black screen when fridge motor or heater starts

[Avo Mk8]

Hi lolb72
A quick thought after seeing your photo's.
It would be worth swapping the HDMI cable you are using for the Blu-ray player, for the PC one.
Or as a quick test, just take that lead out of the Blu-ray and put in in the PC, to see it it changes the situation at all.
I suspect the ferrites might be a red herring - in my limited experience they seem more to do with getting equipment to pass EMC tests (emissions?), and I fear their effect may be too subtle to help here.

I'd pin my hopes on a socket strip with an EMI filter.
Or go the whole way and invest in a UPS, which would also tackle any voltage dip issue as described by marconi.

 

[westward10]

I don't know the reason for this but about five years ago I was working in someone's flat and they said switching the fluorescent light on in the kitchen pinged off the TV and Sky box, I tried it and sure enough it did. They had table lamps in the kitchen and had stopped switching on the main light.

 

[pc1966]

I don't know the reason for this but about five years ago I was working in someone's flat and they said switching the fluorescent light on in the kitchen pinged off the TV and Sky box, I tried it and sure enough it did. They had table lamps in the kitchen and had stopped switching on the main light.

About 1996 I got an ESD test gun and, obviously, the first thing I did was wind it up to its maximum of 18kV and try discharging it on the chassis of my office PC. It was fine but minutes later the guy in the next office came in angered by his crashing and needing to power off and back on again to get his mouse working.

I was told in no uncertain terms not to use it again in that area!

 

[pc1966]

As @Avo Mk8 suggests, try an HDMI cable swap first to see if it makes any difference. If so then maybe buy a better one and possible a few of the ferrites to help it (and any older HDMI cables).

Next cheapest would be to get a power block with a EMI filter / surge protection in it and see if that fixes it.

A UPS is a pretty expensive option, though at least you could watch TV for a few tens of minutes more if there is a power cut...

 

[marconi]

I am not sure that the extension-lead-to-another-circuit test will conclusively distinguish between voltage brownout and interference. Moving the supply for the monitor and TV to a point where it shares less common impedance with the fridge / heater is likely to reduce the amplitude of any transients reaching the mains leads and PSUs that might be coupling into the signal circuit. So we might find that it 'solves' the problem without indicating what the problem was and therefore how to solve it permanently.

It is also hard to see how a heater plugged into an intact circuit could cause a brownout sufficient to affect anything. The element resistance is lower when cold but not much lower, so a 5% circuit VD might become 10% momentarily, not enough to disrupt a normally-functioning SMPSU.

My starting hypothesis for analysis of this problem is there may be a defect in the wiring along the lines of what littlespark shows in #5790 of the thread 'Dodgy trade pictures for your amusement' - a connection or connections within or without the flat which is/are not made satisfactorily the effect of which becomes/become manifest during high current events.

The OP says a fridge starting or a heater starting causes the problem - these appliances have different inrush current characteristics but one thing in common - a large current - the former briefly and the latter longer term and roughly of the same magnitude - and yet they cause the same effect - the brief blanking of the TV screen when used a monitor for the CPU

So for me there is something about the reaction to and recovery from these switch on events (note not switch off) which I reckon is taking place within the CPU/PC - it only happens when I am working on my PC - which is causing the problem - the stress of a poor connection like littlespark illustrated during switch on of the fridge or heater.

Postscript: Electrical contact theory, A-spot, electrical contact resistance, electron ballistic conduction, Sharvin resistance, Ragner Holm on contact conduction see:

Electrical contacts - Wikipedia - https://en.wikipedia.org/wiki/Electrical_contacts

 

[Avo Mk8]

A UPS is a pretty expensive option, though at least you could watch TV for a few tens of minutes more if there is a power cut...

Taking the cheapskate route, the APC es700 UPS can be had on eBay for around £25. The one below went for £10 with an adequate battery. And a new Lucas battery for it can be bought for £15, so definately under £50. It has half of its 8 socket outlets providing filtered direct mains, and the other half uninterrupted power. So you get the filtered extension lead thrown in!

UPAPC Back-ups ES700 | eBay

Find many great new & used options and get the best deals for UPAPC Back-ups ES700 at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

But I accept the delivery costs just as much

 

[scootknew]

loose cable at monitor or at pc tower

 

[Avo Mk8]

So for me there is something about the reaction to and recovery from these switch on events (note not switch off) which I reckon is taking place within the CPU/PC - it only happens when I am working on my PC - which is causing the problem - the stress of a poor connection like littlespark illustrated during switch on of the fridge or heater.

Agreed that the 'blank screen' on the TV only appears to occur when its displaying the PC output.
But one cannot yet conclude the PC is the fundamental cause of this.

It would be useful to connect a monitor through a VGA connection (if available) to the pc, to see if that still blanks out.
Or failing that, continue typing into a document on the PC during the 'blank screen' event, and see if that input is included in the document when the TV resumes its display.
I'm yet to be convinced it's not the TV itself responding to a transient in its HDMI input. But happy to be proved wrong when the issue is finally resolved!

 

[marconi]

Dear AVO Mk8: But one cannot yet conclude the PC is the fundamental cause of this. And nor have I yet. I have constructed an alternative hypothesis - a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

We have probably scared Jolb72 away with our technobabble.

 

[Lucien Nunes]

True! OP - please ignore the geeky internal discussion, we'll guide you through this! Let us know if you have a chance to try the other, better HDMI cable in the computer, or powering the computer and TV via an extension lead from a socket on another circuit.

@marconi I agree that evidence is limited and your hypothesis is valid, but I am still inclined to point to the signal source, sink or interconnect simply through extensive experience of exactly this symptom. I have been called upon to troubleshoot literally hundreds of "display signal sometimes blanks" faults in many kinds of systems with many interconnect flavours - DVI, HDMI, LVDS, HDBaseT, Crestron DM over copper or fibre, etc. - obviously not all provoked by mains devices switching on. But a dozen or more were clearly tied to a switching event. In every case excessive interference, faulty signal source or sink, or faulty or non-specs-compliant interconnect was the cause while power supply played no part.