, the 45th day of Bureaucracy in the YOLD 3183
I don't have an attitude problem.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 21 Sep 2017 10:04:48 +0000, Huge wrote:

It's one of those "how on earth did I not think of it before" ideas.
Although pricing may be an issue. IIRC last time I bought "an" 4-way lead it was a pack of 3 for £10 - cheaper than the 3-way cube adapters (which I have junked).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

did you know you can now get 6 way, 8 way 10 way and even 12 way ones?
--
from KT24 in Surrey, England

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have 3 off 12-way and 2 off 20-way ones in my study.
--
Today is Prickle-Prickle, the 45th day of Bureaucracy in the YOLD 3183
I don't have an attitude problem.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 21 Sep 2017 10:25:44 GMT

You must have a load of wall warts. I've not found a need for more than a few 6-way strips, I like the individually switched ones. Using 4-way USB chargers saves a few sockets.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I do too.

Load of all sorts of things in one place.

Then you must have fuck all stuff.

I leave almost everything plugged in all the time and only have a few of the 6 way individually switched ones in a few places like where I brew so I can turn lights plugged into it and brew heaters etc on and off individually.
But all the lights will be Philips Hue soon, so I wont need that for them either. Same with stuff like brew heaters, that will be wifi controlled now too.

I normally use the ones that come with the device with the bigger stuff like tablets and phones and charge the other stuff like the bluetooth headsets from the PC with multi USB hubs.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 20/09/2017 10:43, Jethro_uk wrote:

No adaptors, just MK double sockets with one socket for the computer and the other for it's associated monitor.
--
Adam

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.