lightning storm

You should have immediately unplugged your audio system from the wall outlet.

It's possible slight damage may have occurred to some circuit board traces. It's called electronic rust. 

I would suggest you unplugged your audio system from the wall outlet during lightning storms. 

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Yes, it is probably EMI either entering directly into your system or EMI affecting your power lines.  In any even, it is better to turn everything off during a storm.  Even better is to unplug the gear because a direct hit of lightning could be powerful enough to jump the switch in your gear.

Even when lightning does not directly strike a power line the magnetic pulse is picked up by every cable nearby, from high tension lines to your house wiring, antenna cables and Internet provider's wiring.  

We don’t always know when a surge will come down the line so having a good surge protector is essential IMHO, but even then I would absolutely recommend unplugging when you know a big storm is coming through.  Sometimes I even turn off my HVAC and range as well, despite having a whole house surge protector.  

Thank you for your responses. Much appreciated and I will be turning everything off and disconnecting in the future.

How is "electronic rust" detected and repaired?

Storms can cause slight shifts in ground potential, which may temporarily aggravate grounding issues, causing hum or static. If you only heard static during a storm but it went away afterward, it was likely due to temporary EMI or line noise.

BTW, Electronic Rust has nothing to do with lighting or thunderstorms. It is an informal term often used to describe corrosion or degradation of electronic components or circuit board traces, typically caused by moisture, oxidation, or chemical contaminants. It’s not actual rust (iron oxide), but it behaves similarly by slowly damaging the delicate metal pathways that allow electricity to flow.

First question  unplugging it is a good idea ,but 2 nd what are you using 

for a line conditioner, Surge protector ? You Donot want anything that uses MOVs

they totally destroy your current capabilities  and should be avoided ,

and you should have Copper - plated recepticle ,for cheap brass oxydizes

try cleaning out a recepticle. 

Once again, I urge all Agoner's to invest in a whole house surge protector, when possible.

@jea48 , nice to see you here. I have always appreciated your knowledge of all things electrical.

bob

As a retire audio tech, I saw my share of lighting damage over the years. Unplugging is the ONLY way to totally protect your equipment, and that includes internet cable and any type antenna cables. Those also create a path to ground, and if connected, can be a source for damage. 

HAHA 😆 😅. Be careful with that back around 1998 when the strip protectors weren't so good a lightening storm fryed the transformer in my Kenwood receiver and no parts available so it was done. I did find a replacement on eBay for $475 I think it was. Get one of those big ones that the whole thing plugs into the wall , no cord at home Depot they have a $10,000 protection guarantee.

EMI damage? Recently my F150 sat next to a pine tree that took a hit. $5k damages to the electrical. Luckily no damage to my HT/music system however my modem & charger to my laptop did not fare so well. $1k deductible on the Ford so not as bad as it could have been. 

EMI damage? Recently my F150 sat next to a pine tree that took a hit. $5k damages to the electrical. Luckily no damage to my HT/music system however my modem & charger to my laptop did not fare so well.

I don’t think the damage was caused by EMI. More likely from an electromagnetic pulse (EMP).

Edit:

I ran across this device on the Net. Does it really work?

EMP & Lightning Protection for Vehicles (DC-12V-W)

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The Internet is filled with stories about lightning coming in via the cable modem and taking out entire HT systems via burned out Ethernet ports. 

Most Internet users rely 100% on Wifi, but for those of us who use it professionally or just don’t like to have Wifi problems we wire all our big gear up.  Our work computer, TV, music streamer, etc. and so I take a paranoid approach.   Using Ethernet is great for reliability but also leaves us more exposed to incoming surges.  

I use an external coaxial surge protector with gas discharge tube.   Internally I air gap the modem and router with fiber/Ethernet converters and at the end of long runs I use Ethernet isolators (not surge protectors) which are tested to UL 60-601

The lightening is 2.3km away from you. 

At the first sign of a storm simply go outside and hold up a tall metal pole to attract the lightening and hopefully divert it from your house. Works every time.

@Wolf_garcia

Perhaps flying an aluminum foil kite with thing copper "string". 

try taking the penny out of the electrical socket

Not just switch off, completely unplug. I lost my Luxman amp, Bryston CD player, and Martin Logan speakers in a lightning incident. Fortunately homeowner's insurance covered most of it, and Bryston stood by their astonishing warranty, otherwise I would have been out a very significant amount of money

Had a lightening strike that came in thru my dog's "invisible fence". Took out my computer and Bryston amp. Bryston service said it wasn't covered in their warranty BUT "this time" we'll fix it.  I'm a Bryston fanboy for life . . . but I do have a whole house and a protected separate circuit for my toys now. 

Good idea to avoid showers / baths as well.

My system was hit by lightening, it traveled through the coax cable line into my video processor via HDMI and then hit my projector. I had everything on quality surge protectors but it didn't matter. The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out so having things plugged into different wall outlets is an issue. I have since purchased a PS Audio P15 Powerplant power regenerator. Not only do I have zero static on my line I power everything from one outlet (yes it is a pain to have a 50ft cord going to the projector along the ceiling in a wrap with the HDMI cord). The pool of capacitance it has is fantastic and it lowered the noise floor, the base is much more effortless, and the colors pop on the projector believe it or not. Plus there is a huge quality of life bonus, I've programmed everything to turn on and off in the correct order, what a luxury. Now the system is unplugged all the time, I check for any weather before hand with "The Weather Bug" app which tracks lightening in real time. If I sniff the ozone of a storm the system stays unplugged, as well as the computer. I'm playing chess that evening on my Chessnut, no music or movies for me!

@hifidream  - I'm curious.  What, if any, coax protection did you have at the time?  We had a significant near by strike here when I moved (2021 I think) that took out the cable provider's equipment and every single modem in my small subdivision.  I used an outdoor gas discharge protector.  While I did lose the modem, the Wifi router it was attached to and all the gear attached to it directly was not affected. 

My system was hit by lightening, it traveled through the coax cable line into my video processor via HDMI and then hit my projector. I had everything on quality surge protectors but it didn’t matter. The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out so having things plugged into different wall outlets is an issue.

The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out

@hifidream ,

I’m pretty sure he meant more than one earth connection to the electrical grounding system of the house. (From mother earth to the inside of the house and back out of the house to mother earth.)

All mother earth connections should be connected to the main electrical service equipment, service entrance neutral conductor that is bonded to the metal enclosure of the electrical service equipment. That especially includes the shield of the CATV providers coax cable. 

On the outside of your house just before where the coax cable enter your house there should be a grounding block. (sometimes the block is mounted in a plastic weather proof/resistant enclosure).

Here is where it can get tricky. How close is the grounding block from the outdoors electric meter socket enclosure? More than 20 feet?

If  20ft or less a minimum #14awg copper ground wire, (I would use #12awg solid copper minimum), install from the ground block lug to the grounding electrode conductor that come outdoors from the main electrical service equipment and connects to a ground rod(s) in the earth. (Some times the electrical service equipment is mounted outdoors beside the electric meter socket enclosure).

Use an electrical split bolt to connect the #12awg solid copper wire to the #6 bare solid copper wire,  (#6awg solid bare copper is the minimum size per code). (I prefer #4awg bare solid copper wire).

 Clean the bare #6 copper ground wire with a piece of emery cloth or fine sand paper.

Example of a split bolt. 

If distance from the grounding block to the grounding electrode conductor is greater than 20FT post back for instructions.

Grounding and Bonding of Communications Systems   

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I’m pretty sure he meant more than one earth connection to the electrical grounding system of the house. (From mother earth to the inside of the house and back out of the house to mother earth.)

Nope. 

Lightning strikes from coax or network connections aren’t necessarily from ground to ground.  They seek ground potential, but they are not necessarily carried in by the ground conductors. 

What the tech was referring to is that lightning potential seeks a path to ground, and will find the lowest insulated point to go through.  

This is a reason why I specifically do NOT recommend grounding Ethernet "surge protectors."  Best to deny a surge a path via isolators than to allow a low voltage current path which may also convert common mode to differential and enable the passing of a surge downstream. 

In the case of an outside surge coming in from other than the power lines, the series mode protectors have the edge as instead of encouraging the surge path they deny it, but only on the hot wire I believe.  

What the tech was referring to is that lightning potential seeks a path to ground, and will find the lowest insulated point to go through.  

Lightning is non discriminating. It will take any path that is provided to earth. The lower the soil to grounding electrode, (ground rod), resistance the better. Simple OHMS LAW.

Why give it two paths. In and out in the blink of an eye.

Let’s wait for @hifidream to respond to my post above. At this point we don’t know how the CATV grounding block is grounded. I can say if the CATV coax cable is on the opposite side of the house, than the electrical service is on, a ground stake was stuck in the earth and the grounding block was only connected to earth at the ground stake.  Lightning loves those type of grounding installations.  Lightning also loves audio isolated ground rods too.

Bonding communications systems

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