Mini Fridge causing TV to black out !

[jt123]

Hi all,

My apologies in advance if this is posted in the wrong category, there were a few options it could've potentially fallen under.

We have just completed our garage to home cinema conversion, but having a small (major!) issue. In the Cinema we have all the usual tech you'd expect, a projector, Denon Receiver (amplifier), YouView Box, Firestick, etc etc.
We also have a mini-fridge. All this runs on a 20A Radial.

When the compressor on the fridge fires up, it sets the screen blank. Through process of elimination I've narrowed this down to being the receiver at fault, rather than the projector. When the compressor turns off, there's no interference.

I have been advised this could be one of two things, RF interference, or the current being drawn from the fridge is causing a voltage drop. This I think is unlikely because we're not talking about a big american sized fridge freezer, it's a mini-fridge pulling 65 watts at max load!

In a bid to fix either of these issues, I have ordered a UPS to run the tech from . But my question is, is it Normal for the fridge to be causing interference? i.e. Do I need to think about getting the fridge replaced? In hindsight it wouldn't have been difficult to run a separate circuit for the fridge when doing first fix, but it's a bit late for that now. We have always had our Kitchen sockets on the same ring as the lounge and never had an issue with the kitchen fridge interfering with the lounge TV, so the wiring setup in the cinema isn't anything out of the ordinary I don't think?

Would appreciate any advice and apologies for rambling on

 

[jt123]

I should add that when the screen goes blank, if I change the input channel on the receiver, and put it back to the one it was on, it's fine again even whilst the fridge is running.

 

[Pete999]

Only when the fridge compressor starts up, all on the same circuit? I recon you have a volt drop problem, with all that sensitive kit on one circuit with the fridge, fridge starts up, compressor dragging the voltage down, electronics not liking the V, pretty sure that's the reason unless one of the Scientists on the Forum can conjure up a good reason.

 

[static zap]

If you suspect ..

...one of two things, RF interference,.....

Hunt out am AM / MW radio ..
(During day between stations ) When fridge starts ...
If its a long buzz , may be loose fuse/screws in fridge plug ..(worn out thermostat) etc

 

[Shoei]

Best guess is the receiver is oversensitive to spikes on the mains, although fridge compressors are low power, they're inductive and switching can produce some hefty transients, especially if a sluggish thermostat isn't switching cleanly. If it's that your UPS will probably filter it out although it's an expensive way to get a filter.

To investigate I'd try running the fridge on an extension from another ring if one is near enough, if that stops the problem then it's likely to be conducted spikes on the mains and a filter should clean it up. If it doesn't help then it could be radiated noise in which case the radio check suggested by @static zap would be a good thing to try.

 

[jt123]

Only when the fridge compressor starts up, all on the same circuit? I recon you have a volt drop problem, with all that sensitive kit on one circuit with the fridge, fridge starts up, compressor dragging the voltage down, electronics not liking the V, pretty sure that's the reason unless one of the Scientists on the Forum can conjure up a good reason.

I've just tr

Best guess is the receiver is oversensitive to spikes on the mains, although fridge compressors are low power, they're inductive and switching can produce some hefty transients, especially if a sluggish thermostat isn't switching cleanly. If it's that your UPS will probably filter it out although it's an expensive way to get a filter.

To investigate I'd try running the fridge on an extension from another ring if one is near enough, if that stops the problem then it's likely to be conducted spikes on the mains and a filter should clean it up. If it doesn't help then it could be radiated noise in which case the radio check suggested by @static zap would be a good thing to try.

Thank you, so... I've tried what you suggested. Ran an extension cord from the hallway which is a different circuit, fridge is cutting in and out with no interference to anything.
I have "sort of" fixed it after lots of extension leads and unplugging/plugging in cables.... and it's not the receiver that is being affected like I initially thought.
The thing that was confusing me is that this has only just come about these last few weeks, so I was thinking what have I done in there the last few weeks. Then I remembered, I installed this cheap little IR Extender a few weeks back,

https://www.amazon.co.uk/gp/product/B01A6WBMC6/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

when I removed this then I don't get any interference from the fridge even when it's plugged in on the same circuit. I've concluded that the the little adaptor that sits inline between the receiver and projector is not shielded (or very cheaply made) so is allowing the interference to interfere with the HDMI signal - does this seem a realistic explanation? I have a reasonable understanding of all this but this is going over my head a little.

So my concern is, is the fridge causing this interference an issue- do I need to fix the actual cause of the issue, or is it quite "normal" for a fridge to do this? Also, I have ordered some of these: 20Magnetic Clip-on Ferrite Ring Core RFI EMI Noise Suppressor 3.5/5/7/9/13MM 786862921287 | eBay - https://www.ebay.co.uk/itm/20Magnetic-Clip-on-Ferrite-Ring-Core-RFI-EMI-Noise-Suppressor-3-5-5-7-9-13MM/123374559640?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648

To put one on the cable of the fridge- Good idea?

Again, sorry for the long post but the help is much, much appreciated !

 

[Shoei]

I think you're on the right track suspecting that IR extender, don't know how it transmits the remote signal down the HDMI alongside the regular digital data but it's plausible that noise from the fridge is being picked up from the receiver and corrupting the HDMI link.

If the extender allows the HDMI signal though with the IR receiver unplugged you could try that, if the problem goes away it would support the idea that the receiver is picking up from noise the fridge.

The ferrites you've ordered are well worth a try but it can take some experimenting to get a result. Clamped to a cable they help block common-mode transients but may pass noise from differential currents. An inline mains filter mounted close to the fridge may help in that case. Always worth checking with the AM radio as @static zap suggested, if it's a noisy thermostat then replacing that could help.

 

[jt123]

I think you're on the right track suspecting that IR extender, don't know how it transmits the remote signal down the HDMI alongside the regular digital data but it's plausible that noise from the fridge is being picked up from the receiver and corrupting the HDMI link.

If the extender allows the HDMI signal though with the IR receiver unplugged you could try that, if the problem goes away it would support the idea that the receiver is picking up from noise the fridge.

The ferrites you've ordered are well worth a try but it can take some experimenting to get a result. Clamped to a cable they help block common-mode transients but may pass noise from differential currents. An inline mains filter mounted close to the fridge may help in that case. Always worth checking with the AM radio as @static zap suggested, if it's a noisy thermostat then replacing that could help.

Yes with the IR receiver unplugged the interference goes away

Yes I will definitely give the radio test a go over the weekend.

What is the inline mains filter, where could I get one of those?

 

[GeorgeCooke]

So my concern is, is the fridge causing this interference an issue- do I need to fix the actual cause of the issue, or is it quite "normal" for a fridge to do this?

Yes you do need to fix it. Creating interference is illegal.

Posible a capacitor across the fridge contacts along with an inline filter will fix it.

 

[jt123]

Yes you do need to fix it. Creating interference is illegal.

Posible a capacitor across the fridge contacts along with an inline filter will fix it.

Thank you,
Where can I get a Capacitor & inline filter, I've searched online but I'm not too sure what I'm looking for.