[greybeard]

At first I thought the house was haunted, but I'd be very grateful for help analysing the following problem.

First, about 6 weeks ago, we went on an economy drive after the last electricity bill. Using a plug in metered socket, I discovered the workshop monitor/pc which I thought switched off when I hit the off button, was still drawing about 0.3 amps, 24/7. So I switched it off at the mains as well.
Then we noticed the electric blanket(the bedroom sockets are through the wall to the workroom sockets) didn't work properly, after 8 months with no problems. Most of the time the neon(?) dial illuminator was flickering, and the blanket might or might not get warm. Appeared to be random.
So that went back to the supplier and exchanged for a new one.
That seemed OK for about 4 days, then stopped working. The power neon was on, but no heat developed.
(It has an electronic timer/controller.)

Then we noticed the clock/radio in the bedroom was playing up, with either the dro flickering or the clock minute indicator cycling every 5 seconds.

Haunted house?

I've tracked it down so far to the fact that if the monitor is switched on at the socket and on standby, the clock/radio and the electric blanket work normally.
The same is true wherever the clock is taken to in the house.
Nothing else plugged into the socket has the same effect as the monitor.
I've tried surge protected strip sockets as well, but nothing alters the effect of the monitor.

When it's on standby, the clock and blanket work. When it's switched off, they don't.

Haunted monitor ? In use with the PC it appears to work completely normally.

Any ideas ?

It would be some help if I new what type of load the monitor is presenting when on standby, so that I might emulate the load to see if that's the root of the problem.

Thanks
John

[Al_The_Man]

I see you are in the UK so probably have a 13A Ring Main system for sockets?
I would suspect a defective connection or wiring of the PC socket, How do you turn the monitor off at the mains?
Does the socket have switched type outlet?
Reconnect or replace the PC socket for starters.
If this does not cure it, I suggest moving as you may well have a haunting.
Al.

[greybeard]

Hi Al, thanks a bunch re moving

What I have been doing today is 1. I took the clock to the furthest socket, 50 yds to the bottom of the garden - no change.
2. All the wall sockets(switched) are on the same ring, but not the cooker, and that has a separate socket, so I plugged in there - still no change.

3. I ran a cable from the monitor power plug to another socket on the lower floor, but again, no change, nor than taking the clock to an outhouse socket.

It seems that wherever the clock is plugged in, it can detect the fact that the monitor is also plugged in !
Action at a distance ??

I do have a 'scope, and yesterday fired it up and got the usual mains pick-up on the probe lead.
However, if I got hold of the end of the probe wire, I could see a lot of RF on top.
Now this may be normal, with me acting as an ariel for the nearest transmitter.
I'm a bit out of my depth here, not being a radio man, but I did wonder if a fault in the clock/radio is producing some RF which is upsetting the clock electronics, as well as the electric blanket controller incidentally, but by plugging in the monitor I'm adding a sink for the RF.
This is getting close to mumbo jumbo, but it may spark an idea in someone.
Regards
John

[Geof]

Do you have a dimmer control or anything with an electronic thermostat anywhere in the system? I came across a funny situation once where a heater was injecting a signal into the wiring and this was affecting a numerical counter display in another location.

For a while the situation was not funny; the counter was on a Gieger Counter and you can imagine the reaction when that suddenly started accumulating counts.

[Al_The_Man]

It seems that wherever the clock is plugged in, it can detect the fact that the monitor is also plugged in !
Action at a distance ??

Obviously the radio & blanket should not depend on the monitor to work.?
Both should work in a stand alone condition, try plugging into a neighbors outlet just for the heck of it.
It is beginning to sound like VooDoo rather than Mumbo Jumbo.
Al.

[greybeard]

Yes, I'd thought that that might be my next trial.
I've just been talking to the blanket service people who think that RF on the mains shouldn't affect the controller, but that just may be that they've never come across it before, so open mind still on that one.
we'll also see if we can borrow a simillar clock/radio, to see if it's only ours that does it.
I think that if it is, then it's bin time for the clock. If not, then.........?
John

[greybeard]

OK, I suppose it has now got worse.
If I take my clock/radio next door and plug it in, it can detect if my crt monitor is plugged in as well !!!!!!!!!!!!!!!!!!!!!!

We're probably on the same phase, but that does knock on the head my idea of a monitor acting as an RF sink.

Another appalling thought. I've just bought a new breadmaker as mine has gone berserk after seven years faithful service. That works on timing circuits too. At least I haven't thrown it away nor converted it into something else.

Update.
As of ten minutes ago, it now works perfectly, and I've no idea why.
Left baffled and drained. Will now make large G&T and sit in the summerhouse wondering why life is so difficult.

[Al_The_Man]

The puzzling thing to me is that you say they only work when the Monitor is ON or standby??
I can see the reverse being a problem.
Your tests seem to indicate it is mains-borne rather than RF-borne.
Many modern monitors & TV.s have switching supplies and often this is on all the time to enable the electronic start circuit.

One of the most bizarre problems I had many years ago in the UK was a customer that complained her TV soap opera was 1 week behind her neighbor.
And she was right!
But that is another story.
Al.

[greybeard]

OK. About 30 mins ago, even though the monitor was off(see update on #7), with the clock working, the bed remade and the blanket on and warming up, everything seemed to have reverted to normal.
I then went into the work room and reconnected everything in my workstation(desktop/printer/monitor/scanner), and turned the power switch on.
15 mins ago, I noticed the clock, down here with me keeping an eye on it, has now started playing silly bu##ers again. The blanket is cooling down.
Turned the blanket controllers off, and the switch on the wall socket.
Came downstairs and 10 mins later the clock is now OK.

[ckelloug]

Has the house been checked for faulty grounds? Is that earth grounds (or maybe earths) for you brits? That seems like one of the most likely reasons for something this crazy of the top of my head. I'm thinking that something that has a bad ground connection is getting a weak but usable ground through the monitor.

[greybeard]

Hi Cameron, and welcome to the seriously crazy house.
Like most clock/radios here, it's double insulated with only twin connection and no earth.
Likewise the electric blankets - no earth leads.
John

[daedalus]

assuming its noise the monitor clearly isnt the root cause of the problem, so have you tried disconnecting everything else plugged in apart from the clock(like heating, appliances etc) to see if one of them is responsible?

[ckelloug]

In the U.S. where we have a single phase distribution, the neutral is grounded. If the ground at the panel is bad or there is something flaky in the neutral circuit where it is either connected to ground where it shouldn't be or floating, bad things happen.

The situation you describe sounds somewhat like a floating neutral although some allowances in this discussion may have to be made for the fact that UK power is wired somewhat differently although I don't remember the difference. I know the voltage and the frequency are different but I believe there could be other differences.

Regards,
Cameron

[greybeard]

assuming its noise the monitor clearly isnt the root cause of the problem, .......

I don't quite follow the logic there.
If I remove the monitor, there is a problem.
If I replace it, the problem disappears.
If I remove the clock, the blankets work.
(The last statement has to be modified by the word "eventually". Like many glitches in computers, it seems that time is needed for voltages to decay, and this is frustratingly unpredictable.)
While it may be true that the monitor isn't the "root cause" in the sense that it is generating the conditions, it is only the presence/absence of it that is interacting with the clock/radio.
For the moment I'm sticking with the idea of a fault in the clock/radio being moderated by the monitor, but the fact that it seems to occur over a distance greater than 200yards of power line is stretching the idea somewhat, I freely acknowledge.

[greybeard]

In the U.S. where we have a single phase distribution, the neutral is grounded. If the ground at the panel is bad or there is something flaky in the neutral circuit where it is either connected to ground where it shouldn't be or floating, bad things happen.

The situation you describe sounds somewhat like a floating neutral although some allowances in this discussion may have to be made for the fact that UK power is wired somewhat differently although I don't remember the difference. I know the voltage and the frequency are different but I believe there could be other differences.

Regards,
Cameron

Let us suppose the ground to the socket in the bedroom was the problem, then that woudn't account for the fact that the clock plays up in other sockets elsewhere.
If it was the ground to the monitor, other devices would provide a suitable path to ground, but they don't.
It's only the combination of clock, plugged in anywhere, with either monitor plugged/not plugged in anywhere, that produses the changing symptoms in the clock. And once the symptom has appeared in the clock, then the blanket wont work correctly for some random time delay, even when the clock condition is righted by plugging the monitor in once more.

John

[greybeard]

Geoff - sorry I'm missed your post earlier.
No, as far as I can think, the only timer switches we have are mechanical, and there aren't any dimmers in the house at all.
I've logged all the timer controls, and none of them operate at the crucial times, which are really only produced by me frantically plugging or unplugging equipment.
And talking of Geiger counters, no it isn't me . I've been assured that my radiation shouldn't affect anything/anyone else(even though it does trigger a Geiger)

[martinw]

Dear greybeard,

Forensic stuff is a right pain!

IMVVVVHO, I think that Al the Man may have a point as regards dodgy connections, (and maybe intermittent Earths as other people suggest).

It may well not work, but how about this test...

1) change the socket at the original PC position, and check LNE (Live , Neutral , and Earth)
2) check the plug wiring ditto
3) check ring main continuity for LNE
4) check your Earth bonding.

My best guess is that SOMEWHERE you have a dodgy electrical connection that is stuffing intermittent PSU glitches into logic circuits of all your "consumer electronics", some of which may be more robust than others. That may be...

1) from your house wiring

2) from a fault in one of your many household gadgets ( that includes all the ones you have, but have not mentioned)

3) from a fault in a plug between the above two

I know absolutely nothing about RFI, BTW.

Best wishes,

Martin

[ckelloug]

John,

I think martinw has hit the nail on the head. If you have a voltmeter and know how not to kill yourself with it, check the live to neutral voltage, the live to ground voltage and the neutral to ground voltage. I suspect that at least one of these will be obviously incorrect.

If you have a floating neutral, the voltage from the live to the neutral will be lower than it is supposed to be because the neutral will be higher than it is supposed to be. That could explain the symptoms you are describing. Even on plugs like the clock that are only two prong, if the neutral is floating, problems will occur. In this case, the problem would most likely not specifically be on the ground wire itself but with the neutral and its connection to ground.

Best of luck.

--Cameron

[Geof]

.....For the moment I'm sticking with the idea of a fault in the clock/radio being moderated by the monitor, but the fact that it seems to occur over a distance greater than 200yards of power line is stretching the idea somewhat, I freely acknowledge.

I don't think you are stretching, provided there are no transformers intervening; RF signals superimposed on AC lines do not decay much with distance.

[martinw]

Dear Cameron,

We meet again! Hope all well with you.

Actually, my best guess is that intermittent dodgy connections may well not be spotted with a meter. These types of fault are a right PITA.

Best wishes,
Martin